RESTATED CERTIFICATE OF INCORPORATION
                                       OF
                       AMERICAN BIOGENETIC SCIENCES, INC.

It is hereby certified that:

           1.  The  present  name of the  Corporation  (hereinafter  called  the
"Corporation") is American  Biogenetic  Sciences,  Inc., which is the name under
which the  Corporation  was  originally  incorporated.  The date of  filing  the
original  Certificate of  Incorporation of the Corporation with the Secretary of
State of the State of Delaware is September 1, 1983.

           2.  The  provisions  of  the  Certificate  of  Incorporation  of  the
Corporation, as heretofore amended and/or supplemented,  are hereby restated and
integrated into the single instrument  without further amendment and without any
discrepancy  between the  provisions  of the  Certificate  of  Incorporation  as
heretofore  amended  and  supplemented  and the  provisions  of the said  single
instrument hereinafter set forth.

           3. The Board of  Directors of the  Corporation  has duly adopted this
Restated Certificate of Incorporation  pursuant to the provisions of Section 245
of the General Corporation Law of the State of Delaware in the form set forth as
follows:






                     "RESTATED CERTIFICATE OF INCORPORATION
                                       OF
                       AMERICAN BIOGENETIC SCIENCES, INC.
                                    * * * * *

           1. The name of the Corporation is

              AMERICAN BIOGENETIC SCIENCES, INC.

           2. The address of its  registered  office in the State of Delaware is
No. 100 West Tenth Street, in the City of Wilmington,  County of New Castle. The
name of its registered agent at such address is The Corporation Trust Company.
   
           3. The nature of the business or purposes to be conducted or promoted
is to  engage in any  lawful  act or  activity  for  which  corporations  may be
organized under the General Corporation Law of Delaware.

           4. The aggregate  number of shares which the  Corporation  shall have
authority to issue is 53,000,000,  of which (i) 50,000,000 shares,  having a par
value of $.001 per  share,  shall be Class A Common  Stock,  and (ii)  3,000,000
shares, having a par value of $.001 per share, shall be Class B Common Stock.

           The following sets forth the relative rights, powers, preferences and
limitations of the shares of each class of stock.

               (a) The holders of Class A Common  Stock and the holders of Class
B Common  Stock shall be entitled to the same rights and  privileges,  and shall
share equally, share and share alike, in the distribution of any funds which the
Board of Directors may declare or set aside or pay out as






dividends,  and shall share equally,  share and share alike, in the distribution
of any and all  dividends  and in the  distribution  of  assets  in the event of
liquidation,  whether  voluntary  or  involuntary,  and after the payment of all
debts of the Corporation,  and shall be alike in all other respects, except that
each  holder of Class B Common  Stock  shall be  entitled  to ten votes for each
share of Class B Common  Stock held by such  holder,  and each holder of Class A
Common  Stock  shall be  entitled  to one vote for each  share of Class A Common
Stock held by such  holder.  The holders of the Class A Common Stock and Class B
Common Stock shall vote as one class.

               (b) Each share of Class B Common Stock may be converted  into one
share of Class A Common Stock at the option of the holder thereof.

               (c) No person  holding  shares of Class B Common  Stock of record
(hereinafter called a "Class B Holder") may transfer,  and the Corporation shall
not register the  transfer of, such shares of Class B Common  Stock,  as Class B
Common  Stock,  whether  by sale,  assignment,  gift,  bequest,  appointment  or
otherwise,  except to a Permitted Transferee, and upon any attempted transfer of
shares not  permitted  hereunder  said  shares of Class B Common  Stock shall be
converted into Class A Common Stock.  A Permitted  Transferee  shall mean,  with
respect to each person from time to time shown as the record holder of shares of
Class B Common  Stock:  

                              (i) a trust  principally  for the  benefit  of the
Class B Stockholder; and

                              (ii) a  partnership  or  corporation a majority of
the beneficial ownership of which is owned by the Class B Stockholder.

               (d)  Notwithstanding  anything to the contrary set forth  herein,
any Class B Holder may pledge such Holder's  shares of Class B Common Stock to a
pledgee pursuant to a bona fide pledge of such shares as collateral security for
indebtedness due to the pledgee, provided that such


                                       -2-




shares shall not be  transferred to or registered in the name of the pledgee and
shall  remain  subject  to the  provisions  of this  Article  4. In the event of
foreclosure or other similar action by the pledgee, such pledged shares of Class
B Common Stock may only be converted into shares of Class A Common Stock.

               (e) At any time when the number of outstanding  shares of Class B
Common Stock as reflected on the stock transfer books of the  Corporation  falls
below 5% of the  aggregate  number of the issued and  outstanding  shares of the
Class A Common Stock and Class B Common Stock of the  Corporation,  or the Board
of Directors and the holders of a majority of the outstanding  shares of Class B
Common  Stock  approve the  conversion  of all of the Class B Common  Stock into
Class A Common  Stock,  then,  immediately  upon the  occurrence  of either such
event,  the  outstanding  shares of Class B Common Stock shall be converted into
shares of Class A Common Stock. In the event of such a conversion,  certificates
formerly representing outstanding shares of Class B Common Stock shall thereupon
and  thereafter  be deemed  to  represent  the like  number of shares of Class A
Common Stock.

               (f) Shares of Class B Common  Stock  shall be  registered  in the
names of the beneficial  owners  thereof and not in "street" or "nominee"  name.
For this  purpose,  a  "beneficial  owner" of any shares of Class B Common Stock
shall mean a person who, or an entity which, possess the power, either singly or
jointly,  to direct the voting or  disposition of such shares.  The  Corporation
shall  note  on the  certificates  for  shares  of  Class  B  Common  Stock  the
restrictions on transfer and registration of transfer imposed by this Article 4.

               (g)  The  Corporation  shall,  at all  times,  reserve  and  keep
available out of authorized but unissued shares of Class A Common Stock,  solely
for the purpose of effecting the conversion of


                                       -3-




Class B Common  Stock,  such  number of shares of Class A Common  Stock as shall
from time to time be  sufficient  to effect the  conversion  of all  outstanding
shares of Class B Common Stock.

           5. The Corporation is to have perpetual existence.

           6. In  furtherance  and not in limitation of the powers  conferred by
statute, the Board of Directors is expressly authorized to make, alter or repeal
the by-laws of the Corporation.

           7.  Elections of Directors  need not be by written  ballot unless the
by-laws of the Corporation shall so provide.

           Meetings of  stockholders  may be held within or without the State of
Delaware,  as the by-laws may provide.  The books of the Corporation may be kept
(subject  to any  provision  contained  in the  statutes)  outside  the State of
Delaware at such place or places as may be  designated  from time to time by the
Board of Directors or in the by-laws of the Corporation.

           8. The  Corporation  reserves  the right to amend,  alter,  change or
repeal any provision  contained in this  Certificate  of  Incorporation,  in the
manner now or hereafter  prescribed by statute,  and all rights  conferred  upon
stockholders herein are granted subject to this reservation.

           9. No Director of the Corporation  shall be liable to the Corporation
or any of its  stockholders for monetary damages for breach of fiduciary duty as
a Director,  except for liability (1) for any breach of the  Director's  duty of
loyalty to the Corporation or its stockholders, (2) for acts or omissions not in
good faith or which involve  intentional  misconduct  or a knowing  violation of
law, (3) under Section 174 of the Delaware  General  Corporation Law, or (4) for
any transaction from which the Director derived an improper  personal  benefit."

Signed on July 29, 1996

                                              /s/ Alfred J. Roach
                                              ---------------------------
                                              Alfred J. Roach, Chairman of the
                                              Board of Directors


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