OPERATING AGREEMENT

                                       OF

                               IMG TECHNOLOGY, LLC


                            Dated as of March 5, 1999






                                TABLE OF CONTENTS
                                                                            Page

PRELIMINARY STATEMENT......................................................... 1

ARTICLE I                           DEFINITIONS............................... 1

         Section 1.1                Definitions............................... 1
         Section 1.2                Rules of Construction..................... 4

ARTICLE II                          ORGANIZATIONAL MATTERS.................... 5

         Section 2.1                Organization.............................. 5
         Section 2.2                Company Name.............................. 5
         Section 2.3                Principal Place of Business............... 5
         Section 2.4                Registered Agent.......................... 5
         Section 2.5                Company Purpose........................... 5
         Section 2.6                Term of Company........................... 5
         Section 2.7                Title to Property......................... 5



ARTICLE III                         CAPITALIZATION............................ 5

         Section 3.1                Initial Capital Contributions of the
                                      Members................................. 6
         Section 3.2                Admission of Members...................... 6
         Section 3.3                Company Capital........................... 6

ARTICLE IV                          MANAGEMENT OF THE COMPANY; ACTS OF
                                      MEMBERS AND MEMBER MEETINGS............. 6

         Section 4.1                Management................................ 6
         Section 4.2                Voting Rights............................. 6
         Section 4.3                Management Powers......................... 6
         Section 4.5                Meetings of the Members................... 8
         Section 4.6                Limitation of Liability................... 9
         Section 4.7                Liability for Certain Acts................ 9
         Section 4.8                Reimbursement of Expenses;
                                      Compensation............................10



ARTICLE V                           TRANSFERS; RESTRICTIONS ON TRANSFERS;
                                      ADDITIONAL MEMBERS .....................10

         Section 5.1                Transfer Procedures.......................10
         Section 5.2                Restrictions on Transfers; Permitted
                                      Transfers...............................10
         Section 5.3                Transfers by IMMUNOMEDICS.................11
         Section 5.4                Transfers by GOLDENBERG...................11
         Section 5.6                Additional Members........................12

ARTICLE VI                          DISSOLUTION AND WINDING UP................12

         Section 6.1                Dissolution Events........................12

ARTICLE VII                         REMEDIES FOR BREACH.......................13

         Section 7.1                Specific Enforcement......................13
         Section 7.2                Attorneys Fees and Expenses...............13

ARTICLE VIII                        AMENDMENTS................................13



ARTICLE IX                          MISCELLANEOUS.............................13

         Section 9.1                Notices...................................13
         Section 9.2                Consents..................................14
         Section 9.3                Binding Effect............................14
         Section 9.4                Further Actions...........................14
         Section 9.5                Headings and Captions.....................14
         Section 9.6                Relationship of this Agreement to the
                                      Default Rules...........................14
         Section 9.7                Relationship of this Agreement and
                                      the Certificate of Formation............14
         Section 9.8                Counterparts..............................14
         Section 9.9                Creditors and Other Third Parties.........14
         Section 9.10               Governing Law.............................14
         Section 9.11               No Waiver.................................15
         Section 9.12               Integration...............................15
         Section 9.13               Severability..............................15



ADDENDUM.................................................................... A-1

MEMBERSHIP ROSTER..................................................... EXHIBIT A

INITIAL CAPITAL CONTRIBUTIONS......................................... EXHIBIT B




         THIS  OPERATING  AGREEMENT is entered into and shall be effective as of
March 5,  1999,  by and  between  IMMUNOMEDICS,  INC.,  a  Delaware  corporation
("IMMUNOMEDICS"),   and   DAVID   GOLDENBERG,   an   individual   ("GOLDENBERG")
(IMMUNOMEDICS and GOLDENBERG each a "Member" and sometimes collectively referred
to herein  as the  "Members"),  and IMG  TECHNOLOGY,  LLC,  a  Delaware  limited
liability company (the "Company").


                              PRELIMINARY STATEMENT

         A.       The Company was formed on February 25, 1999 by the filing of a
                  Certificate of Formation, duly executed by Tanya M. Taylor (in
                  her capacity as organizer of the Company, the "Organizer"), in
                  the  office  of  the  Secretary  of  the State of the State of
                  Delaware.  On  February  25,  1999,  the  Organizer executed a
                  Statement of the Organizer  certifying to the formation of the
                  Company  and  the  appointment  of IMMUNOMEDICS as the initial
                  Member of the Company.

         B.       The  Company  and  Coulter Corporation intend to enter into an
                  Operating   Agreement   of   IBC  Pharmaceutical,   LLC  ("IBC
                  Pharmaceutical")  (the "IBC Operating Agreement"),  as Members
                  pursuant  to  which  the  Company  will, through IMMUNOMEDICS,
                  contribute certain targeted technology to IBC Pharmaceutical.

         C.       The  parties  to  this  Agreement  wish  to  set  forth  their
                  agreements regarding the financing,  ownership, governance and
                  operation  of  the  Company.   To  reflect the foregoing,  the
                  parties hereto agree to continue  the Company on the terms and
                  conditions set forth below.


                                    ARTICLE I

                                   DEFINITIONS

         Section 1.1  Definitions. When used in this Agreement and the Addendum,
the  following  capitalized  terms  shall  have the  meanings  set forth in this
Section, unless the context otherwise requires:

         "Accountants"  means such  regionally or nationally  recognized firm of
independent public accountants as may be engaged by the Members on behalf of the
Company.

         "Act" means the Delaware Limited  Liability Company Act as set forth in
Sections  18-101 to 18-1109 of the Delaware  Code,  as amended from time to time
(or any corresponding provision or provisions of succeeding law).



         "Addendum" means that addendum  annexed hereto and incorporated  herein
by  reference,  which  contains  rules of  governance  with  respect  to various
financial  matters  pertaining to the Company,  including  issues  pertaining to
allocations of profits and losses and with respect to applicable rules under the
Code and Treasury Regulations.

         "Affiliate"  means,  with  respect to any  person,  (i) any person that
directly  or  indirectly  through  one or more  intermediaries  controls,  or is
controlled by, or is under common control with, the specified  person;  (ii) any
person that is an officer of,  director of, partner in, or trustee of, or serves
in a similar  capacity  with  respect to, the  specified  person or of which the
specified person is an officer,  member or trustee, or with respect to which the
specified person serves in a similar capacity (iii) any person that, directly or
indirectly, is the beneficial owner of ten percent (10%) or more of any class of
equity  securities of the specified  person or of which the specified  person is
directly or indirectly the beneficial  owner of ten percent (10%) or more of any
class of equity  securities;  or (iv) any  relative  or spouse of the  specified
person  who  makes his home with that of the  specified  person;  except  that a
person who is a member in a company  or joint  venture  with the  Company or any
Affiliate  of the  Company is not an  Affiliate  of the Company or the Member if
such person is not otherwise an Affiliate thereof.

         "Agreement" means this operating agreement,  as originally executed and
as amended from time to time.

         "Bankruptcy" means, with respect to any Person, the (i) commencement by
such Person of a voluntary  case for relief as a debtor under the United  States
Bankruptcy  Code or the filing by such Person of a petition to take advantage of
any other present or future  insolvency act or other  applicable law relating to
bankruptcy,  insolvency,  reorganization,  or relief of debtors;  (ii) making by
such Person of an assignment for the benefit of creditors; (iii) consent by such
Person to, or  acquiescence in by such Person of, the appointment of a receiver,
liquidator,  trustee,  custodian, or other similar official of such Person or of
the whole or any substantial  part of such Person's  properties or assets;  (iv)
entering by a court of competent  jurisdiction of an order, judgment, or decree,
appointing a receiver, liquidator, trustee, custodian, or other similar official
of such  Person  or of the  whole  or any  substantial  part  of  such  Person's

                                       2


properties or assets, which order,  judgment,  or decree has remained unvacated,
or not set aside, or unstayed,  for a period of not less than one hundred twenty
(120) days; (v)  commencement  of an involuntary  case against such Person under
the United States  Bankruptcy  Code, or filing against such Person of a petition
seeking similar relief under any other present or future insolvency act or other
applicable law relating to bankruptcy, insolvency,  reorganization, or relief of
debtors,  which case or petition has remained  undismissed for not less than one
hundred twenty (120) days;  (vi)  assumption,  under the provisions of any other
law for the relief or aid of debtors, by any court of competent  jurisdiction of
custody or control of such Person or the whole or any  substantial  part of such
Person's  properties or assets,  which custody or control  remains  unvacated or
unstayed for not less than one hundred  twenty (120) days;  or (vii) in the case
of a Member that is a corporation, partnership or limited liability company, the
liquidation or dissolution of such Member.

         "Business  Day" means any day on which the New York Stock  Exchange  is
neither required nor authorized to close.

         "Capital Account" means the capital account established on the books of
the Company for each Member in accordance  with the provisions of Section 2.1 of
the Addendum.

         "Capital Contribution" means, with respect to any Member, the amount of
money  and the  fair  market  value  of any  property  (other  than  money  or a
promissory note that is made by such Member and that is not readily traded on an
established  securities  market)  contributed to the Company by such Member with
respect to his interest in the Company.

         "Certificate of Cancellation" means a certificate of cancellation filed
with the Secretary pursuant to the Act to cancel the Certificate of Formation.

         "Certificate  of Formation"  means the  certificate of formation  filed
with the Secretary on February 25, 1999 in connection  with the formation of the
Company, as the same may be amended from time to time.

         "Company"  means the  limited  liability  company  formed and  operated
pursuant to the Articles of Organization and this Agreement.

         "Default  Rules" means a rule provided by the Act that (i)  structures,
defines or regulates the finances,  governance,  operations or other aspect of a
limited liability formed under the Act, and (ii) applies except to the extent it
is negated or modified through the provisions of a limited  liability  company's
articles of organization or operating agreement.

         "Delaware  Code"  means  Chapter  18,  Title  6  of  the  Delaware Code
Annotated.

         "Dissolution  Event" means an event  described in Section 7.1.  "Fiscal
Year" means (i) the period  commencing on the date of this  Agreement and ending
on the  following  December  31; (ii) any  subsequent  twelve (12) month  period
beginning  on January 1 and ending on  December  31; or (iii) any portion of the
period  described  in clauses  (i) or (ii) for which the  Company is required to
close its books and allocate  Profits (as such term is defined in the Addendum),
Losses  (as such term is  defined in the  Addendum)  and other  items of income,
gain, loss, deduction or credit.

                                       3


         "Initial Capital  Contribution"  means, with respect to any Member, the
aggregate Capital  Contributions made by such member as of the effective date of
this Agreement.

         "Interest" means a Member's  membership  interest in the Company at any
given time,  including such Member's  interest in the capital and profits of the
Company.

         "Member"  means,  at any time,  any  Person who is then a member of the
Company (within the meaning of Section 102(q) of the Act).

         "Permitted  Transferee"  means,  with  respect to any  Member,  (i) his
spouse,  children  or  grandchildren,  (ii) a  trustee  of a trust  for the sole
benefit of any one or more of the persons  identified  in the  preceding  clause
(i), or (iii) any  corporation,  partnership or other entity  controlled by such
Member or any person identified in the preceding clause (i).

         "Person"   means  any   individual  or  trust,   estate,   partnership,
corporation, limited liability company or other entity.

         "Secretary"  means the Office of the Secretary of State of the State of
Delaware.

         "Transfer" means to sell,  assign,  convey,  donate,  transfer,  lease,
mortgage,  pledge, encumber or otherwise dispose of all or part of any Interest,
or to contract to do any of the foregoing.


         Section  1.2  Rules  of  Construction.  Unless  the  context  otherwise
requires,  (i) a term shall have the meaning assigned to it in Section 1.1; (ii)
an accounting term not otherwise  defined shall have the meaning  assigned to it
in accordance with generally accepted  accounting  principles;  (iii) "or" shall
not be exclusive;  (iv) words in the singular shall include the plural, and vice
versa;  (v) words in the masculine gender shall include the feminine and neuter,
and vice versa;  and (vi) any  reference to an "Article"  or  "Section,"  if not
otherwise  modified,  shall be a  reference  to an  Article  or  Section of this
Agreement.

                                       4


                                   ARTICLE II

                             ORGANIZATIONAL MATTERS

         Section 2.1  Organization.   On  February  25,  1999,  a Certificate of
Formation  in  compliance  with  Section 18-201(a) of the Act was filed with the
Secretary causing the organization of the Company, effective as of said date.

         Section 2.2  Company Name.  The name of the Company is "IMG TECHNOLOGY,
LLC".

         Section 2.3  Principal Place of Business.  The principal place of
business of the Company is located at 300  American  Road,  Morris  Plains,  New
Jersey  07950.  The  Members may change the  principal  place of business of the
Company  to any other  place  within or  without  the State of New  Jersey.  The
Company  may  maintain  such  additional  offices and places of business in such
locations as the Members may deem necessary or advisable.

         Section 2.4  Registered Agent.   The  Secretary  is  designated  as the
Company's  registered  agent upon whom process against the Company may be served
within the State of Delaware. The President is authorized to appoint a successor
registered  agent or agents if the  registered  agent or agents resign or if the
Members otherwise deem it desirable to do so.

         Section 2.5  Company Purpose.   The  purposes of the Company are (i) to
engage in any lawful act or activity for which limited  liability  companies may
be formed under the Act, and (ii) to engage in any and all activities  necessary
or incidental thereto.

         Section 2.6  Term of Company.  The term of the Company commenced on the
date the Articles were filed with the Secretary and shall  continue until twelve
o'clock noon on December  31, 2050,  unless  terminated  sooner  pursuant to the
provisions of Article XII.

         Section 2.7  Title to Property.  All  property  owned  by  the  Company
shall be  owned  by the  Company  as an  entity  and no  Member  shall  have any
ownership  interest in such property in his  individual  name, and each Member's
Interest  shall be personal  property for all  purposes.  At all times after the
date of this  Agreement,  the Company shall hold title to all of its property in
its own name and not in the name of any Member.

 
                                   ARTICLE III

                                 CAPITALIZATION

         Section 3.1  Initial Capital Contributions of the Members.  The Capital
Contribution of each of the Members,  as of the date hereof,  is as set forth on
the schedule annexed hereto as Exhibit B.

                                      5



         Section 3.2  Admission of Members.  The  Company  shall  not  accept  a
Capital  Contribution  on behalf of the  Company  from any person  that is not a
Member and shall not admit any such person to the Company as a Member.

         Section 3.3  Company Capital.

                  Section 3.3.1.  Interest.  The  Company  shall not be required
to pay interest on any Capital Contribution.

                  Section 3.3.2.  Returns and Withdrawals.  No Member shall have
the right to withdraw or receive any return of his Capital Contribution,  except
as expressly  provided by Section  3.3.1 and Articles IV and VI of the Addendum,
and no Capital  Contribution may be returned in the form of property (other than
money), except as specifically provided by Section 6.8 of the Addendum.



                                   ARTICLE IV

                           MANAGEMENT OF THE COMPANY;
                       ACTS OF MEMBERS AND MEMBER MEETINGS


         Section 4.1  Management.  The  overall  management of the Company shall
be vested in its  Members  and all  management  decisions  with  respect  to the
Company shall be made in accordance with Section 4.3 and 4.4.

         Section 4.2  Voting Rights.  On  matters  subject  to  a  vote  of  the
Members,  the Members shall vote in proportion with their percentage Interest in
the Company.

         Section 4.3 Management Powers. Management and control of the affairs of
the Company shall be vested in the Members. The rights and powers of the Members
shall be  exercised by them in the manner set forth  herein.  In addition to the
powers now or  hereafter  granted by law and as  otherwise  provided for in this
Agreement,  the Members for, and in the name and on behalf of the Company, shall
have the power,  either directly or through one or more  intermediaries,  to (i)
acquire by purchase,  lease or otherwise any real or personal property which may
be necessary,  convenient or incidental to the accomplishment of the purposes of
the Company;  (ii) operate,  maintain,  finance,  improve construct,  own, grant

                                       6


options  with  respect to,  sell,  convey,  assign or lease any real or personal
property which may be necessary,  convenient or incidental to the accomplishment
of the purposes of the Company;  (iii) incur  indebtedness or issue evidences of
indebtedness which may be necessary,  convenient,  or incidental to the purposes
of the Company  and secure the same by  mortgage,  pledge,  or other lien on any
assets  of  the  Company;  (iv)  execute  any  and  all  agreements,  contracts,
documents,  certifications,  and instruments which may be necessary, convenient,
or incidental in connection with the acquisition, financing, operation, and sale
of any assets of the Company; (v) prepay in whole or in part, refinance, recast,
increase,  modify,  or extend any borrowings or indebtedness of the Company and,
in   connection   therewith,   to  execute   any   extensions,   consolidations,
modifications,  or renewals of any mortgages on any assets of the Company;  (vi)
perform,  or cause to be performed,  all of the Company's  obligations under any
agreement  to  which  the  Company  is a  party  or is  otherwise  bound;  (vii)
prosecute,  defend, or compromise upon such terms as they may determine and upon
such evidence as they may deem  sufficient,  any  obligation,  suit,  liability,
cause of action, claim, either in favor of or against the Company; (viii) employ
employees, agents, attorneys, auditors, accountants, and depositories and to pay
fees,  expenses,  and other  compensation  to such persons;  (ix)  establish and
maintain  reserves  for such  purposes  and in such  amounts as the Members deem
appropriate  from time to time; (x) make appropriate  elections  permitted under
applicable tax law,  provided,  however,  that such  elections  shall not in the
opinion of counsel to the Company or of the Accountants be  disadvantageous to a
majority-in-interest of the Members; and (xi) engage in any kind of activity and
perform and carry out contracts of any kind necessary to, in connection with, or
incidental  to, the  accomplishment  of the purposes of the  Company,  as may be
lawfully carried on or performed by a limited  liability  company under the laws
of the State of Delaware  and in each state where the Company has  qualified  or
does business.

         Section 4.4  Exclusive  Duty  to the Company.  Each Member shall devote
his or its full business time and attention to the business of the Company.

                                       7


         Section 4.5 Meetings of the Members.

                  Section  4.5.1  Procedures.  Meetings  of the  Members  may be
called by Members possessing,  in the aggregate, at least a twenty (20%) percent
Interest in the Company.  The notice shall state the place, date and time of the
meeting, and may, but shall not be required to, state the purpose of the meeting
and the business to be transacted.  Notice of any such meeting shall be given to
all  Members  not less than ten (10)  Business  Days nor more than  thirty  (30)
Business  Days prior to the date of such  meeting.  No notice of any  meeting of
Members need be given to any Member who attends in person or is  represented  by
duly executed  proxy, or to any Member entitled to such notice who, in a writing
executed and filed with the records of the meeting,  either  before or after the
time thereof, waives such notification.  Members may vote in person, by proxy or
by telephone at such meeting and may waive advance  notice of such meeting.  The
presence in person or by proxy of a majority  in  interest of the Members  shall
constitute  a quorum for all  meetings of the  Members.  Each meeting of Members
shall be held at the  Company's  principal  place of  business  or at any  other
location set forth in the notice  thereof.  At such meetings,  the Members shall
transact such business as may properly be brought before the meeting, whether or
not notice of such meeting referenced the action taken at such meeting.

                  Section 4.5.2  Manner of Acting.  If a quorum is present, the
affirmative  vote of those Members holding a majority in interest present at the
meeting shall be the act of the Members.

                  Section 4.5.3  Record  Date.  For  the  purpose of determining
the Members  entitled to notice of, or to vote at, any meeting of the Members or
any adjournment  thereof,  the Member calling the meeting may fix, in advance of
sending of the  notice,  a date as the record  date for any such  determination.
Such date  shall not be more than  thirty  (30) days nor less than ten (10) days
before any such meeting.

                  Section 4.5.4  Proxies.  Each  Member may authorize any Person
or Persons to act for it by proxy on all  matters in which a Member is  entitled
to  participate,   including  waiving  notice  of  any  meeting,  or  voting  or
participating  at a meeting.  Every proxy must be signed on behalf of the Member
or by its  attorney-in-fact.  No proxy  shall be valid after the  expiration  of
eleven (11) months from the date thereof unless otherwise provided in the proxy.
Every proxy shall be revocable at the direction of the Member executing it.


                  Section 4.5.5  Management  of  Meetings.   A representative of
IMMUNOMEDICS shall preside at and conduct any meeting of the Members.


                                        8


                  Section 4.5.6  Meetings by Conference Telephone.   Any  action
required to be taken at a meeting of the Members may be taken at a meeting  held
by means of conference telephone or other  communications  equipment by means of
which  all   Persons   participating   in  the  meeting  can  hear  each  other.
Participation  in such a meeting  shall  constitute  presence  in person at such
meeting.

                  Section 4.5.7  Actions Without a Meeting.  Any action required
or  permitted  to be taken at a meeting of the  Members  may be taken  without a
meeting by written action signed by Members who possess the percentage Interests
equal to the percentage Interests that would be required to take the same action
at a meeting of the  Members at which all  Members  were  present.  The  written
action is effective when signed by Members  possessing  the required  percentage
Interests, unless a different effective time is provided in the written action.

         Section 4.6  Limitation of Liability.   Except as otherwise required by
applicable law, no Member shall be personally liable for the debts,  obligations
or liabilities of the Company,  whether arising in tort,  contract or otherwise,
solely by reason of being a Member. A Member shall be liable only to make his or
its initial Capital Contribution, and shall not be required to lend any funds to
the Company or, after his or its initial  capital  contribution  shall have been
made, to make any further Capital  Contributions  to the Company or to repay any
Member,  or any creditor of the Company all or any part of the negative  balance
of his  Capital  Account,  provided  that a  Member  may be  required  to  repay
distributions made to it as provided in Section 18-607 of the Act.

         Section 4.7  Liability for Certain  Acts.  The Members  shall  exercise
their business judgment in managing the business, operations, and affairs of the
Company. Unless fraud, willful misconduct or gross negligence shall be proved by
a nonappealable court order,  judgment,  decree or decision,  no Member shall be
liable or otherwise  accountable in damages to the Company or any Member for any
mistake of fact or judgment or for the doing of any act or the failure to do any
act in conducting the business, operations and affairs of the Company, which may
cause or result in any loss or damage to the Company or to any Member. No Member
shall be deemed to have in any way guaranteed the return of the Members' Capital
Contributions  or a profit for the Members from the  operations  of the Company,
and no Member  shall be  responsible  to any  Member  because  of a loss of such
Member's  investment,  unless  such loss  shall  have been the  result of fraud,
willful misconduct or gross negligence of such Member.

                                        9



         Section 4.8  Reimbursement of Expenses; Compensation.

                  Section 4.8.1  The Company shall reimburse each Member for the
out of pocket expenditures he may incur in managing the business of the Company,
including,  without  limitation,  travel and lodging expenses upon submission of
appropriate documentation expenses.

                  Section 4.8.2  No Member shall receive any interest, salary or
drawing  with  respect to his Capital  Contributions  or Capital  Account or for
services rendered on behalf of the Company,  or otherwise,  in his capacity as a
Member, except as otherwise provided in this Agreement.



                                    ARTICLE V

                      TRANSFERS; RESTRICTIONS ON TRANSFERS;
                               ADDITIONAL MEMBERS

         Section 5.1 Transfer Procedures. Except as otherwise expressly provided
in this  Agreement  and subject in all respects to the other  provisions of this
Article V, the transfer of any Interest  upon the books of the Company  shall be
accomplished  only  by the  submission  to the  Company  by  the  transferor  or
transferee of a duly executed and  acknowledged  counterpart  of the  instrument
making  such  transfer  together  with  such  other  instrument  or  instruments
signifying  the  transferee's  agreement to be bound by all of the provisions of
this Agreement (including but not limited to all of the transferor's obligations
hereunder),  all of the  foregoing  in such  form  and  substance  as  shall  be
reasonably  satisfactory  to  the  Company.  If  such  instruments  are  not  so
submitted,  the Company need not recognize any such transfer as being  effective
for any purpose.

         Section 5.2  Restrictions on Transfers; Permitted Transfers.

                  Section 5.2.1  General Restrictions on  Transfer.   Except  as
otherwise  permitted by this  Agreement,  no Member shall Transfer any or all of
his or its Interest without the consent of all of the other Members.

                  Section 5.2.2  Permitted  Transfers.   Subject  to  compliance
with the provisions of this Agreement,  any Member may voluntarily  Transfer all
or any part of his or its Interest to any  Permitted  Transferee.  Such Transfer
shall not be effective  unless the  transferring  Member  provides notice to the
Company  setting  forth  (i)  the  identity  of the  transferee,  and  (ii)  the
consideration,  if any, paid for the Transferred Interest at least ten (10) days
before the effective date of the Transfer.

                                       10


         Section 5.3  Transfers by IMMUNOMEDICS.   IMMUNOMEDICS  may at any time
Transfer  all or any  portion  of its  Interest  pursuant  to  Section  5.1  for
consideration  to  an  unaffiliated  third  party,   subject  to  the  following
provisions:

                  (i)      Mandatory  Sale by GOLDENBERG.   In  the  event  that
IMMUNOMEDICS  intends to transfer its entire Interest to an  unaffiliated  third
party  pursuant to the  provisions  of this Section 5.3, then upon the demand of
IMMUNOMEDICS, GOLDENBERG shall be required to sell to the proposed purchaser all
of his Interest,  such sale to be made on the same terms,  conditions  and price
and at the same time as the proposed purchase from IMMUNOMEDICS.

                  (ii)  Optional  Sale  by   GOLDENBERG.   Notwithstanding   the
provisions  set forth in  paragraph  (i) of this  Section 5.3, in the event that
IMMUNOMEDICS  receives  and intends to transfer a portion of its  Interest to an
unaffiliated third party pursuant to the provisions of this Section 5.3 and such
portion of its Interest is equal to or greater than  fifty-one  (51%) percent of
the total  Interest of all  Members,  then as a condition to the closing of such
sale,  the  proposed  purchaser  shall be  required  to offer to  purchase  from
GOLDENBERG  that same  percentage of his Interest as the percentage  obtained by
multiplying  IMMUNOMEDICS'  percentage  Interest  being  sold  times the  entire
Interest then held by IMMUNOMEDICS.

         Section 5.4 Transfers by GOLDENBERG.

                  Section  5.4.1  Purchase  Option.  If at any  time  GOLDENBERG
desires to Transfer all or any portion of his Interest other than to a Permitted
Transferee pursuant to Section 5.1 for consideration, he must in any event first
provide  IMMUNOMEDICS  an opportunity to purchase his Interest,  or such portion
thereof,  by notice,  for  consideration  and upon other terms and conditions as
GOLDENBERG  shall determine.  IMMUNOMEDICS  shall have sixty (60) days after the
mailing  date of such notice in which to accept the offered  Interest by written
notice to GOLDENBERG.

                  Section  5.4.2 Failure to Exercise  Option.  In the event that
IMMUNOMEDICS  does not elect to  purchase  all or such  portion of the  Interest
offered by GOLDENBERG pursuant to Section 5.4.1,  GOLDENBERG shall be free for a
period of one (1) year after the  expiration  of the sixty  (60) day  acceptance
period,  to transfer all, but not less than all, of his offered  Interest to any
prospective  transferee for consideration and on such other terms and conditions
no more favorable to such transferee than those offered to IMMUNOMEDICS.  If the
consideration  or other terms or conditions  offered to such transferee are more
favorable  than those  offered to  IMMUNOMEDICS,  GOLDENBERG  must  re-offer the
offered Interest to IMMUNOMEDICS pursuant to the provisions of Section 5.4.1. In
the event that a Transfer of the offered  Interest is effected  pursuant to this
Section 5.4.2,  GOLDENBERG  shall,  within ten (10) days thereafter,  certify to
IMMUNOMEDICS  the identity of the transferee and that the  consideration of such
Transfer was no more favorable than that offered to IMMUNOMEDICS.

         Section 5.5  Repayment of Loans.   Whenever  the entire Interest of any
Member is purchased pursuant to the provisions of this Agreement, the purchasing
Member  or third  party may set off  against  the  first  payment  to be made on
account of the purchase  price of the Interest  purchased  hereunder  the unpaid
balance of any indebtedness owing by such Member to the Company.

                                       11


         Section 5.6  Additional Members.  Additional Members may be admitted to
the Company upon (i) the unanimous written consent of all of the Members,  which
consent  may be  granted or  withheld  in their  sole  discretion,  and (ii) the
agreement  of the new  Member  in  writing  to be  bound  by the  terms  of this
Agreement.


                                   ARTICLE VI


                           DISSOLUTION AND WINDING UP


         Section 6.1  Dissolution Events.

The Company shall dissolve and shall commence  winding up and  liquidating  upon
the first to occur of any of the following events:

(i)   12:00 p.m. on December 31, 2050;

(ii)  upon  written  notice  from  the  Members  of their desire to commence the
voluntary  dissolution  of the Company,  in accordance with the terms of Section
5.3.3; or

(iii) the entry of a decree of judicial  dissolution under Section 18-802 of the
Act.

         The death, retirement, resignation, expulsion or Bankruptcy of a Member
or the occurrence of any other event which  terminates the continued  membership
of a Member in the Company shall not result in the dissolution or liquidation of
the Company and the business of the Company shall continue  notwithstanding  the
occurrence of such event. The foregoing  sentence shall be deemed to be a stated
right to continue by the Company in  conformity  with  Section  18-801(b) of the
Act.  Notwithstanding  any  provision of the Act, the Company shall not dissolve
prior to the occurrence of a Dissolution Event.

                                       12



                                   ARTICLE VII

                               REMEDIES FOR BREACH

         Section 7.1  Specific Enforcement.   All breaches of this Agreement are
subject to specific enforcement,  without prejudice to the right to seek damages
or other remedies.

         Section 7.2  Attorneys Fees and Expenses.  If the Company resorts to
litigation to remedy a breach of this Agreement by a Member or former Member and
the Company  prevails  in the  litigation,  in  addition  to any other  remedies
available to the Company under this Agreement or by law, the Company may collect
its reasonable attorneys fees and expenses of litigation from such Member.


                                  ARTICLE VIII

                                   AMENDMENTS

         Members possessing at least a majority-in-interest  of the Company may,
without prior notice to or consent of any other  Member,  amend any provision of
this  Agreement;  provided,  however,  that no amendment  that has the effect of
increasing  the  liability  of any Member or  adversely  affecting  any Member's
interest in the income,  gain or loss of the Company or in cash distributions by
the  Company  may become  effective  unless  affirmatively  consented  to by all
Members who would be adversely affected thereby. Written notice of any amendment
to this  Agreement  effected  pursuant to this Article VIII shall be sent to all
Members within a reasonable period of time after its adoption.




                                   ARTICLE IX

                                  MISCELLANEOUS

         Section 9.1 Notices.  All notices  permitted or required to be given by
this Agreement shall be in writing and shall be deemed to be duly given if given
personally  with receipt  acknowledged or sent, by registered or certified mail,
return  receipt  requested,  or by fax,  or by  overnight  courier  for next day
delivery, addressed to the Company at its principal office, and addressed to the
respective  Members at their addresses set forth on the schedule  annexed hereto
as  Exhibit A,  unless  notice in writing is given of a change of address in the
manner set forth herein,  in which case notices shall be sent to the new address
so  designated.  Notice of change of address shall be deemed given when actually
received or upon refusal to accept delivery thereof;  all other notices shall be
deemed given and received on the earlier of (i) the date when actually  received
or upon refusal to accept delivery thereof,  or (ii) on the date when personally
delivered,  one (1) day after being sent by telex, fax or overnight  courier and
three (3) days after mailing, as aforesaid.

                                       13


         Section 9.2  Consents.  Any  consent  required under the Agreement must
be in writing.

         Section 9.3  Binding Effect.  Subject  to  the restrictions on transfer
set forth herein, this Agreement shall be binding upon, and inure to the benefit
of, the parties hereto and their successors and assignors.

         Section 9.4  Further Actions.  Each  of  the  Members  shall  hereafter
execute  and deliver  such  further  instruments,  including  written  powers of
attorney,  and  perform  such  further  acts as may be required to carry out the
intent and purposes of the Agreement.

         Section 9.5  Headings   and   Captions.   All   headings  and  captions
contained in the Agreement and the table of contents hereto are inserted only as
a matter of convenience  and in no way define,  limit,  extend,  or describe the
scope of this Agreement or the intent of any provision hereof.

         Section 9.6  Relationship  of  this  Agreement  to  the  Default Rules.
Regardless of whether this Agreement  specifically  refers to particular Default
Rules,  (i) if any provision of this  Agreement  conflicts  with a Default Rule,
such  provision  shall control and the Default rule shall be modified or negated
accordingly;  and (ii) if it is necessary to construe a Default Rule as modified
or negated in order to  effectuate  any provision of this  Agreement,  such Rule
shall be modified or negated accordingly.

         Section 9.7  Relationship  of  this  Agreement  and  the Certificate of
Formation.  If a provision  of this  Agreement  differs  from a provision of the
Certificate of Formation,  then to the extent allowed by law this Agreement will
govern.

         Section 9.8  Counterparts.  This  Agreement  may  be executed in one or
more  counterparts  and all such  counterparts  shall  constitute  one Agreement
binding  on all  the  parties  notwithstanding  that  all  the  parties  are not
signatories to the original or the same counterpart.

         Section 9.9  Creditors and Other Third Parties.  None of the provisions
of this Agreement are made for the benefit of, or shall be  enforceable  by, any
creditor of the Company or any other Person who is not a Member.

         Section 9.10  Governing Law.  This Agreement shall, except as otherwise
expressly provided herein, be governed by, and construed in accordance with, the
laws of the State of Delaware  without regard to the conflict of laws provisions
thereof.

                                       14


         Section 9.11  No Waiver. The failure of any party to insist upon strict
performance  of any  provision  hereof,  irrespective  of the length of time for
which such failure  continues,  shall not be a waiver of such  party's  right to
demand  strict  compliance in the future,  and no consent or waiver,  express or
implied, to any breach or default in the performance of any obligation hereunder
shall  constitute  a consent  or waiver to any other  breach or  default  in the
performance of the same or any other obligation hereunder.

         Section 9.12  Integration.    This  Agreement  constitutes  the  entire
agreement  among the parties with respect to the Company,  superseding  all oral
and written, prior or contemporaneous agreements, discussions,  negotiations, or
understandings.

         Section 9.13  Severability.  If any provision of this Agreement, or the
application  to any party or  circumstance,  shall be  determined  by a court of
competent  jurisdiction  to be  invalid  or  unenforceable  to any  extent,  the
remainder of this Agreement, or the application of such provision to such Person
or circumstance,  other than those as to which it is so determined to be invalid
or unenforceable, shall not be affected thereby, and each provision hereof shall
be valid and shall be enforced to the fullest extent permitted by law.

                                       15



         IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as
of the day and year first above written.

                                                   IMMUNOMEDICS, INC.



                                                    By: ________________________
                                                        Name: Robert J. DeLuccia
                                                  Title: Chief Executive Officer


                                                    IMG TECHNOLOGY, LLC
                                                    BY: IMMUNOMEDICS, INC.,
                                                    its sole Member


                                                    By: ________________________
                                                        Name: Robert J. DeLuccia
                                                  Title: Chief Executive Officer


                                                     ___________________________
                                                     DAVID M. GOLDENBERG





                                    ADDENDUM
\
                                    ARTICLE I

                                   DEFINITIONS


         Section 1.1  Definitions.   When  used in this Addendum to that certain
Operating  Agreement of IMG TECHNOLOGY,  LLC, dated as of February 25, 1999 (the
"Agreement"),  and in the Agreement itself,  capitalized terms used herein shall
have the meanings set forth below in this Section,  unless the context otherwise
requires.  Capitalized  terms used herein but not otherwise defined herein shall
have the meaning set forth in the Agreement.

         "Adjusted Capital Account Deficit" means, with respect to any Member at
the close of any Fiscal  Year,  the  deficit  balance in such  Member's  Capital
Account at such time  (determined  by (i) crediting to such Capital  Account (x)
the amount of such Member's Deficit Restoration  Obligation at that time and (y)
the  amount  such  Member  is  deemed  to be  obligated  to  restore  under  the
penultimate  sentences  of  Sections  1.704-2(g)(1)  and  1.704-2(i)(5)  of  the
Treasury  Regulations  at such time  (determined  after  taking into account any
changes in the  Company  Minimum  Gain and Member  Minimum  Gain of the  Company
during such Fiscal  Year);  and (ii)  charging to such  Capital  Account (x) any
adjustments  described  in  Section   1.704-1(b)(2)(ii)(d)(4)  of  the  Treasury
Regulations  that,  at such time,  are  reasonably  expected  to be made to such
Member's   Capital   Account,   (y)  any   allocations   described   in  Section
1.704-1(b)(2)(ii)(d)(5)  of the Treasury  Regulations  that,  at such time,  are
reasonably  expected  to be  made  to such  Member,  and  (z) any  distributions
described in Section  1.704-1(b)(2)(ii)(d)(6)  of the Treasury Regulations that,
at such time, are reasonably expected to be made to such Member).

         "Capital Account" means the capital account established on the books of
the Company for each Member in accordance with the provisions of Section 2.1.

         "Code" means the Internal Revenue Code of 1986, as amended from time to
time (or any  corresponding  provision or provisions of any  subsequent  federal
revenue law).

         "Company  Minimum  Gain" means,  at the close of any Fiscal  Year,  the
minimum gain of the Company (determined in accordance with Section 1.704-2(i)(2)
of the Treasury Regulations).

         "Deficit  Restoration  Obligation" means, with respect to any Member at
the end of any Fiscal Year, the amount such Member is obligated to restore under
applicable  law or pursuant to any  provision of this  Agreement on account of a

                                       A-1

deficit  balance in such  Member's  Capital  Account or is deemed  obligated  to
restore  under  Sections   1.704-2(g)(1)   and  1.704-2(i)(5)  of  the  Treasury
Regulations  (determined  after  taking into  account any changes in the Minimum
Gain and the Member Minimum Gain during such Fiscal Year).

         "Liquidator"  means the Person  appointed  by the  Members  pursuant to
Section 6.7 to oversee the liquidation of the Company.

         "Loss"  means,  for any Fiscal Year,  an amount equal to the  Company's
loss for such year, determined in accordance with Section 5.1.

         "Member  Minimum  Gain"  means an amount,  with  respect to each Member
Nonrecourse  Debt,  equal to the Company  Minimum Gain that would result if such
Member Nonrecourse Debt were treated as a Nonrecourse  Liability  (determined in
accordance with Section 1.704-2(i)(3) of the Treasury Regulations.

         "Member  Nonrecourse Debt" means any liability of the Company that is a
partner  nonrecourse  debt (as that term is defined by Section  1.704-2(b)(4) of
the Treasury Regulations).

         "Member Nonrecourse Deductions" means, for any Fiscal Year, the partner
nonrecourse  deductions of the Company for such Year  (determined  in accordance
with Section 1.704-2(i)(2) of the Treasury Regulations).

         "Net Cash Flow" means,  for any Fiscal Year,  the sum of (x) the excess
of (A) the gross cash  proceeds  received  by the  Company in such  Fiscal  Year
(including  the net cash  proceeds  from all sales and other  dispositions,  but
excluding cash proceeds  received from all borrowings or refinancing of assets),
over  (B) the  portion  of such  proceeds  used  in such  Fiscal  Year to pay or
establish  reserves  for  expenses,   capital  improvements,   debt  repayments,
replacements  and  contingencies,  and (y) any reductions in such Fiscal Year of
previously established reserves.

         "Nonrecourse  Deductions"  means,  for any Fiscal Year, the nonrecourse
deductions of the Company for such Year  (determined in accordance  with Section
1.704-2(b)(1) of the Treasury Regulations).

         "Nonrecourse  Liability"  means a liability  of the  Company  that is a
nonrecourse  liability (as that term is defined in Section  1.704-2(b)(3) of the
Treasury Regulations).

         "Profit" means,  for any Fiscal Year, the amount equal to the Company's
profit for such year, determined in accordance with Section 3.2.

                                       A-2


         "Regulatory  Allocations"   means,  collectively,  the  allocations set
forth in Section 3.5.

         "Service" means the Internal Revenue Service.

         "Treasury   Regulations"   means  the  official   Treasury   Department
interpretation of the Code found in Title 26 of the Code of Federal Regulations.

         Section  1.2  Rules  of  Construction.  Unless  the  context  otherwise
requires,  (i) a term shall have the meaning assigned to it in Section 1.1; (ii)
an accounting term not otherwise  defined shall have the meaning  assigned to it
in accordance with generally accepted  accounting  principles;  (iii) "or" shall
not be exclusive;  (iv) words in the singular shall include the plural, and vice
versa;  (v) words in the masculine gender shall include the feminine and neuter,
and vice versa;  and (vi) any  reference to an "Article"  or  "Section,"  if not
otherwise  modified,  shall be a  reference  to an  Article  or  Section of this
Addendum.


                                   ARTICLE II

                       CAPITAL STRUCTURE; CAPITAL ACCOUNTS

         Section 2.1  Establishment.    A   single   Capital  Account  shall  be
established  on the  books of the  Company  for  each  Member.  Initial  Capital
Accounts shall be as set forth on Exhibit B.

         Section 2.2  Maintenance  of  Capital  Accounts.   The  Capital Account
established  for any Member shall be maintained in accordance with the following
rules.

                  Section 2.2.1 Basic Rules. The Capital Account established for
any Member shall be (i) credited with (A) such Member's  Capital  Contributions,
(B) such  Member's  allocable  share of  Profits  and any items in the nature of
income or gain that are specially allocated pursuant to Section 3.3, and (C) the
amount of any Company liabilities assumed by such Member or which are secured by
any property  distributed  to such Member by the Company;  and (ii) charged with
(A) the  amount  of money  and the  gross  fair  market  value  of any  property
distributed to such Member pursuant to any provision of this Agreement, (B) such
Member's  allocable  share of Losses  and any items in the  nature of expense or
loss that are specially  allocated pursuant to Section 3.3 of the Addendum,  and
(C) the amount of such Member's  liabilities  assumed by the Company or that are
secured by any property contributed to the Company by such Member.

                                       A-3


                  Section 2.2.2 Treatment  of  Liabilities.   The  amount of any
liability  shall be  determined  for  purposes  of this  Section 2.2 taking into
account  Section 752(c) of the Code and any other  applicable  provisions of the
Code and the Treasury Regulations.

                  Section 2.2.3  Treatment of Certain Promissory Notes.  If a
promissory  note (other than a note that is readily  tradeable on an established
securities  market) is contributed to the Company by the person who is the maker
of such note, such person's  Capital Account shall be credited on account of the
contribution of such note only when there is a taxable  disposition of such note
by the Company or when the maker makes principal payments on such note.

         Section 2.3  Revaluations  of Property.  The book values of all Company
assets shall be adjusted to their  respective gross fair market values as of the
following times: (i) the acquisition of an additional interest in the Company by
any new or  existing  Member in  exchange  for more than a de minimis  amount of
money or other  property;  (ii) the  distribution  by the Company to a Member of
more than a de minimis amount of money or other property as consideration for an
interest in the Company;  and (iii) the  liquidation  of the Company  within the
meaning of Section  1.704-1(b)(2)(ii)(g) of the Treasury Regulations,  provided,
however,  that  adjustments  made at the times described in clauses (i) and (ii)
hereof  shall  be made  only  if the  Members  reasonably  determine  that  such
adjustments  are  necessary  or  appropriate  to reflect the  relative  economic
interests  of the Members.  The Members  shall  determine  the gross fair market
values of all Company assets pursuant to this Section 2.3.

         Section 2.4 Certain Other  Adjustments to Book Values of Property.  The
gross fair market  value of all Company  assets shall be adjusted to reflect any
adjustments  to the tax  bases of such  assets  pursuant  to  Section  743(b) or
Section  734(b) of the Code,  but only to the extent that such  adjustments  are
taken  into  account  in  determining   Capital  Accounts  pursuant  to  Section
1.704-1(b)(2)(iv)(m) of the Treasury Regulations and Section 3.1(vii) or Section
3.5.5;  provided,  however,  that such  gross  fair  market  value  shall not be
adjusted  pursuant to this Section 2.4 to the extent an  adjustment  pursuant to
Section 2.3 is required in connection  with a transaction  that would  otherwise
result in an adjustment pursuant to this Section 2.4.

         Section  2.5  Compliance  with  Applicable  Treasury  Regulations.  The
provisions of this Article II are intended to comply with Section  1.704-1(b) of
the  Treasury  Regulations  and shall be  interpreted  and  applied  in a manner
consistent with such provision. In the event that the Members holding a majority
of  the  percentage  Interest  in  the  Company,  after  consultation  with  the
Accountants,  determine that it is prudent to modify the manner in which Capital

                                       A-4


Accounts, or any credits or charges thereto are computed in order to comply with
such Section, they may make such modification, provided it is not likely to have
a material effect on the amounts distributable to any Member pursuant to Section
6.1 upon  liquidation of the Company.  The Company shall (i) after  consultation
with  the  Accountants,   make  any  adjustments  that  it  deems  necessary  or
appropriate to maintain equality between the Capital Accounts of the Members and
the amount of Company  capital  reflected on the  Company's  balance  sheet,  as
computed for book purposes, in accordance with Section  1.704-1(b)(2)(iv)(q)  of
the Treasury Regulations;  and (ii) make any other appropriate  modifications in
the event  unanticipated  events might  otherwise  cause this  Agreement  not to
comply with Section 1.704-1(b) of the Treasury Regulations.

         Section  2.6  Transfers  of  Interests.  If in any Fiscal Year a Member
transfers any or all of its Interest, then such Member's Capital Account (or the
portion thereof  attributable  to the transferred  Interest) shall carry over to
the transferee. If such transfer causes a termination of the Company for federal
income tax purposes,  the  constructive  reformation of the Company  shall,  for
purposes  of this  Article  II, be treated  as the  formation  of a new  limited
liability  company and the Capital  Accounts of the Members  shall be determined
and maintained accordingly.


                                   ARTICLE III

                           COMPUTATION AND ALLOCATION
                                       OF
                             FINANCIAL AND TAX ITEMS

         Section 3.1  Computation of Profit and Loss.  The Profit (or Loss) of
the  Company  for any  Fiscal  Year  shall be an amount  equal to the  Company's
taxable  income (or loss) for such  Fiscal Year  (computed  in  accordance  with
Section 703(a) of the Code), with the following adjustments:

                  (i) any income of the  Company  for such  Fiscal  Year that is
exempt from federal income tax and not otherwise taken into account in computing
Profit (or Loss) under this  Section 3.1 shall be added to such  taxable  income
(or loss);

                  (ii) any expenditure  described in Section 705(a)(2)(B) of the
Code for such Fiscal Year not otherwise  taken into account in computing  Profit
(or Loss) under this Section 3.1 shall be  subtracted  from such taxable  income
(or loss);

                                       A-5


                  (iii) in the  event the book  value of any  asset is  adjusted
pursuant  to  Section  2.3,  the amount of such  adjustment  shall be taken into
account  as gain or loss from the  disposition  of such  asset for  purposes  of
computing the Profit (or Loss);

                  (iv)  any  gain  or loss resulting from the disposition during
such  Fiscal Year of any asset (in a taxable  transaction)  shall be computed by
reference to the book value of such asset;

                  (v)  in  lieu  of  the  depreciation  (or  cost  recovery)  or
amortization  with  respect to any asset taken into  account in  computing  such
taxable  income (or loss),  there shall be taken into account  depreciation  (or
cost recovery) or amortization  in respect of such asset  determined by applying
the method used by the Company for federal  income tax purposes  with respect to
such asset to the book value of such asset (or if the tax basis of such asset is
zero at the  beginning of such Fiscal Year,  by applying any  reasonable  method
selected by the Members);

                  (vi)  any items in the nature of income, gain, expense or loss
that are specially allocated pursuant to  Sections 3.4 or 3.5 shall not be taken
 into account; and

                  (vii) to the  extent  an  adjustment  to the tax  basis of any
Partnership  asset  pursuant to Section  734(b) or Section 743(b) of the Code is
required pursuant to Section 1.704-1(b)(2)(iv)(m)(4) of the Treasury Regulations
to be taken  into  account  in  determining  Capital  Accounts  as a result of a
distribution  other than in complete  liquidation  of a Member's  interest,  the
amount of such adjustment shall be treated as an item of gain (if the adjustment
increases the basis of the asset) or loss (if the adjustment decreases the basis
of the asset) from the  disposition of the asset and shall be taken into account
in computing Profit (or Loss).

The amount of the items in the nature of income, gain, expense or loss available
to be  specially  allocated  pursuant  to Section  3.4 and  Section 3.5 shall be
determined by applying rules analogous to those set forth in this Section 3.1.

         Section 3.2  Allocation of Profit.

                  Section 3.2.1  Operating Profit.   Profits for any Fiscal Year
(determined  without  taking into account any item of gain  attributable  to the
sale or  exchange of any asset by the  Company or by IBC  Pharmaceutical  [other

                                       A-6


than a sale or  exchange  made in the  ordinary  course of  business])  shall be
allocated to the Members as follows:

                  (i)  first, to the Members in proportion to and to the extent
of the excess,  if any, of (x) the  aggregate  amount of Loss  allocated to each
such Member for all prior Fiscal Years pursuant to Section  3.3.2,  over (y) the
aggregate  amount of Operating  Profit allocated to such Member pursuant to this
Section  3.2.1(i) for all prior Fiscal  Years and the  aggregate  amount of gain
allocated  to such Member  pursuant  to Section  3.2.2(i)  for all prior  Fiscal
Years; and

                  (ii)  second,  to  the  Members  in  proportion  to and to the
extent of the excess,  if any, of (x) the aggregate  amount of Loss allocated to
each such Member for all prior Fiscal Years pursuant to Section 3.3.1,  over (y)
the aggregate  amount of Operating  Profit  allocated to such Member pursuant to
this Section 3.2.1(ii) for all prior Fiscal Years; and

                  (iii) the remainder,  eighty (80%) percent to IMMUNOMEDICS and
twenty (20%) percent to GOLDENBERG.

                  Section 3.2.2  Gain on Disposition.  Any item of gain that is
taken into account in computing  Profit for any Fiscal Year that is attributable
to the sale or  exchange  of any asset by the  Company or by IBC  Pharmaceutical
(other than a sale or exchange made in the ordinary course of business) shall be
allocated as follows:

                  (i)  first, to the Members in proportion to and to the extent
of the excess,  if any, of (x) the  aggregate  amount of Loss  allocated to such
Member  pursuant to Section  3.3.2 for all Fiscal Years  (including  the current
Fiscal  Year),  over (y) the sum of the  aggregate  amount of Operating  Profits
allocated to such Member pursuant to Section 3.2.1(i) for all prior Fiscal Years
and the  aggregate  amount of gain  allocated  to such  Member  pursuant to this
Section 3.2.2(i) for all prior Fiscal Years;

                  (ii) then to  GOLDENBERG  until the  aggregate  amount of gain
allocated to him pursuant to this Section  3.2.2(ii)  with respect to such asset
equals  twenty-five (25%) percent of the book value of such asset at the time of
sale or  exchange,  provided  that the  aggregate  amount of gain  allocated  to
GOLDENBERG pursuant to this Section 3.2.2(ii) does not exceed $4,662,000; and

                                       A-7


                  (iii) the remainder,  eighty (80%) percent to IMMUNOMEDICS and
twenty (20%) percent to GOLDENBERG.

         Section 3.3  Allocation of Loss.

                  Section 3.3.1  General Rule. Loss for any Fiscal Year shall be
allocated eighty percent to IMMUNOMEDICS and twenty (20%) percent to GOLDENBERG.

                  Section 3.3.2  Special  Limitation.   Loss  allocated  to  the
Members  for any Fiscal  year  pursuant  to Section  3.3.1  shall not exceed the
maximum amount of such Loss that can be so allocated  without causing any Member
to have an Adjusted  Capital  Account Deficit at the end of such Fiscal Year. In
the event  some but not all of the  Members  would  have such  Adjusted  Capital
Account  Deficits as a  consequence  of an  allocation of Loss for a Fiscal Year
pursuant to Section  3.3.1,  the  limitation  set forth in the first sentence of
this Section  3.3.2 shall be applied so as to allocate  the maximum  permissible
amount of such Loss to each Member  under  Section  1.704-1(b)(2)(ii)(d)  of the
Treasury Regulations.

         Section 3.4 Unanticipated  State of Facts. If an unanticipated state of
facts arises  (including a change in the federal income tax treatment of company
allocations),  the allocations and  determinations  governed by this Article III
shall be made by the  Members  so as to carry out as nearly as  practicable  the
purposes of this  Article  III,  namely,  to give  cumulative  recognition  when
allocating  tax  items  to  differences  between  the  Fiscal  Year  in  which a
transaction or item is recognized for purposes of determining Profit or Loss and
the taxable year in which it affects taxable income.

         Section 3.5  Special  Allocations.  The  following  special allocations
 shall be  made in the following order:

                  Section  3.5.1  Minimum Gain  Chargeback.  Except as otherwise
provided by Section  1.704-2(f) of the Treasury  Regulations,  if there is a net
decrease in the Company  Minimum  Gain  during any Fiscal  Year,  there shall be
allocated to each Member (before any other allocation is made under this Section
3.5)  items of  income  and  gain  for such  Fiscal  Year  (and,  if  necessary,
subsequent  periods) in proportion  to, and to the extent of, an amount equal to
such  Member's  share of the net  decrease in Company  Minimum  Gain during such
Fiscal Year  (determined in accordance  with Section  1.704-2(g) of the Treasury
Regulations).  The items to be allocated  for any Fiscal year under this Section
3.5.1 shall be  determined  in  accordance  with  Section  1.704-2(j)(2)  of the
Treasury Regulations.

                                       A-8


                  Section  3.5.2  Member  Minimum  Gain  Chargeback.  Except  as
otherwise  provided by Section  1.704-2(i)(4)  of the Treasury  Regulations,  if
during  any Fiscal  Year there is a net  decrease  in the  Member  Minimum  Gain
attributable to a Member  Nonrecourse Debt, there shall be allocated (before any
allocation  for such  Fiscal  Year is made under this  Section  3.5 (other  than
Section  3.5.1))  to  each  Member  with a  share  of the  Member  Minimum  Gain
attributable  to such  Member  Nonrecourse  Debt (as  determined  under  Section
1.704-2(i)(5)  of the  Treasury  Regulations)  items of income and gain for such
Fiscal Year (and, if necessary,  for subsequent  Fiscal Years) in proportion to,
and to the extent of such Member's share of the net decrease  during such Fiscal
Year in the Member Minimum Gain  attributable  to such Member  Nonrecourse  Debt
(determined under Section 1.704-2(i)(4) of the Treasury Regulations).  The items
to be allocated for any Fiscal Year under this Section 3.5.2 shall be determined
in accordance with Section 1.704-2(j)(2) of the Treasury Regulations.

                  Section  3.5.3   Qualified   Income  Offset.   If  any  Member
unexpectedly receives any adjustments, allocations or distributions described in
Section  1.704-1(b)(2)(ii)(d)(4),  Section  1.704-1(b)(2)(ii)(d)(5)  or  Section
1.704-1(b)(2)(ii)(d)(6)  of the  Treasury  Regulations  during any Fiscal  Year,
there shall be allocated  (before any  allocation is made under this Section 3.5
(other than  Sections  3.5.1 or Section  3.5.2)) to such Member items of Company
income and gain for such  Fiscal  Year (and,  if  necessary,  subsequent  Fiscal
Years) in an amount and manner  sufficient to eliminate,  to the extent required
by the Treasury Regulations, the Adjusted Capital Account Deficit of such Member
as quickly as possible,  provided  that an  allocation  pursuant to this Section
3.5.3  shall be made only if and to the extent  that such  Member  would have an
Adjusted  Capital Account Deficit after all other  allocations  provided in this
Section 3.5 have been  tentatively made as if this Section 3.5.3 were not in the
Agreement.  Any allocation of income or gain for any Fiscal Year made under this
Section 3.5.3 shall consist of a pro rata portion of each item of Company income
(including gross income) and gain for such period (other than income or gain for
such period allocated under Sections 3.5.1 or 3.5.2).

                  Section 3.5.4 Gross Income  Allocation.  If there is a deficit
balance in the Capital Account of any Member at the end of any Fiscal Year which
is in excess of the amount of such Member's  Deficit  Restoration  Obligation at
that time, each such Member shall be specially allocated items of Company income
and gain in the amount of such excess as quickly as possible,  provided  that an

                                       A-9


allocation  to the Capital  Account of a Member  pursuant to this Section  3.5.4
shall be made only if and to the extent that such Member  would have an Adjusted
Capital Account Deficit in excess of such Deficit  Restoration  Obligation after
all other  allocations  provided  for in this  Section  3.5 have been made as if
Section 3.5.3 and this Section 3.5.4 were not in the Agreement.

                  Section  3.5.5  Section  754  Adjustments.  To the  extent  an
adjustment to the tax basis of any Company asset  pursuant to Section  734(b) or
Section    743(b)   of   the   Code   is    required    pursuant    to   Section
1.704-1(b)(2)(iv)(m)(2)  or  Section  1.704-1(b)(2)(iv)(m)(4)  of  the  Treasury
Regulations  to be taken into  account in  determining  Capital  Accounts as the
result of a  distribution  to a Member in complete  liquidation of such Member's
Interest or as the result of the sale of a Member's Interest, the amount of such
adjustment  to  Capital  Accounts  shall be  treated  as an item of gain (if the
adjustment  increases  the  basis  of the  asset)  or loss  (if  the  adjustment
decreases such basis) and such gain or loss shall be specially  allocated to the
Members in accordance  with their  interests in the Company in the event Section
1.704-1(b)(2)(iv)(m)(2)   of  the  Treasury   Regulations  applies,  or  to  the
distributee  in the  event  Section  1.704-1(b)  (2)(iv)(m)(4)  of the  Treasury
Regulations applies.

                  Section 3.5.6  Nonrecourse Deductions.  Nonrecourse Deductions
for any Fiscal Year shall be allocated as  determined by the Members in a manner
that is consistent  with the  principles of Sections  1.704-1 and 1.704-2 of the
Treasury Regulations.

                  Section 3.5.7  Member  Nonrecourse   Deductions.   Any  Member
Nonrecourse  Deductions for any Fiscal Year shall be allocated to the Member who
bears the economic risk of loss with respect to the Member  Nonrecourse  Debt to
which such Member  Nonrecourse  Deductions are  attributable  in accordance with
Section 1.704-2(i)(1) of the Treasury Regulations.

         Section 3.6 Curative Allocations.  All Regulatory  Allocations shall be
offset either with other Regulatory  Allocations or with special  allocations of
items in the nature of income,  gain,  expense, or loss pursuant to this Section
3.6.  The  Company  shall  make  such  offsetting  special  allocations  in  its
discretion so that,  after such  offsetting  allocations are made, each Member's
Capital Account balance is, to the extent possible, equal to the Capital Account
balance such Member would have had if the Regulatory  Allocations  were not part
of the Addendum and all Company items were allocated pursuant to Section 3.2 and
Section 3.3 of the Agreement.  In exercising  its discretion  under this Section
3.6, the Company shall take into account  future  Regulatory  Allocations  that,
although  not yet  made,  are  likely  to offset  other  Regulatory  Allocations
previously made.

         Section 3.7  Allocation of Tax Items.  For federal and state income tax
purposes, Company income gain, loss, deduction and credit (or items thereof) for
any Fiscal Year shall be allocated as follows:

                                      A-10


                  Section 3.7.1  General Rule.   Except  as provided in Sections
3.7.2,  3.7.3 and 3.7.4, all items of income,  gain, loss,  deduction and credit
shall be allocated  in the same manner as the  correlative  items are  allocated
under Sections 3.2 and 3.3.

                  Section 3.7.2 Section 704(c) Considerations.  Items of income,
gain, loss and deduction with respect to any asset contributed to the capital of
the  Company  shall,  solely for income tax  purposes,  be  allocated  among the
Members so as to take account of any  variation  between the  adjusted  basis of
such asset to the  Company for federal  income tax  purposes  and the gross fair
market  value of such asset at the time of  contribution.  In the event the book
value of any asset  contributed to the capital of the Company is revalued on the
Company's books, subsequent allocations of income, gain, loss and deduction with
respect to such asset shall take account of any  variation  between the adjusted
basis of such asset to the Company for federal  income tax purposes and the book
value of such asset immediately following such revaluation in the same manner as
under Section 704(c) of the Code and the Treasury  Regulations  thereunder.  Any
elections  or other  decisions  relating to  allocations  made  pursuant to this
Section  3.7.2  shall  be made by the  Members  in any  manner  that  reasonably
reflects the purposes and intentions of this Agreement.

                  Section 3.7.3 Recapture  Income.  For purposes of deter-mining
the character (as ordinary  income or capital gain) of any taxable income of the
Company,  such portion of the taxable  income of the Company which is treated as
ordinary income attributable to the recapture of depreciation (or cost recovery)
shall,  to the  extent  possible,  be  allocated  among  the  Member  (or  their
successors in interest) in the same  proportions  that the depreciation (or cost
recovery)  deductions  directly  or  indirectly  giving rise to such income were
previously  allocated.  This  Section  3.7.3  shall  not  alter  the  amount  of
allocations to any Member but merely the character of income so allocated.

                  Section 3.7.4  Transfers of Company Interests.   If during any
taxable year of the Company  there is a change in any  Member's  interest in the
Company,  then each Member's  distributive share of each item of Company income,
gain,  loss and deduction shall be determined for federal income tax purposes as
if the  taxable  year of the  Company  closed  on the date of such  change.  For
purposes of this  Section  3.7.4,  a transfer of an interest in the Company made
during the first fifteen (15) days of any calendar  month will be deemed to have
been  effected at the opening of month,  and a transfer made after the fifteenth
day of any calendar month will be deemed to have been effected at the opening of
the following month.

                                      A-11



                                   ARTICLE IV

                                  DISTRIBUTIONS

         Section 4.1  Distributions.   Except  as  otherwise provided by Section
6.1,

                  Section 4.1.1 Distributable.  Distributable cash (as the same
is determined by the Company at its sole  discretion) at the close of any Fiscal
Year shall be distributed  eighty (80%) percent to IMMUNOMEDICS and twenty (20%)
percent to GOLDENBERG.

                  Section 4.1.2  Special Limitation. Distributions made pursuant
to Section 4.1.1 shall not exceed the maximum amount that can be so made without
causing any Member to have an deficit Capital Account balance. In the event some
but not all of the  Members  would  have such  deficits  as a  consequence  of a
distribution  pursuant to Section  4.1.1,  the limitation set forth in the first
sentence of this Section 4.1.2 shall be applied on a  Member-by-Member  basis so
as to distribute the maximum permissible amount to each Member.

         Section 4.2 [ Intentionally Omitted ]

         Section 4.3  Amounts Withheld.

                  Section  4.3.1  Amounts  Withheld  on Behalf  of  Governmental
Authority.   All  amounts  withheld  pursuant  to  the  Code  and  the  Treasury
Regulations  or any  provision  of any  state or local tax law or the law of any
foreign   country  or   subdivision   thereof   with  respect  to  any  payment,
distribution,  or  allocation  to the Company or the Members shall be treated as
amounts  distributed  to the Members  pursuant to Section 4.1 or Section 4.2 for
all purposes  under this  Agreement.  The Company is authorized to withhold from
distributions, or with respect to allocations, to the Members and to pay over to
any federal, state, or local government or foreign government or any subdivision
thereof  any  amounts  required  to be so  withheld  pursuant to the Code or any
provisions of any other federal,  state,  or local law or the law of any foreign
country or  subdivision  thereof and shall  allocate such amounts to the Members
with respect to which such amount was withheld.

         Section 4.4  Liability  for  Distributions.   A  Member  who receives a
distribution  for the Company shall have no liability under the Act or any other
applicable  law for the amount of the  distribution  after the expiration of six
(6) years  from the date of the  distribution  unless an action to  recover  the
distribution  from such member is commenced prior to the expiration of such six-
(6-) year period and an adjudication of liability against such Member is made in
such action.

                                      A-12


         Section 4.5  Distributions  in  Kind.  The Company shall have the right
to compel a Member to accept a distribution of any asset in kind, whether or not
the percentage of the asset distributed to it exceeds a percentage of that asset
which is equal to the  percentage in which it shares in  distributions  from the
Company.


                                    ARTICLE V


                                BOOKS OF ACCOUNT;
                      FINANCIAL STATEMENTS; FISCAL MATTERS

         Section 5.1  Accounting, Books and Records.

                  Section 5.1.1  Required  Records.   The  Members shall keep on
site at the principal place of business of the Company each of the following:

                  (i)  separate books of account for the Company which shall
show a true and accurate record of all costs and expenses incurred,  all charges
made,  all  credits  made and  received,  and all income  derived in  connection
therewith and the operation thereof accordance with this Agreement;

                  (ii) a current list of the full name and last known  business,
residence, or mailing address of each Member, both past and present;

                  (iii)  a  copy  of   the  Articles  of  Organization  and  all
 amendments thereto, together with executed copies of any powers of attorney
 pursuant to which any amendment has been executed;

                  (iv) copies of the Company's federal,  state, and local income
tax returns and reports, if any, for the three most recent years;

                  (v)  copies of this Agreement; and

                  (vi)  any  minutes  of meetings of the Members and any written
consents  obtained  from  Members  pursuant  to  Section  407 of the Act and the
Agreement regarding action taken by Members without a meeting.

                  Section 5.1.2  Accounting  Matters.   The  books of account of
the Company shall be kept on a calendar year basis in accordance  with generally
accepted  accounting  principles.  The Company shall, to the extent permitted by

                                      A-13


the Code, compute its income (and items thereof) for federal income tax purposes
on the basis of the calendar year using the cash method of accounting.

                  Section 5.1.3  Access  to  Records.   After  giving reasonable
advance  written notice to the Company  stating under oath the purpose  thereof,
any Member may inspect and review the Company Records for any proper purpose and
may, at the Member's expense, have the Company make copies of any portion or all
of the Company Records. A proper purpose shall mean a purpose reasonably related
to such person's interest as a Member. Unless the Company agrees otherwise,  all
Member  access to the  Company  Records  must take place  during  the  Company's
regular business hours. The Company may impose additional  reasonable conditions
and restrictions on Members' access to the Company Records, including specifying
the amount of advance  notice a Member  must give and the  charges  imposed  for
copying.

         Section 5.2  Reports.

                  Section 5.2.1  Generally.   The Treasurer of the Company shall
be responsible for causing the  preparation of financial  reports of the Company
and the coordination of financial matters of the Company with the Accountants.

                  Section 5.2.2  Annual Reports. Within one hundred eighty (180)
days after the close of each Fiscal Year,  the Company shall send to each Person
who was a Member at any time during the Fiscal Year then ended the  consolidated
balance  sheet  of the  Company  as of the  close of such  Year and the  related
consolidated  statements  of income,  changes in Members'  equity and changes in
financial  position for such Fiscal Year. Such  consolidated  balance sheets and
statements need not be audited.

         Section 5.3  Tax Matters.

                  Section 5.3.1 Tax Elections.  IMMUNOMEDICS shall,  without any
further  consent of the Members being  required,  make any and all elections for
federal,  state,  local,  and foreign tax purposes,  including any election,  if
permitted  by  applicable  law (i) to adjust the basis of the  Company's  assets
pursuant  to  Sections  754,  734(b)  and  743(b)  of the  Code  (or  comparable
provisions  of state,  local or  foreign  law);  (ii) to extend  the  statute of
limitations for assessment of tax deficiencies  against the Members with respect
to adjustments to the Company's  federal,  state,  local or foreign tax returns;
and (iii) to the extent  provided in Sections  6221 through 6231 of the Code and
similar  provisions of federal,  state,  local, or foreign law, to represent the
Company  and the  Members  before  taxing  authorities  or courts  of  competent

                                      A-14

jurisdiction  in tax  matters  affecting  the  Company  or the  Members in their
capacities as Members, and to file any tax returns and execute any agreements or
other documents relating to or affecting such tax matters,  including agreements
or other  documents  that bind the Members  with  respect to such tax matters or
otherwise affect the rights of the Company and the Members.

                  Section 5.3.2  Tax Information. The Company shall use its best
efforts to send, within ninety (90) days after the close of each Fiscal Year, to
each Person who was a Member at any time during the Fiscal Year then ended, such
tax  information  (including  a  Schedule  K-1) as  shall be  necessary  for the
preparation  by such Person of his or her federal and state  income tax returns,
and any other tax return  required by any  jurisdiction  in which the Company is
formed or qualified to conduct business.

         Section 5.4 Tax Matters  Partner.  IMMUNOMEDICS  shall serve as the tax
matters  partner of the Company within the meaning of Section  6231(a)(7) of the
Code  and the  Treasury  Regulations  promulgated  thereunder  for  purposes  of
representing the Company in administrative  proceedings  relating to the federal
income tax  treatment of items of Company  income,  gain,  loss,  deduction,  or
credit.  In its capacity as the tax matters partner of the Company,  such Member
shall have all authority  granted to a tax matters partner by the Code and shall
have the  right,  at  Company  expense,  to retain  professional  assistance  in
connection with any audit of the Company by the Service.

                                      A-15



                                   ARTICLE VI

                         TAX AND FINANCIAL CONSEQUENCES
                          OF DISSOLUTION OF THE COMPANY

         Section 6.1 Winding Up. Upon the occurrence of a Dissolution Event, the
Company shall  continue  solely for the purposes of winding up its affairs in an
orderly  manner,  liquidating  its  assets,  and  satisfying  the  claims of its
creditors and Members,  and no Member shall take any action that is inconsistent
with,  or not necessary to or  appropriate  for, the winding up of the Company's
business and affairs, provided that all covenants contained in the Agreement and
this  Addendum and  obligations  provided for in the Agreement and this Addendum
shall  continue to be fully  binding upon the Members  until such time as all of
the Company's assets have been distributed  pursuant to this Section 6.1 and the
Articles of Dissolution  have been filed in accordance with the Act. The Members
shall be  responsible  for  supervising  the winding up and  dissolution  of the
Company, which winding up and dissolution shall be completed as expeditiously as
possible.  The Members shall take full account of the Company's  liabilities and
assets and shall  cause its assets or the  proceeds  from the sale  thereof  (as
determined  pursuant to Section 6.8), to the extent sufficient  therefor,  to be
applied  and  distributed,  to the  maximum  extent  permitted  by  law,  in the
following order:

                  (i)  first, to creditors (including Members who are creditors,
to  the  extent  otherwise  permitted  by  law)  in  satisfaction  of all of the
Company's  debts and other  liabilities  (whether  by  payment  or the making of
reasonable  provision for payment  thereof),  other than  liabilities  for which
reasonable  provision for payment has been made and liabilities for distribution
to members under Section 507 or Section 509 of the Act;

                  (ii)  second, except as provided in this Agreement, to Members
and  former  Members  of  the  Company  in   satisfaction   of  liabilities  for
distribution under Sections 507 or 509 of the Act; and

                  (iii)  the balance, if any,  to the Members in accordance with
the  positive  balance  in  Capital   Accounts,   after  giving  effect  to  all
contributions, distributions and allocations for all periods.

No Member shall  receive  additional  compensation  for any  services  performed
pursuant to this Section 6.1.

         Section  6.2  Compliance  with  Certain  Requirements  of  Regulations;
Deficit Capital  Accounts.  In the event the Company is "liquidated"  within the
meaning of Regulations Section 1.704-1(b)(2)(ii)(g),  (i) distributions shall be
made  pursuant to this  Section 6.2 to the  Members  who have  positive  Capital

                                      A-16

Accounts in  compliance  with  Section  1.704-1(b)(2)(ii)(B)(2)  of the Treasury
Regulations.  If any Member has a deficit  balance in his Capital Account (after
giving effect to all contributions, distributions and allocations for all Fiscal
Years,  including the Fiscal Year during which such  liquidation  occurs),  such
Member shall have no obligation to make any  contribution  to the capital of the
Company with respect to such deficit, and such deficit shall not be considered a
debt owed to the Company or to any other Person for any purpose  whatsoever.  In
the discretion of the Liquidator,  a pro rata portion of the distributions  that
would otherwise be made to the Members pursuant to this Article VI may be:

                  (i) distributed to a trust  established for the benefit of the
         Members for the  purposes of  liquidating  Company  assets,  collecting
         amounts owed to the Company,  and paying any  contingent  or unforeseen
         liabilities  or obligations  of the Company and  distributed  from such
         trust to the Members from time to time, in the reasonable discretion of
         the Liquidator,  in the same  proportions as the amount  distributed to
         such trust by the Company would otherwise have been  distributed to the
         Members pursuant to Section 6.1; or

                  (ii)  withheld  to  provide  a  reasonable reserve for Company
         liabilities  (contingent  or  otherwise)  and to reflect the unrealized
         portion  of any  installment obligations  owed to the Company, provided
         that such withheld amounts shall be  distributed to the Members as soon
         as practicable.

         Section 6.3 Deemed Distribution and Recontribution. Notwithstanding any
other  provision  of this  Article  VI, in the event the  Company is  liquidated
within the meaning of Section 1.706-1  (b)(2)(ii)(g) of the Treasury Regulations
but no Dissolution Event has occurred, the Company shall not be liquidated,  the
Company's debts and other liabilities  shall not be paid or discharged,  and the
Company's  affairs shall not be wound up. Instead,  soley for federal income tax
purposes,  the Company  shall,  to the extent  required by  applicable  Treasury
Regulations,  be deemed to have  contributed its assets in-kind to a new limited
liability  company,  which shall be deemed to have taken such assets  subject to
all debts of the  Company  and other  liabilities,  in  exchange  for all of the
ownership  interests in that new company.  Immediately  thereafter,  the Company
shall, to the extent required by applicable Treasury  Regulations,  be deemed to
have distributed such interests in-kind to the Members.

         Section 6.4  Rights of Members.   Except  as otherwise provided in this
Agreement,  each  Member  shall look solely to the assets of the Company for the

                                      A-17

return  of his  Capital  Contribution  and has no right or  power to  demand  or
receive  assets other than cash from the  Company.  If the assets of the Company
remaining  after payment or discharge of the debts or liabilities of the Company
are insufficient to return such Capital Contribution,  the Members shall have no
recourse against the Company or any other Member.

         Section 6.5 Notice of Dissolution/Termination.

                  Section 6.5.1  In  the  event  a Dissolution Event occurs, the
Liquidator  shall,  within thirty (30) days  thereafter,  provide written notice
thereof to each of the  Members and to all other  parties  with whom the Company
regularly  conducts  business and shall publish notice thereof in a newspaper of
general  circulation  in each  place in which  the  Company  regularly  conducts
business.

                  Section 6.5.2  Upon  completion  of  the  distribution  of its
assets as provided in this Article VI, the Company shall be terminated,  and the
Liquidator  shall cause the filing of the  Articles of  Dissolution  pursuant to
Section 705 of the Act and shall take all such other actions as may be necessary
to terminate the Company.

         Section 6.6  Allocations  During  Period  of  Liquidation.   During the
period commencing on the first day of the Fiscal Year during which a Dissolution
Event  occurs and  ending on the date on which all of the assets of the  Company
have been distributed to the Members pursuant to Section 6.1), the Members shall
continue to share Profits, Losses, gain, loss and other items of Company income,
gain, loss or deduction in the manner provided in Article III.

         Section 6.7  Certain Arrangements Relating to Liquidation.

                  Section  6.7.1  Appointment.  At the time  that a  Dissolution
Event  first  occurs,  IMMUNOMEDICS  shall  appoint  a  Person  to  oversee  the
liquidation of the Company.

                  Section 6.7.2  Fees.  The  Company  is  authorized  to  pay  a
reasonable  fee to the Liquidator  for his services  performed  pursuant to this
Article VI and to reimburse the Liquidator for his reasonable costs and expenses
incurred in performing those services.

         Section 6.8  Form of Liquidating Distributions.  For purposes of making
distributions  required by Section 6.1, the Liquidator may determine  whether to
distribute all or any portion of the Company's  assets in-kind or to sell all or
any portion of such assets and distribute the proceeds therefrom.

                                      A-18



                                                                       EXHIBIT A



                                MEMBERSHIP ROSTER


   Name of Member                                                      Address

IMMUNOMEDICS, INC.                                      300 American Road
                                                        Morris Plains, NJ 07950


DAVID M. GOLDENBERG






                                                                       EXHIBIT B

                      MEMBERS INITIAL CAPITAL CONTRIBUTIONS


   Name of Member                                                    $ Amount

IMMUNOMEDICS, INC.                                                   $18,648,000


DAVID M. GOLDENBERG                                                  $         0