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                                                                     Exhibit 2.1


                          AGREEMENT AND PLAN OF MERGER
                                OF ANERGEN, INC.,
                             A DELAWARE CORPORATION,
                                       AND
                                 ANERGEN, INC.,
                            A CALIFORNIA CORPORATION


        THIS AGREEMENT AND PLAN OF MERGER dated as of June 30, 1998 (this
"Agreement") is between Anergen, Inc., a Delaware corporation ("Anergen
Delaware"), and Anergen, Inc., a California corporation ("Anergen California").
Anergen Delaware and Anergen California are also referred to herein as the
"Constituent Corporations."

                                    RECITALS

        A. Anergen Delaware is a corporation duly organized and existing under
the laws of the State of Delaware and has authorized capital of 70,000,000
shares, $.001 par value, of which 60,000,000 shares are designated "Common
Stock" and 10,000,000 shares are designated "Preferred Stock." The Preferred
Stock of Anergen Delaware is undesignated as to series, rights, preferences,
privileges or restrictions. As of the date hereof, 1,000 shares of Common Stock
were issued and outstanding, all of which are held by Anergen California, and no
shares of Preferred Stock were issued and outstanding.

        B. Anergen California is a corporation duly organized and existing under
the laws of the State of California and has authorized capital of 50,000,000
shares, no par value, of which 40,000,000 are designated "Common Stock" and
10,000,000 shares are designated "Preferred Stock," of which 1,157,894 shares
are designated as Series A-1 Preferred Stock, 740,740 shares are designated as
Series A-2 Preferred Stock, 3,002,648 shares are designated as Series B
Preferred Stock and 15,000 shares are designated as Series C Preferred Stock. As
of June 30, 1998, 18,891,892 shares of Common Stock were issued and outstanding,
and no shares of Preferred Stock were issued and outstanding.

        C. The Board of Directors of Anergen California has determined that, for
the purpose of effecting the reincorporation of Anergen California in the State
of Delaware, it is advisable and in the best interests of Anergen California and
its shareholders that Anergen California merge with and into Anergen Delaware
upon the terms and conditions herein provided.

        D. The respective Boards of Directors of Anergen Delaware and Anergen
California have approved this Agreement and have directed that this Agreement be
submitted to a vote of their respective sole stockholder and shareholders, and
executed by the undersigned officers.


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        NOW, THEREFORE, in consideration of the mutual agreements and covenants
set forth herein, Anergen Delaware and Anergen California hereby agree, subject
to the terms and conditions hereinafter set forth, as follows:

                                       I.

                                     MERGER

        1.1 Merger. In accordance with the provisions of this Agreement, the
Delaware General Corporation Law and the California Corporations Code, Anergen
California shall be merged with and into Anergen Delaware (the "Merger"), the
separate existence of Anergen California shall cease and Anergen Delaware shall
survive the Merger and shall continue to be governed by the laws of the State of
Delaware, and Anergen Delaware shall be, and is herein also referred to as, the
"Surviving Corporation," and the name of the Surviving Corporation shall be
Anergen, Inc.

        1.2 Filing and Effectiveness. The Merger shall become effective when the
following actions shall have been completed:

                (a) This Agreement and the Merger shall have been adopted and
        approved by the shareholders of each Constituent Corporation in
        accordance with the requirements of the Delaware General Corporation Law
        and the California Corporations Code;

                (b) All of the conditions precedent to the consummation of the
        Merger specified in this Agreement shall have been satisfied or duly
        waived by the party entitled to satisfaction thereof;

                (c) An executed Certificate of Merger or an executed,
        acknowledged and certified counterpart of this Agreement meeting the
        requirements of the Delaware General Corporation Law shall have been
        filed with the Secretary of State of the State of Delaware; and

                (d) An executed Certificate of Merger or an executed,
        acknowledged and certified counterpart of this Agreement meeting the
        requirements of the California Corporations Code shall have been filed
        with the Secretary of State of the State of California.

        The date and time when the Merger shall become effective, as aforesaid,
is herein called the "Effective Date of the Merger."

        1.3 Effect of the Merger. Upon the Effective Date of the Merger, the
separate existence of Anergen California shall cease and Anergen Delaware, as
the Surviving Corporation, (i) shall continue to possess all of its assets,
rights, powers and property as constituted immediately prior to the Effective
Date of the Merger; (ii) shall be subject to all actions previously taken by its
and Anergen California's Boards of Directors; (iii) shall succeed, without other
transfer, to all of the assets, rights, powers and property of Anergen
California in the manner as more fully set forth in Section 259 of the Delaware


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General Corporation Law; (iv) shall continue to be subject to all of its debts,
liabilities and obligations as constituted immediately prior to the Effective
Date of the Merger; and (v) shall succeed, without other transfer, to all of the
debts, liabilities and obligations of Anergen California in the same manner as
if Anergen Delaware had itself incurred them, all as more fully provided under
the applicable provisions of the Delaware General Corporation Law and the
California Corporations Code.


                                       II.

                    CHARTER DOCUMENTS, DIRECTORS AND OFFICERS

        2.1 Certificate of Incorporation. The Certificate of Incorporation of
Anergen Delaware as in effect immediately prior to the Effective Date of the
Merger, a copy of which is attached hereto as Appendix A, shall continue in full
force and effect as the Certificate of Incorporation of the Surviving
Corporation until duly amended in accordance with the provisions thereof and
applicable law.

        2.2 Bylaws. The Bylaws of Anergen Delaware as in effect immediately
prior to the Effective Date of the Merger, shall continue in full force and
effect as the Bylaws of the Surviving Corporation until duly amended in
accordance with the provisions thereof and applicable law.

        2.3 Directors and Officers. The directors and officers of Anergen
California immediately prior to the Effective Date of the Merger shall be the
directors and officers of the Surviving Corporation until their respective
successors shall have been duly elected and qualified or until as otherwise
provided by law, or the Certificate of Incorporation of the Surviving
Corporation or the Bylaws of the Surviving Corporation.


                                      III.

                          MANNER OF CONVERSION OF STOCK

        3.1 Anergen California Common Stock. Upon the Effective Date of the
Merger, each share of Anergen California Common Stock, no par value, issued and
outstanding immediately prior thereto shall, by virtue of the Merger and without
any action by the Constituent Corporations, the holder of such shares or any
other person, be changed and converted into and exchanged for one fully paid and
nonassessable share of Common Stock, $.001 par value, of the Surviving
Corporation.

        3.2 Anergen California Options and Stock Purchase Rights. Upon the
Effective Date of the Merger, the Surviving Corporation shall assume and
continue the stock option plans (including without limitation the 1988 Stock
Option Plan, the 1996 Stock Plan and the 1995 Director Option Plan) and all
other employee benefit plans (including without limitation the 1991 Employee
Stock Purchase Plan and the 1992 Consultant Stock Plan) of Anergen California.
Each outstanding and unexercised option or other right to purchase a security
convertible into Anergen California Common Stock shall become an 


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option or right to purchase or a security convertible into the Surviving
Corporation's Common Stock on the basis of one share of the Surviving
Corporation's Common Stock for each share of Anergen California Common Stock
issuable pursuant to any such option, stock purchase right or convertible
security, on the same terms and conditions set forth in the stock option plans,
other employee benefit plans and/or as provided in the respective option or
stock purchase agreements governing such option stock purchase right or
convertible securities, and at an exercise price per share equal to the exercise
price applicable to any such Anergen California option, stock purchase right or
convertible security at the Effective Date of the Merger. It is the intention of
the parties that the stock options of Anergen California assumed by Anergen
Delaware qualify following the Effective Date of the Merger as incentive stock
options as defined in Section 422 of the Internal Revenue Code of 1986, as
amended (the "Code"), to the extent that the stock options of Anergen California
qualified as incentive stock options immediately prior to the Effective Date of
the Merger. At the Effective Date of the Merger, Anergen California shall assign
to Anergen Delaware any and all rights of repurchase pertaining to shares of
Anergen Delaware Common Stock issued upon exercise of stock options, stock
purchase rights and otherwise. There are no options, purchase rights for or
securities convertible into Preferred Stock of Anergen California.

        A number of shares of the Surviving Corporation's Common Stock shall be
reserved for issuance upon the exercise of options, stock purchase rights or
convertible securities equal to the number of shares of Anergen California
Common Stock so reserved immediately prior to the Effective Date of the Merger.

        3.3 Anergen Delaware Common Stock. Upon the Effective Date of the
Merger, each share of Common Stock, $.001 par value, of Anergen Delaware issued
and outstanding immediately prior thereto shall, by virtue of the Merger and
without any action by Anergen Delaware, the holder of such shares or any other
person, be canceled and returned to the status of authorized but unissued
shares.

        3.4 Certificates. After the Effective Date of the Merger, each
outstanding certificate theretofore representing shares of Anergen California
Common Stock shall be deemed for all purposes to represent the same number of
whole shares of the Surviving Corporation's Common Stock.


                                       IV.

                                     GENERAL

        4.1 Covenants of Anergen Delaware. Anergen Delaware covenants and agrees
that it will, on or before the Effective Date of the Merger:

                (a) Qualify to do business as a foreign corporation in the State
        of California and in connection therewith irrevocably appoint an agent
        for service of process as required under the provisions of Section 2105
        of the California Corporations Code;


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                (b) File any and all documents with the California Franchise Tax
        Board necessary for the assumption by Anergen Delaware of all of the
        franchise tax liabilities of Anergen California; and

                (c) Take such other actions as may be required by the California
        Corporations Code.

        4.2 Further Assurances. From time to time, as and when required by
Anergen Delaware or by its successors or assigns, there shall be executed and
delivered on behalf of Anergen California such deeds and other instruments, and
there shall be taken or caused to be taken by Anergen Delaware and Anergen
California such further and other actions, as shall be appropriate or necessary
in order to vest or perfect in or conform of record or otherwise by Anergen
Delaware the title to and possession of all the property, interests, assets,
rights, privileges, immunities, powers, franchises and authority of Anergen
California and otherwise to carry out the purposes of this Agreement, and the
officers and directors of Anergen Delaware are fully authorized in the name and
on behalf of Anergen California or otherwise to take any and all such action and
to execute and deliver any and all such deeds and other instruments.

        4.3 Abandonment. At any time before the Effective Date of the Merger,
this Agreement may be terminated and the Merger may be abandoned for any reason
whatsoever by the Board of Directors of either Anergen California or Anergen
Delaware, or both, notwithstanding the approval of this Agreement by the
shareholders of Anergen California or by the sole stockholder of Anergen
Delaware, or by both.

        4.4 Amendment. The Boards of Directors of the Constituent Corporations
may amend this Agreement at any time prior to the filing of this Agreement (or
certificate in lieu thereof) with the Secretaries of State of the States of
California and Delaware, provided that an amendment made subsequent to the
adoption of this Agreement by the shareholders of either Constituent Corporation
shall not: (i) alter or change the amount or kind of shares, securities, cash,
property and/or rights to be received in exchange for or on conversion of all or
any of the shares of any class or series thereof of such Constituent
Corporation, (ii) alter or change any term of the Certificate of Incorporation
of the Surviving Corporation to be effected by the Merger, or (iii) alter or
change any of the terms and conditions of this Agreement if such alteration or
change would adversely affect the holders of any class of shares or series
thereof of such Constituent Corporation.

        4.5 Registered Office. The registered office of the Surviving
Corporation in the State of Delaware is located at Corporation Trust Center,
1209 Orange Street, in the City of Wilmington, Delaware 19801, County of New
Castle, and The Corporation Trust Company is the registered agent of the
Surviving Corporation at such address.

        4.6 Agreement. Executed copies of this Agreement will be on file at the
principal place of business of the Surviving Corporation at 301 Penobscot Drive,
Redwood City, CA 94063 and copies thereof will be furnished to any shareholder
of either Constituent Corporation, upon request and without cost.


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        4.7 Governing Law. This Agreement shall in all respects be construed,
interpreted and enforced in accordance with and governed by the laws of the
State of Delaware and, so far as applicable, the merger provisions of the
California Corporations Code.

        4.8 Counterparts. In order to facilitate the filing and recording of
this Agreement, the same may be executed in any number of counterparts, each of
which shall be deemed to be an original and all of which together shall
constitute one and the same instrument.


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        IN WITNESS WHEREOF, this Agreement, having first been approved by
resolutions of the Boards of Directors of Anergen Delaware and Anergen
California, is hereby executed on behalf of each of such two corporations and
attested by their respective officers thereunto duly authorized.

                                        ANERGEN, INC.
                                        a Delaware corporation


                                        By:/s/ BARRY M. SHERMAN
                                           ----------------------------------
                                           Barry M. Sherman, M.D., President

ATTEST:


/s/ DAVID V. SMITH
- ----------------------------------
David V. Smith,
Chief Financial Officer



                                        ANERGEN, INC.
                                        a California corporation


                                        By:/s/ BARRY M. SHERMAN
                                           -----------------------------------
                                           Barry M. Sherman, M.D., President


ATTEST:


/s/ DAVID V. SMITH
- ----------------------------------
David V. Smith,
Chief Financial Officer


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                                  ANERGEN, INC.
                            (California Corporation)

                              OFFICERS' CERTIFICATE

Barry M. Sherman, M.D. and David V. Smith certify that:

        1. They are the President and the Chief Financial Officer, respectively,
of Anergen, Inc., a corporation organized under the laws of the State of
California.

        2. The corporation has authorized two classes of stock, designated
"Common Stock" and "Preferred Stock". There are authorized 40,000,000 shares of
Common Stock and 10,000,000 shares of Preferred Stock, of which 1,157,894 shares
are designated as Series A-1 Preferred Stock, 740,740 shares are designated as
Series A-2 Preferred Stock, 3,002,648 shares are designated as Series B
Preferred Stock and 15,000 shares are designated as Series C Preferred Stock.

        3. There were 18,851,000 shares of Common Stock and no shares of
Preferred Stock outstanding as of the record date (the "Record Date") of the
shareholders' meeting at which the Agreement and Plan of Merger attached hereto
(the "Merger Agreement") was approved. All shares of Common Stock outstanding
were entitled to vote on the merger.

        4. The principal terms of the Merger Agreement were approved by the
Board of Directors and by the vote of a number of shares of each class of stock
which equaled or exceeded the vote required.

        5. The percentage vote required was more than 50% of the votes entitled
to be cast by holders of Common Stock outstanding as of the Record Date, voting
as a single class.

        6. Barry M. Sherman, M.D. and David V. Smith further declare under
penalty of perjury under the laws of the State of California that each has read
the foregoing certificate and knows the contents thereof and that the same is
true of their own knowledge.

        Executed in Redwood City, California on June 30, 1998.



                                      /s/ BARRY M. SHERMAN
                                      -----------------------------------------
                                      Barry M. Sherman, M.D., President


                                      /s/ DAVID V. SMITH
                                      -----------------------------------------
                                      David V. Smith, Chief Financial Officer


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                                  ANERGEN, INC.
                             (Surviving Corporation)

                              OFFICERS' CERTIFICATE


Barry M. Sherman, M.D. and David V. Smith certify that:

        1. They are the President and Chief Financial Officer, respectively, of
Anergen, Inc., a corporation organized under the laws of the State of Delaware.

        2. The corporation has authorized two classes of stock, designated
"Common Stock" and "Preferred Stock". There are authorized 60,000,000 shares of
Common Stock and 10,000,000 shares of Preferred Stock. The Preferred Stock is
undesignated as to series, rights, preferences or restrictions.

        3. There were 1,000 shares of Common Stock outstanding and entitled to
vote on the Agreement and Plan of Merger attached hereto (the "Merger
Agreement"). There were no shares of Preferred Stock outstanding.

        4. The principal terms of the Merger Agreement were approved by the
Board of Directors and by the vote of a number of shares of each class of stock
which equaled or exceeded the vote required.

        5. The percentage vote required was more than 50% of the votes entitled
to be cast by holders of outstanding shares of Common Stock.

        6. Barry M. Sherman, M.D. and David V. Smith further declare under
penalty of perjury under the laws of the State of Delaware that each has read
the foregoing certificate and knows the contents thereof and that the same is
true of their own knowledge.

        Executed in Redwood City, California on June 30, 1998.


                                      /s/ BARRY M. SHERMAN
                                      -----------------------------------------
                                      Barry M. Sherman, M.D., President


                                      /s/ DAVID V. SMITH
                                      -----------------------------------------
                                      David V. Smith, Chief Financial Officer


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                                  ANERGEN, INC.
                             (Surviving Corporation)

                              OFFICERS' CERTIFICATE


Barry M. Sherman, M.D. and David V. Smith certify that:

        1. They are the President and Chief Financial Officer, respectively, of
Anergen, Inc., a corporation organized under the laws of the State of Delaware.

        2. The corporation has authorized two classes of stock, designated
"Common Stock" and "Preferred Stock". There are authorized 60,000,000 shares of
Common Stock and 10,000,000 shares of Preferred Stock. The Preferred Stock is
undesignated as to series, rights, preferences or restrictions.

        3. There were 100 shares of Common Stock outstanding and entitled to
vote on the Agreement and Plan of Merger attached hereto (the "Merger
Agreement"). There were no shares of Preferred Stock outstanding.

        4. The principal terms of the Merger Agreement were approved by the
Board of Directors and by the vote of a number of shares of each class of stock
which equaled or exceeded the vote required.

        5. The percentage vote required was more than 50% of the votes entitled
to be cast by holders of outstanding shares of Common Stock.

        6. Barry M. Sherman, M.D. and David V. Smith further declare under
penalty of perjury under the laws of the State of California that each has read
the foregoing certificate and knows the contents thereof and that the same is
true of their own knowledge.

        Executed in Redwood City, California on June 30, 1998.



                                      /s/ BARRY M. SHERMAN
                                      -----------------------------------------
                                      Barry M. Sherman, M.D., President


                                      /s/ DAVID V. SMITH
                                      -----------------------------------------
                                      David V. Smith, Chief Financial Officer