Exhibit 10.1

                           INDEMNIFICATION AGREEMENT

     THIS  INDEMNIFICATION  AGREEMENT  (this  "Agreement") is entered into as of
October  26,  2001,  by  and  between  IGEN  International,   Inc.,  a  Delaware
corporation (the "Company"), to and for the benefit of Jacob N. Wohlstadter (the
"Indemnified Party").
                                   WITNESSETH:

          WHEREAS, the Company previously engaged the Indemnified Party to
perform services as an independent contractor to the Company for periods both
prior to and from and after November 30, 1995; and
          WHEREAS, it was contemplated in connection with the Indemnified
party's performance of services for the Company that the Company would provide
indemnification for the Indemnified Party;
          WHEREAS, the Company has previously executed and delivered an
indemnification agreement relating to, among other things, indemnification of
the Indemnified Party and JW Consulting Services, L.L.C. by the Company in
connection with the performance of services to the Company from and after
November 30, 1995; and
          WHEREAS, the parties desire to execute and deliver this Agreement to
provide indemnification, in accordance with the terms hereof, for services
rendered prior to November 30, 1995;
          NOW, THEREFORE, in consideration of the premises and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereby agree as follows:

          1.       Definitions.
                   -----------

          Capitalized terms used herein shall have the meaning defined in the
recitals set forth above or shall have the meaning defined herein. In addition,
the following terms when used with initial capitalization shall have the
following meanings:

                   "Claim" shall mean any threatened, pending or completed
claim, action, demand, suit or proceeding, whether civil, criminal,
administrative or investigative, and whether formal or informal.





                   "Damages" shall mean any losses, liabilities, damages
(including consequential, special and incidental), claims, demands, judgments,
settlements, fines, penalties, expenses and costs (including Defense Costs).

                   "Defense Costs" shall mean any costs, charges, bonds, fees
and expenses, including reasonable attorneys' fees and fees of experts and
consultants, reasonably incurred in the investigation, defense or prosecution of
any Claim.

                   "Person" shall mean an individual, partnership, limited
partnership, corporation, company, association, business trust, limited
liability company, trust, unincorporated association, joint venture, or
governmental entity, authority or agency.

                   "Third Party" shall mean any trustee, receiver, creditor,
contractor, vendor or service provider to the Company or any other person doing
business or otherwise associated with the Company.

          2.       INDEMNIFICATION BY THE COMPANY; LIMITATIONS.

                   (a) Third Party Claims. The Company shall defend, indemnify
                       ------------------
and hold harmless the Indemnified Party from and against any and all Damages
asserted against or suffered or incurred by the Indemnified Party in connection
with any Claim brought by any Person, including any Third Party, arising from,
relating to or resulting from any alleged acts or omissions of the Indemnified
Party related to or arising out of the performance or non-performance of
services to or for the benefit of the Company in periods prior to November 30,
1995.

                   (b) Reimbursement for and Advancement of Defense Costs. The
                       --------------------------------------------------
Company shall reimburse the Indemnified Party for any and all Defense Costs
relating to a Claim subject to indemnification under Section 2(a) incurred by
                                                     ------------
the Indemnified Party in accordance with Section 3. Defense Costs incurred by
                                         ---------
the Indemnified Party shall be paid by the Company in advance of the final
disposition of such Claim, within 20 days after the receipt by the Company of a
statement or statements from the Indemnified Party requesting such advance
payment. In addition, the Indemnified Party may request and receive an advance
for anticipated Defense Costs by submitting to the Company a statement or
statements which shall reasonably evidence the anticipated Defense Costs. Each
statement submitted pursuant to this Section shall include





an undertaking by the Indemnified Party to repay any previously advanced Defense
Costs in the event that it is ultimately determined that the Indemnified Party
is not entitled to indemnification under Section 2(c).
                                         ------------

                   (c) Limitation on Indemnification. Anything to the contrary
                       -----------------------------
herein notwithstanding, the Company shall not be required hereunder to indemnify
the Indemnified Party for any Damages to the extent the underlying Claim arises
from acts or omissions (i) which constitute intentional misconduct of the
Indemnified Party, (ii) which constitute a knowing violation of law by the
Indemnified Party, or (iii) which are specifically prohibited from being
included in an otherwise enforceable indemnification provision or agreement by
the applicable law of the jurisdiction in question.

                   (d) No Duplication of Payments. The Company shall not be
                       --------------------------
liable under this Agreement to make any payment of amounts otherwise
indemnifiable hereunder if and to the extent that the Indemnified Party has
otherwise actually and properly received payment of such amounts under any
insurance policy, contract, agreement or otherwise.

                   (e) Non-exclusivity. Nothing herein shall be deemed to
                       ---------------
diminish or otherwise restrict the Indemnified Party's right to indemnification
under applicable law, or any other agreement, instrument or document, including
any certificate or articles of incorporation, bylaws, limited liability company
agreement or other governing organizational document (including the letter
agreement dated as of November 30, 1995 between the Company and the Indemnified
Party relating to indemnification of the Indemnified Party by the Company in
connection with the Indemnified Party's relationship with Meso Scale
Diagnostics, LLC. (the "MSD INDEMNIFICATION LETTER") and the Indemnification
Agreement, dated as of August 15, 2001, effective as of November 30, 1996, among
the Company, the Indemnified Party and JW Consulting Services, L.L.C. ("JW
CONSULTING") relating to, among other things, indemnification of the Indemnified
Party and JW Consulting by the Company in connection with the performance of
services to the Company from and after November 30, 1995 (the "INDEMNIFICATION
AGREEMENT")).




          3. INDEMNIFICATION PROCEDURES.
             --------------------------
                   (a) Notice of Claim. The Indemnified Party shall promptly
notify the Company in writing of any Claim in respect of which indemnification
could be sought under this Agreement. Such notice shall be given with reasonable
promptness after the Indemnified Party becomes aware of such Claim; provided,
however, that failure to give prompt notice shall not adversely affect or
disqualify any claim for indemnification hereunder except to the extent the
Company is materially prejudiced thereby. Such notice shall specify the nature
of the Claim, the amount of Damages (to the extent such amount is then known to
the Indemnified Party at such time and without prejudice to any right the
Indemnified Party may have to thereafter be indemnified in any greater amount)
and all material information regarding such Claim which is then known to the
Indemnified Party.
                   (b) Control of Defense by the Indemnified Party. Following
                       -------------------------------------------
delivery of the notice described in Section 3(a), the Indemnified Party shall
                                    ------------
keep the Company fully informed and, unless the Company exercises the right of
control set forth in Section 3(c), shall use its reasonable efforts to contest
                     ------------
and defend such Claim with its own legal counsel and present any defense
reasonably suggested by the Company or its counsel. To the extent the
Indemnified Party controls the defense of such Claim, the Company shall
reimburse or pay the Defense Costs as they are incurred, or advance such Defense
Costs as requested in accordance with Section 2(b). If, in accordance with
                                      ------------
Section 3(c), the Company properly elects to assume and control defense of such
- ------------
Claim, then the Company shall immediately reimburse the Indemnified Party for
any unreimbursed Defense Costs incurred or paid by, or on behalf of, the
Indemnified Party in connection with the defense of such Claim prior to the
receipt by the Indemnified Party of the Assumption and Acknowledgment Notice (as
such term is defined below) relating to such Claim. If the Company assumes and
controls defense of such Claim, the Indemnified Party shall reasonably cooperate
with the Company in such defense. If the Company does not assume and control
defense of such Claim, the Company shall continue to have the right to
participate in the defense of such Claim (subject to the right of the
Indemnified Party to control the defense of such Claim), at its own expense.

                    (c) Assumption and Control of Defense by the Company.
                        -------------------------------------------------
Subject to Section 3(d), the Company, upon written notice to the Indemnified
Party (the "ASSUMPTION AND ACKNOWLEDGMENT NOTICE") within 30 days after receipt
of the notice described in Section 3(a),
                           ------------




may assume and control, at its own expense, the defense of the Claim with
counsel approved by the Indemnified Party (which approval shall not be
unreasonably withheld or delayed). The Assumption and Acknowledgment Notice
shall notify the Indemnified Party of (i) the Company's intention to assume and
control the defense of such Claim and (ii) the Company's unconditional
acknowledgment of its indemnification liability hereunder for the full amount of
Damages arising under or relating to such Claim (unless and to the extent it is
determined based upon information not theretofore made available to the Company
subsequent to such date that the Company is not liable to indemnify the
Indemnified Party pursuant to Section 2(c)). At all times, the Indemnified Party
                              -------------
shall retain the right to approve all pleadings and other submissions of
whatever kind relating to the Claim prior to their filing or submission (which
approval shall not be unreasonably withheld or delayed), and shall be kept fully
informed of all stages of the Claim.

                   (d) Restrictions on the Company's Ability to Assume and
                       ---------------------------------------------------
Control Defense of the Claim. Notwithstanding anything in Section 3(c) to the
- -----------------------------                             ------------
contrary, the Company shall not be entitled to control the defense of any Claim
if (i) the Company fails to provide the Assumption and Acknowledgment Notice
within 30 days after receipt of the notice contemplated in Section 3(a), (ii)
                                                           ------------
the Indemnified Party has reasonably concluded that there may be legal defenses
available to the Indemnified Party that are different from or in addition to
those available to the Company or (iii) the Company has not employed counsel
satisfactory to the Indemnified Party to assume the defense of such Claim within
a reasonable time after receiving notice of the commencement of such Claim. In
any such case, the Indemnified Party shall be entitled to control the defense of
such Claim and be reimbursed in accordance with Section 2(b). Notwithstanding
                                                ------------
anything contained herein to the contrary, the Indemnified Party may provide
written notice to the Company that the Indemnified Party prefers that the
Company, and therefore directs and instructs the Company to, assume and control
defense of such Claim, in which case the Company will assume and control defense
of such Claim in accordance with Section 3(c), and deliver the Assumption and
                                 ------------
Acknowledgment Notice contemplated by such Section, as promptly as practicable
following receipt of such notice. The Company's assumption of control of the
defense of such Claim pursuant to the preceding sentence shall not constitute an
acknowledgement by the Company of its indemnification liability under this
Agreement.






                   (e) Continued Participation by the Indemnified Party. If the
                       ------------------------------------------------
Company assumes control of the defense of a Claim in accordance with the
provisions of Sections 3(c) or 3(d), the Indemnified Party may notify the
              ---------------------
Company in writing that the Indemnified Party thereafter desires to retain
separate counsel in order to participate in or proceed independently with the
defense of such Claim, at the Indemnified Party's own expense; provided that,
the Indemnified Party shall be reimbursed by the Company for the reasonable fees
and expenses of such counsel incurred by the Indemnified Party if (i) the
Company, in its discretion, provides written authorization to the Indemnified
Party for the employment of such counsel and the reimbursement of such fees and
expenses, or (ii) there are legal defenses available to the Indemnified Party
that are not available to the Company, or counsel representing the Company and
the Indemnified Party, under applicable ethical rules and opinions, would be
required to seek consent to such joint representation of the Company and the
Indemnified Party.

                   (f) Settlement of the Claim. If the Indemnified Party desires
                       ------------------------
to claim indemnification hereunder with respect to the compromise or settlement
of any Claim, as a condition precedent to such indemnification, the Indemnified
Party shall first notify the Company in writing of any firm settlement or
compromise proposal the Indemnified Party receives or intends to make with
respect to such Claim prior to accepting or offering such proposal. The
Indemnified Party shall not settle or compromise any Claim in respect of which
the Indemnified Party is entitled to be indemnified by the Company hereunder
without the prior written consent of the Company, which consent shall not be
unreasonably withheld or delayed. The exercise of any right of consent or
withholding of consent under this Section 3(f) shall not affect, excuse, modify
or relieve the Company of any of its obligations under this Agreement.

           4.     REPRESENTATIONS AND WARRANTIES. The Company hereby represents
                  ------------------------------
and warrants to the Indemnified Party as of the date of execution hereof that:

                   (a) Organization: Good Standing. The Company is a
                       ---------------------------
corporation, duly organized, validly existing and in good standing under the
laws of the State of Delaware, and is duly authorized to transact business and
is in good standing in each jurisdiction where the failure to so qualify would
have a material adverse effect on the performance by the Company of its
obligations hereunder.





                   (b) Authorization. The Company has all requisite corporate
                       -------------
power and authority to execute, deliver and perform its obligations under this
Agreement.

                   (c) Non-Contravention. The execution and delivery by the
                       -----------------
Company of this Agreement and the performance by it of its obligations hereunder
have been duly authorized by all necessary corporate actions and do not and will
not: (i) contravene its certificate of incorporation or by-laws; (ii) conflict
with, result in a breach of or constitute a default under any material contract,
agreement or other instrument to which it is a party or by which it or its
property is bound; or (iii) violate any applicable statute, law, rule,
regulation, writ, injunction, order, decree, judgment or award of any government
authority.

                   (d) Execution and Binding Effect. This Agreement has been
                       ----------------------------
duly executed and delivered on behalf of the Company and constitutes its legal,
valid and binding obligation, enforceable against it in accordance with its
terms.

                   (e) Absence of Conflicts. Except to the extent set forth on
                       --------------------
Schedule 4(e), no litigation, arbitration or other proceeding against the
Company by or before any government authority, court, arbitrator or mediator
with valid jurisdiction is in progress, pending or, to the best knowledge of the
Company, threatened against the Company, which challenges the validity of this
Agreement or that is reasonably likely to have a material adverse effect upon
(i) the Company, (ii) the Company's ability to perform its obligations hereunder
or (iii) the validity or enforceability of this Agreement.

                   (f) Consents and Approvals. The execution and delivery by the
                       ----------------------
Company of this Agreement and the performance by the Company of its obligations
hereunder do not and will not require any approval, consent, permit, license or
other authorization of, or filing or registration with, or any other action by,
any Person (including government approvals) which, as of the date hereof, has
not been duly obtained, made or taken and all such approvals, consents, permits,
licenses, authorizations, filings and registrations have been disclosed to the
Indemnified Party and are in full force and effect and, with respect to
government approvals, are final and non-appealable.


          5.      EVENTS OF DEFAULT
                  -----------------

                   (a) Events of Default. It shall constitute an event of
                       -----------------
default hereunder (each, an "EVENT OF DEFAULT") with respect to the Company if
any of the following shall occur:
                           (i)     the Company fails to pay all Damages covered
by a valid obligation to provide indemnification hereunder within 30 days after
(A) the Company's receipt of written notice that either a judgment or order in
respect of the Claim giving rise to such Damages has been rendered by a
competent governmental authority and such judgment or order has become final
and not subject to any further appeal, (B) the reaching of a final settlement or
compromise in relation to such Claim in accordance with Section 3(f) hereof, or
                                                        ------------
(C) the Company waives, whether by affirmative action or inaction, its right to
contest such Claim in any judicial proceeding in accordance with Section 3;

                            (ii) the Company fails to use reasonable efforts to
cause the removal (by insurance, bond or otherwise) of any lien or encumbrance
of record on the assets of the Indemnified Party arising from, or in connection
with, any Claim which gives rise to a valid obligation to provide
indemnification hereunder within 60 days of receipt of written notice from the
Indemnified Party of the existence of such lien or encumbrance;

                            (iii) the Company fails to pay, in accordance with
Section 2(b), any Defense Costs incurred by the Indemnified Party in connection
- ------------
with the contest or defense of any Claim with respect to which the Company is
responsible pursuant to Section 3; or
                        ---------

                            (iv) the Company breaches any other term or
provision of this Agreement and such breach cannot be cured or is not cured
within 30 days after notice by the Indemnified Party to the Company of such
breach.

                   (b) Remedies. If an Event of Default occurs, the Company
                       --------
shall be considered to have breached this Agreement and, at any time thereafter,
the Indemnified Party may bring suit against the Company to recover any unpaid
amounts or obtain such other relief available to the Indemnified Party at law or
in equity. In the event the Indemnified Party is successful, in whole or in
part, in obtaining any such unpaid amounts or other relief contemplated in this
Section 5(b), the Company shall reimburse the Indemnified Party for all costs
- ------------
and expenses associated with the efforts of the Indemnified Party to obtain such
relief.





          6. TERMINATION. This Agreement shall continue until, and terminate
             -----------
upon the later of: (a) the expiration of any applicable statute of limitations
with respect to those matters which the Indemnified Party is granted rights of
indemnification or advancement of expenses hereunder or (b) the final
termination of all pending proceedings in respect of which the Indemnified Party
is granted rights of indemnification or advancement of expenses hereunder and of
any proceeding commenced by the Indemnified Party pursuant to Section 5(b) of
                                                              ------------
this Agreement relating thereto.

         7.  MISCELLANEOUS.
             -------------

                   (a) Headings; Interpretation. The headings in this Agreement
                       ------------------------
are intended solely for convenience of reference and shall be given no effect in
the construction or interpretation of this Agreement. All terms defined in this
Agreement include the plural as well as the singular. Whenever the words
"include," "includes" and "including" are used in this Agreement, they are
deemed to be followed by the words "without limitation."

                   (b) Severability. If any provision of this Agreement is
                       ------------
for any reason found to be unenforceable, the remainder of this Agreement will
continue in full force and effect.

                   (c) Entire Agreement; Amendments. This Agreement constitutes
                       ----------------------------
a complete statement of all of the agreements among the parties as of the date
hereof with respect to the matters contemplated hereby, supersedes all prior
agreements, understandings, negotiations and discussions, whether oral or
written, between them with respect thereto and cannot be changed or terminated
orally. Notwithstanding the foregoing, nothing in this Agreement shall be deemed
to alter, amend, conflict with or otherwise affect the rights and obligations of
the Company and the Indemnified Party pursuant to the MSD Indemnification Letter
or the Indemnification Agreement or any other written agreement between the
Company and the Indemnified Party. The parties hereto have not relied on any
statements, representations, warranties or covenants, whether oral or written,
other than those set forth in this Agreement.

                   (d) No Waiver. The failure of a party to insist upon
                       ---------
strict adherence to any term of this Agreement on any occasion shall not be
considered a waiver or deprive that party of the right to insist later on
adherence thereto, or thereafter to insist upon strict adherence to that





term or any other term of this Agreement. Any waiver must be in writing and
signed by the party against whom enforcement is sought in order to be effective.

                   (e) Assignment: Successors. This Agreement may not be
                       ----------------------
transferred or assigned by the Company (including by merger or operation of law)
without the prior written consent of the Indemnified Party (which consent shall
not be unreasonably withheld or delayed). Without limiting the availability of
any remedies at law or in equity, any attempted transfer or assignment by the
Company without the prior written consent of the Indemnified Party (which
consent shall not be unreasonably withheld or delayed) will be void. To the
extent this Agreement or any rights or obligations hereunder are transferred or
assigned in a manner that is permitted by this Agreement, this Agreement shall
be binding upon all assigns and successors in interest of the parties hereto
(including any transferee or assignee of all or substantially all of such
party's assets and any successor by merger or operation of law).

                   (f) Third Party Beneficiaries. The provisions of this
                       -------------------------
Agreement shall not confer any rights or remedies upon any person or entity,
other than (i) the Indemnified Party and the heirs, executors, legal
representatives and assigns of the Indemnified Party, as the case may be, and
(ii) the Company and its permitted assigns and successors in interest.

                   (g) Notices. All notices, requests, demands and other
                       -------
communications under this Agreement shall be in writing and shall be deemed to
have been duly given if (i) delivered by hand and receipt of which is
acknowledged by the party to whom said notice or other communication shall have
been directed, (ii) mailed by certified or registered mail with postage prepaid,
on the third business day after the date on which it is so mailed, (iii) sent by
overnight courier, when received and signed for at the appropriate address
listed below, or (iv) sent by facsimile, at the time when received in legible
form by the recipient at the appropriate address listed below and when the
recipient has been requested to acknowledge receipt of the entire telecopier or
facsimile transmission upon the sending or receiving of the acknowledgment of
receipt (which acknowledgment the recipient will promptly give) when received if
sent by overnight courier, addressed as follows:

                            (A)     If to the Indemnified Party:
                                    9905D Gable Ridge Terrace
                                    Rockville, MD 20850
                                    Facsimile: (301) 947-7240






                           (B)     If to the Company:
                                   IGEN International, Inc.
                                   16020 Industrial Drive
                                   Gaithersburg, MD 20877
                                   Attn:   Richard J. Massey, Ph.D.
                                   Facsimile: (301) 208-3799

or to such other address as a party may specify from time to time by notice
hereunder.

                   (h) Governing Law. This Agreement shall be governed by and
                       -------------
construed in accordance with the laws of the State of Delaware (without
reference to the conflicts of laws principles thereof). The parties hereby
consent to the non-exclusive jurisdiction of the state and federal courts of the
State of Delaware.

                   (i) Counterparts. This Agreement may be executed and
                       ------------
delivered in one or more counterparts, each of which shall be an original but
all of which shall together constitute a single agreement.











IN WITNESS WHEREOF, the parties have executed and delivered this Agreement as of
the date first set forth above.



                         IGEN INTERNATIONAL, INC.

                         By:      /s/Richard J. Massey________________
                                  ------------------------------------
                         Name:    Richard J. Massey___________________
                                  ------------------------------------
                         Title:   President___________________________
                                  ------------------------------------




                         /s/Jacob N. Wohlstadter______________________
                         ---------------------------------------------
                         Jacob N. Wohlstadter






                                  SCHEDULE 4(E)
                             OUTSTANDING LITIGATION

1. IGEN International, Inc. V. Roche Diagnostics GmBH, D.Md. No. PJM 97-3461
2. F. Hoffman-La Roche, Ltd. V. IGEN International, Inc., et al., D.Del. No.
   1:98cv00318
3. Brown Simpson Strategic Growth Fund, L.P., et al., v. Wohlstadter, et al.,
   Cir. Ct. Montgomery Cty., MD C.A. No. 218263V
4. Paskowitz v. Wohlstadter, et al., Cir. Ct. Montgomery Cty., MD, C.A. No.
   219321V