THESE  SECURITIES HAVE NOT BEEN REGISTERED  UNDER THE SECURITIES ACT OF 1933, AS
AMENDED OR ANY STATE  SECURITIES  LAWS. THEY MAY NOT BE SOLD OR OFFERED FOR SALE
EXCEPT  PURSUANT TO AN EFFECTIVE  REGISTRATION  STATEMENT  AS TO THE  SECURITIES
UNDER  SAID  ACT AND  ANY  APPLICABLE  STATE  SECURITIES  LAWS OR AN  APPLICABLE
EXEMPTION FROM SUCH REGISTRATION REQUIREMENTS.
                                                                     
                                             Right to Purchase Shares of Class A
                                             Common Stock of American Biogenetic
                                             Sciences, Inc.

No. WC[  ]                                                    May 20, 1998

                            ------------------------
                          Common Stock Purchase Warrant

            American Biogenetic Sciences, Inc., a Delaware corporation having an
address at 1375 Akron Street,  Copiague, New York 11726 (the "Company"),  hereby
certifies that for good and valuable consideration,  the receipt and sufficiency
of which are hereby acknowledged,  [______________________] having an address at
[_____________________________________]   ("Purchaser")  or  any  other  Warrant
Holder (as defined  herein) is entitled,  on the terms and  conditions set forth
below, to purchase from the Company at any time after May 19, 1999 and ending at
the Expiration  Time up to  [_________________________________]  ([______]) (the
"Designated  Amount")  fully  paid and  nonassessable  shares  of Class A Common
Stock, $.001 par value, of the Company together with any associated Common Stock
Purchase  Rights  (the  "Common  Stock")  at  the  Purchase  Price  (hereinafter
defined),  as such  number of shares  and  Purchase  Price  may be  adjusted  as
provided below and pursuant to Section 5 herein.

            The Designated  Amount shall be reduced on the one year  anniversary
of the  date  hereof  by the  product  of (x) the  Designated  Amount  and (y) a
fraction the numerator of which is the Initial Outstanding  Principal Amount (as
such term is defined in the Debentures (the "Debentures")  issued by the Company
to the Purchaser pursuant to the Securities  Subscription  Agreement dated as of
the  date  hereof  (the  "Agreement"))  of  Purchaser's   Debentures  minus  the
Outstanding  Principal Amount (as such term is defined in the Debentures) of the
Purchaser's  Debentures on the one year  anniversary  of the date hereof and the
denominator of which is the Initial Outstanding  Principal Amount of Purchaser's
Debentures.

            1.    Definitions.

                  (a) the term  "Expiration  Time" shall mean 5:00 p.m. New York
                  Time on May 19, 2003.





                  (b) the term  "Fair  Market  Value"  shall  mean  the  closing
                  trading  price of the Common Stock on the NASDAQ Stock Market,
                  the American  Stock  Exchange or the New York Stock  Exchange,
                  whichever is the principal  trading exchange or market for the
                  Common  Stock  (the   "Principal   Market")  on  the  date  of
                  determination  (or if not  traded  on such  date,  on the last
                  trading  date on which  traded  prior to such date) or, if the
                  Common  Stock is not  listed or  admitted  to  trading  on any
                  national  securities  exchange  or quoted in the NASDAQ  Stock
                  Market on a basis  for  which  closing  price  information  is
                  available,  the average of the closing bid and asked prices as
                  furnished  by  any  New  York  Stock   Exchange   member  firm
                  reasonably  selected from time to time by the Company for that
                  purpose,  or, if the Common Stock is not listed or admitted to
                  trading on any national  securities  exchange or quoted on the
                  NASDAQ Stock market or traded over-the-counter and the average
                  price cannot be determined  as  contemplated  above,  the fair
                  market  value  of the  Common  Stock  shall  be as  reasonably
                  determined in good faith by the Company's Board of Directors.

                  (c) the term "Warrant  Holder" shall mean the Purchaser or any
                  assignee  of all or any  portion of this  Warrant at any given
                  time.

                  (d) the term "Warrant  Shares" shall mean the shares of Common
                  Stock or  other  securities  issuable  upon  exercise  of this
                  Warrant.

                  (e) the term "Purchase Price" shall mean $1.9141.

                  (f) other terms used herein which are defined in the Agreement
                  or the  Registration  Rights  Agreement  dated  as of the date
                  hereof  (the  "Registration  Rights  Agreement"),  or  in  the
                  Debentures, shall have the same meanings herein as therein. In
                  the  event  of  a  conflict  in  any  such   definition,   the
                  definitions  shall be applied in the following  order:  first,
                  the  Debentures;   second,  the  Agreement;   and  third,  the
                  Registration Rights Agreement.

                                      - 2 -










            2.    Exercise of Warrant.

                  This Warrant may be exercised by Warrant  Holder,  in whole or
            in part, at any time and from time to time, after May 19, 1999 until
            the Expiration Time by surrender of this Warrant,  together with the
            Purchase  Price  and form of  subscription  at the end  hereof  duly
            executed by Warrant Holder,  to the Company at its principal office.
            In the event that the Warrant is not  exercised in full,  the number
            of Warrant  Shares shall be reduced by the number of Warrant  Shares
            for which this Warrant is exercised and the Company, at its expense,
            shall  forthwith  issue and  deliver to or upon the order of Warrant
            Holder a new Warrant of like tenor in the name of Warrant  Holder or
            as Warrant  Holder (upon payment by Warrant Holder of any applicable
            transfer taxes) may request, reflecting the Warrant Shares remaining
            subject  to this  Warrant.  In the  event  of an  adjustment  to the
            Warrant Shares or Purchase Price pursuant to Section 5 hereof,  this
            Warrant  (including any  replacement  Warrants) may still reflect on
            its  face  the  Warrant  Shares  and  Purchase  Price  as if no such
            adjustments had been made (but such adjustments  shall  nevertheless
            remain effective).

            3.    Delivery of Stock Certificates.

                  (a) Subject to the terms and  conditions of this  Warrant,  as
            soon as practicable after the exercise of this Warrant in full or in
            part, and in any event within three (3) trading days thereafter, the
            Company at its expense (including,  without limitation,  the payment
            by it of any applicable  issue taxes) will cause to be issued in the
            name of and delivered to Warrant Holder,  or as Warrant Holder (upon
            payment  by Warrant  Holder of any  applicable  transfer  taxes) may
            lawfully  direct,  a certificate or  certificates  for the number of
            fully  paid  and  non-assessable  shares  of  Common  Stock to which
            Warrant Holder shall be entitled on such exercise, together with any
            other stock or other  securities or property  (including cash, where
            applicable)  to which Warrant Holder is entitled upon such exercise.
            Any shares issued  hereunder shall, at the request of Warrant Holder
            and if available to the Company,  be delivered by the Company to the
            Warrant Holder in an electronic format (e.g. via DWAC).

                  (b) This Warrant may not be exercised as to fractional  shares
            of Common Stock. In the event that the exercise of this Warrant,  in
            full or in part,  would  result in the  issuance  of any  fractional
            share of  Common  Stock,  then,  in lieu of such  fractional  share,
            Warrant  Holder  shall be  entitled to cash equal to the Fair Market
            Value of such  fractional  share on the date of the  exercise of the
            Warrant.

            4.    Covenants of the Company.

                  (a) The  Company  shall use its  reasonable  best  efforts  to
            insure that a  Registration  Statement  under the Act  covering  the
            resale or other  disposition of the Warrant Shares by Warrant Holder
            is effective as provided in the Registration Rights Agreement.

                                      - 3 -








                  (b)  The  Company  shall  take  all   necessary   actions  and
            proceedings as may be required and permitted by applicable law, rule
            and regulation,  including,  without  limitation the notification of
            NASDAQ,  for the legal and valid  issuance  of this  Warrant and the
            Warrant Shares to the Warrant Holder under this Warrant.

                  (c) From the date  hereof  through the last date on which this
            Warrant is exercisable,  the Company shall take all steps reasonably
            necessary  and within its  control to insure  that the Common  Stock
            remains  listed  on a  Principal  Market  and  shall  not  amend its
            Certificate of  Incorporation or Bylaws so as to constitute a breach
            of the Company's obligations hereunder.

                  (d) The Company shall at all times reserve and keep available,
            solely for issuance and delivery of Warrant Shares  hereunder,  such
            shares of Common  Stock as shall  from time to time be  issuable  as
            Warrant Shares.

                  (e) The Warrant  Shares,  when issued in  accordance  with the
            terms hereof,  will be duly authorized and, when paid for and issued
            in accordance with the terms hereof,  shall be validly issued, fully
            paid and non-assessable. The Company has authorized and reserved for
            issuance to Warrant Holder the requisite  number of shares of Common
            Stock to be issued pursuant to this Warrant.

                  (f) With a view to making  available  to  Warrant  Holder  the
            benefits of Rule 144 promulgated  under the Act ("Rule 144") and any
            other  rule or  regulation  of the SEC that  may at any time  permit
            Warrant  Holder to sell  securities  of the  Company  to the  public
            without registration,  the Company agrees to use its reasonable best
            efforts to:

                        (i) make and keep public information available, as those
                  terms are understood and defined in Rule 144, at all times;

                        (ii) file with the SEC in a timely  manner  all  reports
                  and other documents  required of the Company under the Act and
                  the Exchange Act; and

                        (iii)  furnish to any  Warrant  Holder,  forthwith  upon
                  request,  a written statement by the Company (provided true at
                  the time) that it has complied with the  applicable  reporting
                  and filing  requirements  of the Act and the  Exchange  Act, a
                  copy of the most  recent  annual  or  quarterly  report of the
                  Company,  and such other reports and documents so filed by the
                  Company  as may be  reasonably  requested  to permit  any such
                  Warrant  Holder to take advantage of any rule or regulation of
                  the SEC permitting the selling of any such securities  without
                  registration.

            5.    Adjustment of Exercise Price and Number of Shares.

            The number of, and kind of, securities  purchasable upon exercise of
            this




                                      - 4 -










            Warrant and the Purchase  Price shall be subject to adjustment  from
            time to time as follows:

                  (a)  Subdivisions,  Combinations and Other  Issuances.  If the
            Company  shall at any time  after the date  hereof  but prior to the
            expiration  of this  Warrant  subdivide  or  otherwise  increase its
            outstanding  securities  as to  which  purchase  rights  under  this
            Warrant exist, by split-up,  dividend,  or similar  subdivision,  or
            combine its outstanding securities as to which purchase rights under
            this Warrant  exist,  the number of Warrant  Shares as to which this
            Warrant  is  exercisable  as of the  date  of  such  subdivision  or
            combination  shall, on the record date therefor,  be proportionately
            increased in the case of a subdivision, or proportionately decreased
            in the  case  of a  combination;  however  should  this  Warrant  be
            exercised   prior  to  the   distribution   date   related  to  such
            subdivision, the additional Warrant Shares shall be delivered to the
            Warrant Holder on such distribution  date.  Appropriate  adjustments
            shall also be made to the Purchase Price payable per share,  but the
            aggregate  Purchase  Price  payable for the total  number of Warrant
            Shares  purchasable  under this Warrant as of such date shall remain
            the same.

                  (b) Other Distributions.  If at any time after the date hereof
            the Company  distributes to holders of its Common Stock,  other than
            as part of its  dissolution,  liquidation  or the  winding up of its
            affairs,  any shares of its capital stock,  any securities or rights
            convertible  into Common Stock  ("Common  Stock  Equivalents"),  any
            evidence of  indebtedness  or any of its assets  (other than cash or
            Common Stock)  whether by spin-off or otherwise,  then the number of
            shares of Common Stock for which this Warrant may be exercised shall
            be  increased  as of the record  date (or the date of such  dividend
            distribution if no record date is set) for determining which holders
            of Common  Stock  shall be entitled to receive  such  dividends,  in
            proportion to the increase in the number of outstanding  shares (and
            shares of Common Stock  issuable upon  conversion of all such Common
            Stock Equivalents) of Common Stock as a result of such dividend, and
            the Purchase  Price shall be adjusted so that the  aggregate  amount
            payable  for  the  purchase  of  all  the  Warrant  Shares  issuable
            hereunder  immediately after the record date (or on the date of such
            distribution,  if  applicable)  for such  dividend  shall  equal the
            aggregate amount so payable  immediately before such record date (or
            on the date of such  distribution,  if  applicable);  however should
            this Warrant be exercised prior to the distribution  date related to
            such subdivision,  the additional  Warrant Shares shall be delivered
            to the Warrant Holder on such distribution date.

                  (c) Merger,  etc.  If at any time after the date hereof  there
            shall be a  merger  or  consolidation  of the  Company  with or into
            another entity (with  stockholders of the Company  immediately prior
            to such merger or  consolidation  owning in the aggregate  less than
            50% of the voting power of the ultimate parent  corporation or other
            entity surviving or resulting from such merger or  consolidation) or
            a transfer of all or substantially  all of the assets of the Company
            to another entity, then the Warrant

                                      - 5 -










            Holder  shall be entitled to receive  upon  exercise of this Warrant
            prior to such transfer,  merger or consolidation becoming effective,
            and upon payment of the aggregate Purchase Price then in effect, the
            number of shares or other  securities  or property of the company or
            of  the  successor   corporation   resulting  from  such  merger  or
            consolidation,  which would have been received by Warrant Holder for
            the shares of stock  subject to this  Warrant had this  Warrant been
            exercised  just  prior to such  transfer,  merger  or  consolidation
            becoming effective or to the applicable record date thereof,  as the
            case may be.

                  (d)  Reclassification,  Etc.  If at any  time  after  the date
            hereof there shall be a reorganization  or  reclassification  of the
            securities as to which purchase rights under this Warrant exist into
            the same or a different  number of  securities of any other class or
            classes (other than pursuant to clauses (a) - (c) of this Section 5)
            then the Warrant Holder shall thereafter be entitled to receive upon
            exercise of this  Warrant,  during the period  specified  herein and
            upon  payment of the  Purchase  Price then in effect,  the number of
            shares  or  other   securities  or  property   resulting  from  such
            reorganization or reclassification which would have been received by
            the Warrant  Holder for the shares of stock  subject to this Warrant
            had this Warrant been exercised just prior to such reorganization or
            reclassification.

                  (e) Purchase Price  Adjustment.  In the event that the Company
            issues or sells any (i) Common  Stock or (ii) any  warrants or other
            rights to  subscribe  for or to  purchase,  or any  options  for the
            purchase of, its Common  Stock or any such Common Stock  Equivalents
            (other  than (v)  issuance  of the  Debentures  or the  Warrants  or
            Warrants of like tenor issued in connection with the issuance of the
            Debentures or of shares of Common Stock upon  conversion or exercise
            thereof,  (w) securities  issued or which may be issued  pursuant to
            Company employee, officer, director or consultant stock or option or
            similar   equity-based   compensation   plans   now   or   hereafter
            established,  (x)  contingent  shares  which  may be  issued  by the
            Company  pursuant to its agreement  under which it acquired  Stellar
            Bio Systems, Inc., (y) securities issued in connection with business
            acquisitions,  joint  ventures,  licensing  arrangements  and  other
            non-capital  raising  purposes or (z) shares issued upon exercise of
            Common Stock Equivalents, options, warrants or rights outstanding on
            the date of the Agreement and reflected in the Exchange Act Reports)
            at an  effective  purchase  price per  share  which is less than the
            Purchase Price then in effect, then in such case, the Purchase Price
            in effect  immediately  prior to such issue or sale shall be reduced
            effective  concurrently  with  such  issue  or  sale  to  an  amount
            determined  by  multiplying  the Purchase  Price then in effect by a
            fraction,  (x) the  numerator  of which  shall be the sum of (1) the
            number of shares of Common Stock  outstanding  immediately  prior to
            such issue or sale,  including,  without  duplication,  those shares
            then issuable  pursuant to any provision of the  Debentures  and the
            Warrants  plus (2) the  number of shares of Common  Stock  which the
            aggregate  consideration received by the Company for such additional
            shares would purchase at such Purchase Price and (y) the denominator
            of which shall be the number of shares of Common Stock of the

                                      - 6 -









            Company outstanding  immediately after such issue or sale including,
            without  duplication,  those  shares then  issuable  pursuant to any
            provision of the Debentures and Warrants.

                  The number of shares which may be purchased hereunder shall be
            increased   proportionately  to  any  reduction  in  Purchase  Price
            pursuant to this Section  5(e), so that after such  adjustments  the
            aggregate  Purchase Price payable hereunder for the increased number
            of  shares  shall be the  same as the  aggregate  Purchase  Price in
            effect just prior to such adjustments.

                  (g) If any  Common  Stock  Equivalents,  warrants,  options or
            other rights for which an  adjustment  of Purchase  Price or Warrant
            Shares or other consideration issuable upon exercise of this Warrant
            shall expire  unconverted  or  unexercised  prior to the exercise of
            this  Warrant,  the Purchase  Price and number of Warrant  Shares or
            other  consideration  issuable  upon  exercise of this Warrant shall
            immediately be re-adjusted as if such Common Stock  Equivalents  had
            never been issued.

                  (h) No adjustment  in the Purchase  Price shall be required by
            Section 5 unless  such  adjustment  would  require an increase of at
            least one (1) cent; provided,  however, that any adjustment which is
            not, by reason of this  Section  5(h),  required to be made shall be
            carried forward and taken into account in any subsequent adjustment.
            All  calculations  under  Section  5 shall  be  made to the  nearest
            one-hundredth of a cent or share.

            6.    No Impairment.

                  The  Company  will not, by  amendment  of its  Certificate  of
            Incorporation  or through  any  reorganization,  transfer of assets,
            consolidation,  merger, dissolution,  issue or sale of securities or
            any other voluntary action, avoid or seek to avoid the observance or
            performance  of any of the  terms of this  Warrant,  but will at all
            times in good faith assist in the carrying out of all such terms and
            in the taking of all such action as may be  reasonably  necessary or
            appropriate  in order to protect  the rights of the  Warrant  Holder
            against   impairment.   Without   limiting  the  generality  of  the
            foregoing,  the Company (a) will not  increase  the par value of any
            Warrant Shares above the amount  payable  therefor on such exercise,
            and (b) will take all such action as may be reasonably  necessary or
            appropriate  in order that the Company may validly and legally issue
            fully paid and nonassessable  Warrant Shares on the exercise of this
            Warrant.

                                      - 7 -










            7.    Notice of Adjustments; Notices.

                  Whenever  the Purchase  Price or number of shares  purchasable
            hereunder  shall be  adjusted  pursuant  to  Section 5  hereof,  the
            Company  shall   execute  and  deliver  to  the  Warrant   Holder  a
            certificate setting forth, in reasonable detail, the event requiring
            the  adjustment,  the method by which such adjustment was calculated
            and the Purchase  Price and number of shares  purchasable  hereunder
            after giving  effect to such  adjustment,  and shall cause a copy of
            such certificate to be mailed (by first class mail, postage prepaid)
            to the Warrant Holder.

            8.    Rights As Stockholder.

                  Prior to exercise of this  Warrant,  the Warrant  Holder shall
            not be entitled to any rights as a  stockholder  of the Company with
            respect to the Warrant Shares,  including  (without  limitation) the
            right to vote such shares,  receive dividends or other distributions
            thereon or be  notified of  stockholder  meetings.  However,  in the
            event of any taking by the Company of a record of the holders of any
            class of  securities  for the  purpose of  determining  the  holders
            thereof who are entitled to receive any dividend  (other than a cash
            dividend)  or  other  distribution,  any  right  to  subscribe  for,
            purchase  or  otherwise  acquire any shares of stock of any class or
            any other securities or property, or to receive any other right, the
            Company shall mail to each Warrant Holder, at least 10 days prior to
            the date specified  therein for such record or distribution  date, a
            notice  specifying  the date on which any such record is to be taken
            for (or, if no record date is to be taken therefor, the distribution
            date thereof) the purpose of such dividend,  distribution  or right,
            and the amount  and  character  of such  dividend,  distribution  or
            right.

            9.    Replacement of Warrant.

                  On receipt of evidence reasonably  satisfactory to the Company
            of the loss, theft, destruction or mutilation of the Warrant and, in
            the case of any such loss,  theft or destruction of the Warrant,  on
            delivery  of  an   indemnity   agreement   or  security   reasonably
            satisfactory  in form and amount to the  Company  or, in the case of
            any such mutilation,  on surrender and cancellation of such Warrant,
            the  Company  at its  expense  will  execute  and  deliver,  in lieu
            thereof, a new Warrant of like tenor.

            10.   Specific Enforcement; Consent to Jurisdiction;  Waiver of Jury
                  Trial.

                  (a) The Company and the Warrant Holder  acknowledge  and agree
            that  irreparable  damage  would  occur in the event that any of the
            provisions  of this Warrant were not  performed in  accordance  with
            their specific terms or were otherwise  breached.  It is accordingly
            agreed  that the  parties  shall be  entitled  to an  injunction  or
            injunctions  to prevent or cure  breaches of the  provisions of this
            Warrant and to enforce specifically the terms and provisions hereof,
            this being in addition to any other  remedy to which  either of them
            may be entitled by law or equity.

                                      - 8 -








                  (b) Each of the  Company  and the  Warrant  Holder  hereby (i)
            agree that all actions or proceedings arising directly or indirectly
            from or in connection  with this Warrant shall be litigated  only in
            the  Supreme  Court of the  State of New York or the  United  States
            District Court for the Southern  District of New York located in New
            York County, New York and (ii) consent to the jurisdiction and venue
            of the  foregoing  courts and consent  that any process or notice of
            motion or other  application  to  either  of said  courts or a judge
            thereof may be served inside or outside the State of New York or the
            Southern  District of New York by registered  mail,  return  receipt
            requested,  directed  to the such party at its  address set forth in
            this Warrant (and service so made shall be deemed  complete five (5)
            days after the same has been  posted as  aforesaid)  or by  personal
            service  or in such  other  manner as may be  permissible  under the
            rules of said courts. The parties hereto hereby waive any right to a
            jury  trial in  connection  with  any  litigation  pursuant  to this
            Warrant.

            11.   Entire Agreement; Amendments.

                  This Warrant, the Agreement, the Registration Rights Agreement
            or the Debentures  contain the entire  understanding  of the parties
            with respect to the matters covered hereby and thereby and except as
            specifically  set forth herein and therein,  neither the Company nor
            the Warrant Holder makes any representation,  warranty,  covenant or
            undertaking  with  respect to such  matters.  No  provision  of this
            Agreement  may  be  waived  or  amended  other  than  by  a  written
            instrument  signed by the party against whom enforcement of any such
            amendment or waiver is sought.

            12.   Notices.

                  Unless  otherwise   provided  herein,   any  notice  or  other
            communication to a party hereunder shall be sufficiently given if in
            writing and personally delivered or sent by facsimile with copy sent
            in another manner herein  provided or sent by courier (which for all
            purposes of this Warrant shall include Federal Express, UPS or other
            recognized  overnight  courier) or mailed to said party by certified
            mail, return receipt  requested,  at its address provided for in the
            Subscription Agreement or such other address as either may designate
            for itself in such notice to the other and  communications  shall be
            deemed  to have  been  received  when  delivered  personally  on the
            scheduled  arrival  date  when  sent by next  day or  2-day  courier
            service  or  if  sent  by  facsimile  upon  receipt  of  transmittal
            confirmation  or if sent by mail  three  days  after  deposit in the
            mail.

            13.   Choice of Law and Venue; Waiver of Jury Trial.

                  THIS WARRANT SHALL BE CONSTRUED UNDER THE LAWS OF THE STATE OF
            NEW YORK WITHOUT  REGARD TO PRINCIPLES OF CONFLICTS OF LAW OR CHOICE
            OF LAW (EXCEPT SECTION 5-1401

                                      - 9 -










            OF THE NEW YORK GENERAL  OBLIGATIONS  LAW). The parties hereby agree
            that all actions or proceedings  arising directly or indirectly from
            or in connection  with this Warrant  shall be litigated  only in the
            Supreme Court of the State of New York or the United States District
            Court for the  Southern  District  of New York  located  in New York
            County,  New York. The parties consent to the jurisdiction and venue
            of the  foregoing  courts and consent  that any process or notice of
            motion or other  application  to  either  of said  courts or a judge
            thereof may be served inside or outside the State of New York or the
            Southern  District of New York by registered  mail,  return  receipt
            requested,  directed as provided in Section 13 (and  service so made
            shall be  deemed  complete  five (5)  days  after  the same has been
            posted as aforesaid) or by personal  service or in such other manner
            as may be  permissible  under the rules of said courts.  The parties
            hereto hereby waive any right to jury trial in  connection  with any
            litigation pursuant to this Warrant.








                                     - 10 -










            14.   Miscellaneous.

                  Whenever  the  sense of this  Warrant  requires,  words in the
            singular  shall be deemed to  include  the  plural  and words in the
            plural  shall be deemed to include  the  singular.  If more than one
            company is named  herein,  the  liability of each shall be joint and
            several.  Paragraph  headings are for convenience only and shall not
            affect   the   meaning  of  this   document.   The   invalidity   or
            unenforceability   shall  in  no  way   affect   the   validity   or
            enforceability of any other provisions.



            Dated: May 20, 1998

                                                      AMERICAN BIOGENETIC
                                                      SCIENCES, INC.



                                                      By:  /s/ Josef C. Schoell
                                                         ----------------------
                                                         Name: Josef C. Schoell
                                                         Title: Vice President 
                                                                Finance - CFO

            Attest:


            By:  /s/ Timothy J. Roach
                 --------------------
                  Name: Timothy J. Roach
                  Title:   Treasurer and Secretary





                                     - 11 -









                            FORM OF WARRANT EXERCISE
                   (TO BE SIGNED ONLY ON EXERCISE OF WARRANT)


TO_____________________________


            The   undersigned,   the  holder  of  the  within  Warrant,   hereby
irrevocably  elects to exercise  this Warrant  for, and to purchase  thereunder,
______ shares of Class A Common Stock of American Biogenetic  Sciences,  Inc., a
Delaware   corporation   (the   "Company"),   and  herewith   makes  payment  of
$______________  therefor, and requests that the certificates for such shares be
issued in the name of, and delivered to _____________________, whose address is
__________________________________.


Dated:                                        __________________________________
                                              (Signature must conform to name of
                                              holder as specified on the face of
                                              the Warrant)


                                              __________________________________
                                              (Address)





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                               FORM OF ASSIGNMENT
                   (TO BE SIGNED ONLY ON TRANSFER OF WARRANT)

For value received,  the undersigned hereby sells,  assigns,  and transfers unto
_________________,  whose  address  is  ____________________________  and  whose
social security or taxpayer  identification number is  ________________________,
the right represented by the within Warrant to purchase ______ shares of Class A
Common Stock of American Biogenetic Sciences,  Inc., a Delaware corporation,  to
which the within Warrant relates, and appoints  _______________________ Attorney
to transfer  such right on the books of American  Biogenetic  Sciences,  Inc., a
Delaware corporation, with full power of substitution the premises.


Dated:                                        __________________________________
                                              (Signature must conform to name of
                                              holder as specified on the face of
                                              the Warrant)


                                              __________________________________
                                              (Address)


Signed in the presence of:

__________________________________



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