IGEN INTERNATIONAL, INC. 
                                  EXHIBIT 3.2



                           CERTIFICATE OF DESIGNATION

                                       OF

                 SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                       OF

                            IGEN INTERNATIONAL, INC.

                        (Pursuant to Section 151 of the
                       Delaware General Corporation Law)


     IGEN INTERNATIONAL, INC., a corporation organized and existing under the
General Corporation Law of the State of Delaware (hereinafter called the
"Company"), hereby certifies that the following resolution was adopted by the
Board of Directors of the Corporation as required by Section 151 of the General
Corporation Law at a meeting duly called and held on November 2, 1996:

          RESOLVED, that pursuant to the authority granted to and vested in the
     Board of Directors of the Company in accordance with the provisions of its
     Certificate of Incorporation, the Board of Directors hereby creates a
     series of Preferred Stock, par value $.001 per share, of the Company and
     hereby states the designation and number of shares, and fixes the relative
     designations and the powers, preferences and rights, and the
     qualifications, limitations and restrictions thereof (in addition to the
     provisions set forth in the Certificate of Incorporation of the Company,
     which are applicable to the Preferred Stock of all classes and series), as
     follows:

          Series A Junior Participating Preferred Stock:



          SECTION 1.  DESIGNATION AND AMOUNT.  Six Hundred Thousand (600,000)
shares of Preferred Stock, $.001 par value, are designated "Series A Junior
Participating Preferred Stock" with the designations and the powers, preferences
and rights, and the qualifications, limitations and restrictions specified
herein (the "Junior Preferred Stock").  Such number of shares may be increased
or decreased by resolution of the Board of Directors; provided, that no decrease
shall reduce the number of shares of Junior Preferred Stock to a number less
than the number of shares then outstanding plus the number of shares reserved
for issuance upon

                                       1.

 
the exercise of outstanding options, rights or warrants or upon the conversion
of any outstanding securities issued by the Company convertible into Junior
Preferred Stock.

          SECTION 2.  DIVIDENDS AND DISTRIBUTIONS.

          (A) Subject to the rights of the holders of any shares of any series
     of Preferred Stock (or any similar stock) ranking prior and superior to the
     Junior Preferred Stock with respect to dividends, the holders of shares of
     Junior Preferred Stock, in preference to the holders of Common Stock, par
     value $.001 per share (the "Common Stock"), of the Company, and of any
     other junior stock, shall be entitled to receive, when, as and if declared
     by the Board of Directors out of funds legally available for the purpose,
     quarterly dividends payable in cash on the first day of March, June,
     September and December in each year (each such date being referred to
     herein as a "Quarterly Dividend Payment Date"), commencing on the first
     Quarterly Dividend Payment Date after the first issuance of a share or
     fraction of a share of Junior Preferred Stock, in an amount per share
     (rounded to the nearest cent) equal to the greater of (a) $l.00 or (b)
     subject to the provision for adjustment hereinafter set forth, 100 times
     the aggregate per share amount of all cash dividends, and 100 times the
     aggregate per share amount (payable in kind) of all non-cash dividends or
     other distributions, other than a dividend payable in shares of Common
     Stock or a subdivision of the outstanding shares of Common Stock (by
     reclassification or otherwise) declared on the Common Stock since the
     immediately preceding Quarterly Dividend Payment Date or, with respect to
     the first Quarterly Dividend Payment Date, since the first issuance of any
     share or fraction of a share of Junior Preferred Stock.  In the event the
     Company shall at any time declare or pay any dividend on the Common Stock
     payable in shares of Common Stock, or effect a subdivision or combination
     or consolidation of the outstanding shares of Common Stock (by
     reclassification or otherwise than by payment of a dividend in shares of
     Common Stock) into a greater or lesser number of shares of Common Stock,
     then in each such case the amount to which holders of shares of Junior
     Preferred Stock were entitled immediately prior to such event under clause
     (b) of the preceding sentence shall be adjusted by multiplying such amount
     by a fraction, the numerator of which is the number of shares of Common
     Stock outstanding immediately after such event and the denominator of which
     is the number of shares of Common Stock that were outstanding immediately
     prior to such event.

          (B) The Company shall declare a dividend or distribution on the Junior
     Preferred Stock as provided in paragraph (A) of this Section immediately
     after it declares a dividend or distribution on the Common Stock (other
     than a dividend payable in shares of Common Stock); provided that, in the
     event no dividend or distribution shall have been declared on the Common
     Stock during the period between any Quarterly Dividend Payment Date and the
     next subsequent Quarterly Dividend Payment Date, a dividend of $1.00 per
     share on the Junior Preferred

                                       2.

 
     Stock shall nevertheless be payable on such subsequent Quarterly Dividend
     Payment Date.

          (C) Dividends shall begin to accrue and be cumulative on outstanding
     shares of Junior Preferred Stock from the Quarterly Dividend Payment Date
     next preceding the date of issue of such shares, unless the date of issue
     of such shares is prior to the record date for the first Quarterly Dividend
     Payment Date, in which case dividends on such shares shall begin to accrue
     from the date of issue of such shares, or unless the date of issue is a
     Quarterly Dividend Payment Date or is a date after the record date for the
     determination of holders of shares of Junior Preferred Stock entitled to
     receive a quarterly dividend and before such Quarterly Dividend Payment
     Date, in either of which events such dividends shall begin to accrue and be
     cumulative from such Quarterly Dividend Payment Date.  Accrued but unpaid
     dividends shall not bear interest.  Dividends paid on the shares of Junior
     Preferred Stock in an amount less than the total amount of such dividends
     at the time accrued and payable on such shares shall be allocated pro rata
     on a share-by-share basis among all such shares at the time outstanding.
     The Board of Directors may fix a record date for the determination of
     holders of shares of Junior Preferred Stock entitled to receive payment of
     a dividend or distribution declared thereon, which record date shall be not
     more than 60 days prior to the date fixed for the payment thereof.

          SECTION 3.  VOTING RIGHTS.  The holders of shares of Junior Preferred
     Stock shall have the following voting rights:

          (A) Subject to the provision for adjustment hereinafter set forth,
     each share of Junior Preferred Stock shall entitle the holder thereof to
     100 votes on all matters submitted to a vote of the stockholders of the
     Company.  In the event the Company shall at any time declare or pay any
     dividend on the Common Stock payable in shares of Common Stock, or effect a
     subdivision or combination or consolidation of the outstanding shares of
     Common Stock (by reclassification or otherwise than by payment of a
     dividend in shares of Common Stock) into a greater or lesser number of
     shares of Common Stock, then in each such case the number of votes per
     share to which holders of shares of Junior Preferred Stock were entitled
     immediately prior to such event shall be adjusted by multiplying such
     number by a fraction, the numerator of which is the number of shares of
     Common Stock outstanding immediately after such event and the denominator
     of which is the number of shares of Common Stock that were outstanding
     immediately prior to such event.

          (B) Except as otherwise provided herein, in any other Certificate of
     Designation creating a series of Preferred Stock or any similar stock, or
     by law, the holders of shares of Junior Preferred Stock and the holders of
     shares of Common Stock and any other capital stock of the Company having
     general voting rights shall vote together as one class on all matters
     submitted to a vote of stockholders of the Company.

                                       3.

 
     (C) Except as set forth herein, or as otherwise provided by law, holders of
     Junior Preferred Stock shall have no special voting rights and their
     consent shall not be required (except to the extent they are entitled to
     vote with holders of Common Stock as set forth herein) for taking any
     corporate action.

          SECTION 4.  CERTAIN RESTRICTIONS.

          (A) Whenever quarterly dividends or other dividends or distributions
     payable on the Junior Preferred Stock as provided in Section 2 are in
     arrears, thereafter and until all accrued and unpaid dividends and
     distributions, whether or not declared, on shares of Junior Preferred Stock
     outstanding shall have been paid in full, the Company shall not:

               (I) declare or pay dividends, or make any other distributions, on
     any shares of stock ranking junior (either as to dividends or upon
     liquidation, dissolution or winding up) to the Junior Preferred Stock;

               (II) declare or pay dividends, or make any other distributions,
     on any shares of stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Junior Preferred Stock,
     except dividends paid ratably on the Junior Preferred Stock and all such
     parity stock on which dividends are payable or in arrears in proportion to
     the total amounts to which the holders of all such shares are then
     entitled;

               (III)  redeem or purchase or otherwise acquire for consideration
     shares of any stock ranking junior (either as to dividends or upon
     liquidation, dissolution or winding up) to the Junior Preferred Stock,
     provided that the Company may at any time redeem, purchase or otherwise
     acquire shares of any such junior stock in exchange for shares of any stock
     of the Company ranking junior (either as to dividends or upon dissolution,
     liquidation or winding up) to the Junior Preferred Stock; or

               (IV) redeem or purchase or otherwise acquire for consideration
     any shares of Junior Preferred Stock, or any shares of stock ranking on a
     parity with the Junior Preferred Stock, except in accordance with a
     purchase offer made in writing or by publication (as determined by the
     Board of Directors) to all holders of such shares upon such terms as the
     Board of Directors, after consideration of the respective annual dividend
     rates and other relative rights and preferences of the respective series
     and classes, shall determine in good faith will result in fair and
     equitable treatment among the respective series or classes.

          (B) The Company shall not permit any subsidiary of the Company to
     purchase or otherwise acquire for consideration any shares of stock of the
     Company unless the Company could, under paragraph (A) of this Section 4,
     purchase or otherwise acquire such shares at such time and in such manner.

                                       4.

 
          SECTION 5.  REACQUIRED SHARES.  Any shares of Junior Preferred Stock
     purchased or otherwise acquired by the Company in any manner whatsoever
     shall be retired and cancelled promptly after the acquisition thereof.  All
     such shares shall upon their cancellation become authorized but unissued
     shares of Preferred Stock and may be reissued as part of a new series of
     Preferred Stock subject to the conditions and restrictions on issuance set
     forth herein, in the Restated Certificate of Incorporation, or in any other
     Certificate of Designation creating a series of Preferred Stock or any
     similar stock or as otherwise required by law.

          SECTION 6.  LIQUIDATION, DISSOLUTION OR WINDING UP.  Upon any
     liquidation, dissolution or winding up of the Company, no distribution
     shall be made (1) to the holders of shares of stock ranking junior (either
     as to dividends or upon liquidation, dissolution or winding up) to the
     Junior Preferred Stock unless, prior thereto, the holders of shares of
     Junior Preferred Stock shall have received $100 per share, plus an amount
     equal to accrued and unpaid dividends and distributions thereon, whether or
     not declared, to the date of such payment, provided that the holders of
     shares of Junior Preferred Stock shall be entitled to receive an aggregate
     amount per share, subject to the provision for adjustment hereinafter set
     forth, equal to 100 times the aggregate amount to be distributed per share
     to holders of shares of Common Stock, or (2) to the holders of shares of
     stock ranking on a parity (either as to dividends or upon liquidation,
     dissolution or winding up) with the Junior Preferred Stock, except
     distributions made ratably on the Junior Preferred Stock and all such
     parity stock in proportion to the total amounts to which the holders of all
     such shares are entitled upon such liquidation, dissolution or winding up.
     In the event the Company shall at any time declare or pay any dividend on
     the Common Stock payable in shares of Common Stock, or effect a subdivision
     or combination or consolidation of the outstanding shares of Common Stock
     (by reclassification or otherwise than by payment of a dividend in shares
     of Common Stock) into a greater or lesser number of shares of Common Stock,
     then in each such case the aggregate amount to which holders of shares of
     Junior Preferred Stock were entitled immediately prior to such event under
     the proviso in clause (1) of the preceding sentence shall be adjusted by
     multiplying such amount by a fraction the numerator of which is the number
     of shares of Common Stock outstanding immediately after such event and the
     denominator of which is the number of shares of Common Stock that were
     outstanding immediately prior to such event.

          SECTION 7.  CONSOLIDATION, MERGER, ETC.  In case the Company shall
     enter into any consolidation, merger, combination or other transaction in
     which the shares of Common Stock are exchanged for or changed into other
     stock or securities, cash and/or any other property, then in any such case
     each share of Junior Preferred Stock shall at the same time be similarly
     exchanged or changed into an amount per share, subject to the provision for
     adjustment hereinafter set forth, equal to 100 times the aggregate amount
     of stock, securities, cash and/or any other property (payable in kind), as
     the case may be, into which or for which each share of Common Stock is
     changed or exchanged.  In the event the

                                       5.

 
     Company shall at any time declare or pay any dividend on the Common Stock
     payable in shares of Common Stock, or effect a subdivision or combination
     or consolidation of the outstanding shares of Common Stock (by
     reclassification or otherwise than by payment of a dividend in shares of
     Common Stock) into a greater or lesser number of shares of Common Stock,
     then in each such case the amount set forth in the preceding sentence with
     respect to the exchange or change of shares of Junior Preferred Stock shall
     be adjusted by multiplying such amount by a fraction, the numerator of
     which is the number of shares of Common Stock outstanding immediately after
     such event and the denominator of which is the number of shares of Common
     Stock that were outstanding immediately prior to such event.

          SECTION 8.  NO REDEMPTION.  The shares of Junior Preferred Stock shall
     not be redeemable.

          SECTION 9.  RANK.  The Junior Preferred Stock shall rank, with respect
     to the payment of dividends and the distribution of assets, junior to all
     series of any other class of the Company's Preferred Stock.

          SECTION 10.  AMENDMENT.  The Certificate of Incorporation of the
     Company shall not be amended in any manner which would materially alter or
     change the powers, preferences or special rights of the Junior Preferred
     Stock so as to affect them adversely without the affirmative vote of the
     holders of at least two-thirds of the outstanding shares of Junior
     Preferred Stock, voting together as a single class.

     IN WITNESS WHEREOF, the undersigned have executed this certificate as of
November 2, 1996.


                              /s/ Richard J. Massey 
                              -----------------------------------------
                              RICHARD J. MASSEY, PH.D.
                              President and Chief Operating Officer



                              /s/ Andrei M. Manoliu
                              -----------------------------------------
                              ANDREI M. MANOLIU
                              Secretary

                                       6.