VICAL INCORPORATED

                            [2,500,000 SHARES (*)]

                                 COMMON STOCK

                            UNDERWRITING AGREEMENT

                                                  ....................., 2000

Goldman, Sachs & Co.,
BancBoston Robertson Stephens
SG Cowen Securities Corporation
First Union Securities, Inc.
    As representatives of the several Underwriters
     named in Schedule I hereto,
c/o Goldman, Sachs & Co.
85 Broad Street,
New York, New York 10004

Ladies and Gentlemen:

     Vical Incorporated, a Delaware corporation (the "Company"), proposes,
subject to the terms and conditions stated herein, to issue and sell to the
Underwriters named in Schedule I hereto (the "Underwriters") an aggregate of
[2,500,000] shares and, at the election of the Underwriters, up to [375,000]
additional shares of Common Stock, $.01 par value ("Stock"), of the Company.
The aggregate of [2,500,000] shares to be sold by the Company is herein called
the "Shares" and the aggregate of [375,000] additional shares to be sold by the
Company is herein called the "Optional Shares."  The Firm Shares and the
Optional Shares that the Underwriters elect to purchase pursuant to Section 2
hereof are herein collectively called the "Shares."

     1.   (a)  The Company represents and warrants to, and agrees with, each of
the Underwriters that:

               (i)     A registration statement on Form S-3 (File No. 333-_____)
(the "Initial Registration Statement") in respect of the Shares has been filed
with the Securities and Exchange Commission (the "Commission"); the Initial
Registration Statement and any post-effective amendment thereto, each in the
form heretofore delivered to you, and, excluding exhibits thereto but including
all documents incorporated by reference in the prospectus contained therein, to
you for each of the other Underwriters, have been declared effective by the
Commission in such form; other than a registration statement, if any, increasing
the size of the offering (a "Rule 462(b) Registration Statement"), filed
pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the
"Act"), which became effective upon filing, no other document with respect to
the Initial Registration Statement or document

- ------------------------
* Plus an option to purchase from the Company up to 375,000 additional shares
  to cover over-allotments.


                                     1.




incorporated by reference therein has heretofore been filed with the
Commission; and no stop order suspending the effectiveness of the Initial
Registration Statement, any post-effective amendment thereto or the Rule
462(b) Registration Statement, if any, has been issued and no proceeding for
that purpose has been initiated or threatened by the Commission (any
preliminary prospectus included in the Initial Registration Statement or
filed with the Commission pursuant to Rule 424(a) of the rules and
regulations of the Commission under the Act is hereinafter called  a
"Preliminary Prospectus";  the various parts of the Initial Registration
Statement and the Rule 462(b) Registration Statement, if any, including all
exhibits thereto and including (i) the information contained in the form of
final prospectus filed with the Commission pursuant to Rule 424(b) under the
Act in accordance with Section 5(a) hereof and deemed by virtue of Rule 430A
under the Act to be part of the Initial Registration Statement at the time it
was declared effective and (ii) the documents incorporated by reference in
the prospectus contained in the Initial Registration Statement at the time
such part of the Initial Registration Statement became effective, each as
amended at the time such part of the Initial Registration Statement became
effective or such part of the Rule 462(b) Registration Statement, if any,
became or hereafter becomes effective, are hereinafter collectively called
the "Registration Statement"; such final prospectus, in the form first filed
pursuant to Rule 424(b) under the Act, is hereinafter called the
"Prospectus"; and any reference herein to any Preliminary Prospectus or the
Prospectus shall be deemed to refer to and include the documents incorporated
by reference therein pursuant to Item 12 of Form S-3 under the Act, as of the
date of such Preliminary Prospectus or Prospectus, as the case may be; any
reference to any amendment or supplement to any Preliminary Prospectus or the
Prospectus shall be deemed to refer to and include any documents filed after
the date of such Preliminary Prospectus or Prospectus, as the case may be,
under the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
and incorporated by reference in such Preliminary Prospectus or Prospectus,
as the case may be; and any reference to any amendment to the Registration
Statement shall be deemed to refer to and include any annual report of the
Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act after
the effective date of the Initial Registration Statement that is incorporated
by reference in the Registration Statement;

               (ii)    No order preventing or suspending the use of any
Preliminary Prospectus has been issued by the Commission, and each
Preliminary Prospectus, at the time of filing thereof, conformed in all
material respects to the requirements of the Act and the rules and
regulations of the Commission thereunder, and did not contain an untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading; PROVIDED,
HOWEVER, that this representation and warranty shall not apply to any
statements or omissions made in reliance upon and in conformity with
information furnished in writing to the Company by an Underwriter through
Goldman, Sachs & Co. expressly for use therein in the preparation of the
answers therein to Item 7 of Form S-3;

               (iii)   The documents incorporated by reference in the
Prospectus, when they became effective or were filed with the Commission, as the
case may be, conformed in all material respects to the requirements of the Act
or the Exchange Act, as applicable, and the rules and regulations of the
Commission thereunder, and none of such documents contained an untrue statement
of a material fact or omitted to state a material fact required to be stated
therein or necessary to make

                                     2.



the statements therein not misleading; and any further documents so filed and
incorporated by reference in the Prospectus or any further amendment or
supplement thereto, when such documents become effective or are filed with
the Commission, as the case may be, will conform in all material respects to
the requirements of the Act or the Exchange Act, as applicable, and the rules
and regulations of the Commission thereunder and will not contain an untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein not misleading;
provided, however, that this representation and warranty shall not apply to
any statements or omissions made in reliance upon and in conformity with
information furnished in writing to the Company by an Underwriter through
Goldman, Sachs & Co. expressly for use therein;

               (iv)    The Registration Statement conforms, and the Prospectus
and any further amendments or supplements to the Registration Statement or the
Prospectus will conform, in all material respects to the requirements of the Act
and the rules and regulations of the Commission thereunder and do not and will
not, as of the applicable effective date as to the Registration Statement and
any amendment thereto and as of the applicable filing date as to the Prospectus
and any amendment or supplement thereto, contain an untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein not misleading; PROVIDED, HOWEVER, that
this representation and warranty shall not apply to any statements or omissions
made in reliance upon and in conformity with information furnished in writing to
the Company by an Underwriter through Goldman, Sachs & Co. expressly for use
therein in the preparation of the answers therein to Item 7 of Form S-3;

               (v)     Neither the Company nor any of its subsidiaries has
sustained since the date of the latest audited financial statements included or
incorporated by reference in the Prospectus any material loss or interference
with its business from fire, explosion, flood or other calamity, whether or not
covered by insurance, or from any labor dispute or court or governmental action,
order or decree, otherwise than as set forth or contemplated in the Prospectus;
and, since the respective dates as of which information is given in the
Registration Statement and the Prospectus, there has not been any change in the
capital stock or long-term debt of the Company or any of its subsidiaries or any
material adverse change, or any development involving a prospective material
adverse change, in or affecting the general affairs, management, financial
position, stockholders' equity or results of operations of the Company and its
subsidiaries, otherwise than as set forth or contemplated in the Prospectus;

               (vi)    The Company and its subsidiaries have good and
marketable title in fee simple to all real property and good and marketable
title to all personal property owned by them, in each case free and clear of all
liens, encumbrances and defects except such as are described in the Prospectus
or such as do not materially affect the value of such property and do not
interfere with the use made and proposed to be made of such property by the
Company and its subsidiaries; and any real property and buildings held under
lease by the Company and its subsidiaries are held by them under valid,
subsisting and enforceable leases with such exceptions as are not material and
do not interfere with the use made and proposed to be made of such property and
buildings by the Company and its subsidiaries;


                                     3.



               (vii)   The Company has been duly incorporated and is validly
existing as a corporation in good standing under the laws of the State of
Delaware, with power and authority (corporate and other) to own its properties
and conduct its business as described in the Prospectus, and has been duly
qualified as a foreign corporation for the transaction of business and is in
good standing under the laws of each other jurisdiction in which it owns or
leases properties or conducts any business so as to require such qualification,
or is subject to no material liability or disability by reason of the failure to
be so qualified in any such jurisdiction; and each subsidiary of the Company has
been duly incorporated and is validly existing as a corporation in good standing
under the laws of its jurisdiction of incorporation;

               (viii)  The Company has an authorized capitalization as set
forth in the Prospectus, and all of the issued shares of capital stock of the
Company have been duly and validly authorized and issued, are fully paid and
non-assessable and conform to the description of the Stock contained in the
Prospectus; and all of the issued shares of capital stock of each subsidiary of
the Company have been duly and validly authorized and issued, are fully paid and
non-assessable and (except for directors' qualifying shares) are owned directly
or indirectly by the Company, free and clear of all liens, encumbrances,
equities or claims;

               (ix)    The unissued Shares to be issued and sold by the Company
to the Underwriters hereunder have been duly and validly authorized and, when
issued and delivered against payment therefor as provided herein, will be duly
and validly issued and fully paid and non-assessable and will conform to the
description of the Stock contained in the Prospectus;

               (x)     The issue and sale of the Shares to be sold by the
Company and the compliance by the Company with all of the provisions of this
Agreement and the consummation of the transactions herein contemplated will not
conflict with or result in a breach or violation of any of the terms or
provisions of, or constitute a default under, any indenture, mortgage, deed of
trust, loan agreement or other agreement or instrument to which the Company or
any of its subsidiaries is a party or by which the Company or any of its
subsidiaries is bound or to which any of the property or assets of the Company
or any of its subsidiaries is subject, nor will such action result in any
violation of the provisions of the Certificate of Incorporation or By-laws of
the Company or any statute or any order, rule or regulation of any court or
governmental agency or body having jurisdiction over the Company or any of its
subsidiaries or any of their properties; and no consent, approval,
authorization, order, registration or qualification of or with any such court or
governmental agency or body is required for the issue and sale of the Shares or
the consummation by the Company of the transactions contemplated by this
Agreement, except the registration under the Act of the Shares and such
consents, approvals, authorizations, registrations or qualifications as may be
required under state securities or Blue Sky laws in connection with the purchase
and distribution of the Shares by the Underwriters;

               (xi)    There are no rights of any person, corporation,
partnership or other entity not effectively satisfied or waived, to require
registration of any shares of Common Stock or any other securities of the
Company in connection with the filing of the Registration Statement;

               (xii)   Neither the Company nor any of its subsidiaries is in
violation of its Certificate of Incorporation or By-laws or in default in the
performance or observance of any material


                                     4.



obligation, agreement, covenant or condition contained in any indenture,
mortgage, deed of trust, loan agreement, lease or other agreement or
instrument to which it is a party or by which it or any of its properties may
be bound;

               (xiii)  The statements set forth in the Prospectus under the
caption "Description of Capital Stock," insofar as they purport to constitute a
summary of the terms of the Stock and under the caption "Underwriting," insofar
as they purport to describe the provisions of the laws and documents referred to
therein, are accurate, complete and fair;

               (xiv)   Other than as set forth in the Prospectus, there are no
legal or governmental proceedings pending to which the Company or any of its
subsidiaries is a party or of which any property of the Company or any of its
subsidiaries is the subject which, if determined adversely to the Company or any
of its subsidiaries, would individually or in the aggregate have a material
adverse effect on the current or future consolidated financial position,
stockholders' equity or results of operations of the Company and its
subsidiaries; and, to the best of the Company's knowledge, no such proceedings
are threatened or contemplated by governmental authorities or threatened by
others;

               (xv)    The Company is not and, after giving effect to the
offering and sale of the Shares, will not be an "investment company", as such
term is defined in the Investment Company Act of 1940, as amended (the
"Investment Company Act");

               (xvi)   Neither the Company nor any of its affiliates does
business with the government of Cuba or with any person or affiliate located in
Cuba within the meaning of Section 517.075, Florida Statutes;

               (xvii)  The Company owns or possesses, or believes it can
acquire on reasonable terms, all material patents (or foreign equivalents),
trademarks, licenses, copyrights and proprietary or other confidential
information currently employed by it in connection with its business except such
as the failure to so own, possess or acquire would not have a material adverse
effect on the Company and except that rights to use particular genes may or may
not be available.  In connection with the filing of its patent applications, the
Company has either conducted reasonable investigations of the published
literature and patent references relating to the inventions claimed in such
applications or is relying on searches conducted or to be conducted by
governmental authorities in connection with examination of its patent
applications.  Except as to the use of particular genes for particular
applications, which the Company intends to investigate on a case-by-case basis,
there are no enforceable United States or foreign patents known to the Company
which the Company believes to be infringed by its present activities or which
would preclude the pursuit of its business as described in the Prospectus.
Except for matters already resolved and matters the Company has determined are
without merit and which would not have a material adverse effect on the
Company's business, the Company has not received any notice of infringement of
or conflict with asserted rights of any third party with respect to any of the
foregoing.


                                     5.



               (xviii) Arthur Andersen LLP, who have certified certain
financial statements of the Company and its subsidiaries, are independent public
accountants as required by the Act and the rules and regulations of the
Commission thereunder; and

               (xix)   The Company has reviewed its operations and that of its
subsidiaries and any third parties with which the Company or any of its
subsidiaries has a material relationship to evaluate the extent to which the
business or operations of the Company or any of its subsidiaries will be
affected by the Year 2000 Problem.  As a result of such review, the Company has
no reason to believe, and does not believe, that the Year 2000 Problem will have
a material adverse effect on the general affairs, management, the current or
future consolidated financial position, business prospects, stockholders' equity
or results of operations of the Company and its subsidiaries or result in any
material loss or interference with the Company's business or operations.  The
"Year 2000 Problem" as used herein means any significant risk that computer
hardware or software used in the receipt, transmission, processing,
manipulation, storage, retrieval, retransmission or other utilization of data or
in the operation of mechanical or electrical systems of any kind will not, in
the case of dates or time periods occurring after December 31, 1999, function at
least as effectively as in the case of dates or time periods occurring prior to
January 1, 2000.

     2.   Subject to the terms and conditions herein set forth, (a) the Company
agrees, to sell to each of the Underwriters, and each of the Underwriters
agrees, severally and not jointly, to purchase from the Company, at a purchase
price per share of $.............., the number of Firm Shares (to be adjusted by
you so as to eliminate fractional shares) determined by multiplying the
aggregate number of Firm Shares to be sold by the Company by a fraction, the
numerator of which is the aggregate number of Firm Shares to be purchased by
such Underwriter as set forth opposite the name of such Underwriter in Schedule
I hereto and the denominator of which is the aggregate number of Firm Shares to
be purchased by all of the Underwriters from the Company hereunder and (b) in
the event and to the extent that the Underwriters shall exercise the election to
purchase Optional Shares as provided below, the Company agrees to sell to each
of the Underwriters, and each of the Underwriters agrees, severally and not
jointly, to purchase from the Company, at the purchase price per share set forth
in clause (a) of this Section 2, that portion of the number of Optional Shares
as to which such election shall have been exercised (to be adjusted by you so as
to eliminate fractional shares) determined by multiplying such number of
Optional Shares by a fraction the numerator of which is the maximum number of
Optional Shares which such Underwriter is entitled to purchase as set forth
opposite the name of such Underwriter in Schedule I hereto and the denominator
of which is the maximum number of Optional Shares that all of the Underwriters
are entitled to purchase hereunder.

     The Company hereby grants to the Underwriters the right to purchase at
their election up to [375,000] Optional Shares, at the purchase price per share
set forth in the paragraph above, for the sole purpose of covering over
allotments in the sale of the Firm Shares.  Any such election to purchase
Optional Shares may be exercised only by written notice from you to the Company,
given within a period of 30 calendar days after the date of this Agreement and
setting forth the aggregate number of Optional Shares to be purchased and the
date on which such Optional Shares are to be delivered, as determined by you but
in no event earlier than the First Time of Delivery (as defined in Section 4


                                      6.



hereof) or, unless you and the Company otherwise agree in writing, earlier than
two or later than ten business days after the date of such notice.

     As compensation to the Underwriters for their commitments hereunder, the
Company at each Time of Delivery (as defined in Section 4 hereof) will pay to
Goldman, Sachs & Co., for the accounts of the several Underwriters, an amount
equal to $. . . . . . . . per share for the Shares to be delivered by the
Company  hereunder at such Time of Delivery.

     3.   Upon the authorization by you of the release of the Firm Shares, the
several Underwriters propose to offer the Firm Shares for sale upon the terms
and conditions set forth in the Prospectus.

     4.   (a)  The Shares to be purchased by each Underwriter hereunder, in
definitive form, and in such authorized denominations and registered in such
names as Goldman, Sachs & Co. may request upon at least forty-eight hours' prior
notice to the Company shall be delivered by or on behalf of the Company to
Goldman, Sachs & Co., through the facilities of the Depository Trust Company
("DTC"), for the account of such Underwriter, against payment by or on behalf of
such Underwriter of the purchase price therefor by wire transfer of Federal
(same-day) funds to the account specified by the Company to Goldman, Sachs & Co.
at least forty-eight hours in advance.  The Company will cause the certificates
representing the Shares to be made available for checking and packaging at least
twenty-four hours prior to the Time of Delivery (as defined below) with respect
thereto at the office of DTC or its designated custodian or Goldman, Sachs &
Co., 85 Broad Street, New York, New York 10004 (the "Designated Office").  The
time and date of such delivery and payment shall be, with respect to the Firm
Shares, 9:30 a.m., New York time, on ............., 2000 or such other time and
date as Goldman, Sachs & Co. and the Company may agree upon in writing, and,
with respect to the Optional Shares, 9:30 a.m., New York time, on the date
specified by Goldman, Sachs & Co. in the written notice given by Goldman, Sachs
& Co. of the Underwriters' election to purchase such Optional Shares, or such
other time and date as Goldman, Sachs & Co. and the Company and may agree upon
in writing.  Such time and date for delivery of the Firm Shares is herein called
the "First Time of Delivery," such time and date for delivery of the Optional
Shares, if not the First Time of Delivery, is herein called the "Second Time of
Delivery," and each such time and date for delivery is herein called a "Time of
Delivery."

     At each Time of Delivery, the Company will pay, or cause to be paid, the
commission payable at such Time of Delivery to the Underwriters under Section 2
hereof by wire transfer of Federal (same-day) funds to the account specified by
Goldman, Sachs & Co.

          (b)  The documents to be delivered at each Time of Delivery by or on
behalf of the parties hereto pursuant to Section 7 hereof, including the cross
receipt for the Shares and any additional documents requested by the
Underwriters pursuant to Section 7[(k)] hereof, will be delivered at the offices
of [Pillsbury, Madison & Sutro LLP] [101 West Broadway, Suite 1800, San Diego,
California  92101] (the "Closing Location"), and the Shares will be delivered at
the Designated Office, all at such Time of Delivery.  A meeting will be held at
the Closing Location at .......p.m., New York City time, on the New York
Business Day next preceding such Time of Delivery, at which meeting the final
drafts of the documents to be delivered pursuant to the preceding sentence


                                     7.



will be available for review by the parties hereto.  For the purposes of this
Section 4, "New York Business Day" shall mean each Monday, Tuesday,
Wednesday, Thursday and Friday which is not a day on which banking
institutions in New York are generally authorized or obligated by law or
executive order to close.

     5.   The Company agrees with each of the Underwriters:

          (a)  To prepare the Prospectus in a form approved by you and to file
such Prospectus pursuant to Rule 424(b) under the Act not later than the
Commission's close of business on the second business day following the
execution and delivery of this Agreement, or, if applicable, such earlier time
as may be required by Rule 430A(a)(3) under the Act; to make no further
amendment or any supplement to the Registration Statement or Prospectus prior to
the last Time of Delivery which shall be disapproved by you promptly after
reasonable notice thereof; to advise you, promptly after it receives notice
thereof, of the time when any amendment to the Registration Statement has been
filed or becomes effective or any supplement to the Prospectus or any amended
Prospectus has been filed and to furnish you with copies thereof; to file
promptly all reports and any definitive proxy or information statements required
to be filed by the Company with the Commission pursuant to Section 13(a), 13(c),
14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for
so long as the delivery of a prospectus is required in connection with the
offering or sale of the Shares; to advise you, promptly after it receives notice
thereof, of the issuance by the Commission of any stop order or of any order
preventing or suspending the use of any Preliminary Prospectus or prospectus, of
the suspension of the qualification of the Shares for offering or sale in any
jurisdiction, of the initiation or threatening of any proceeding for any such
purpose, or of any request by the Commission for the amending or supplementing
of the Registration Statement or Prospectus or for additional information; and,
in the event of the issuance of any stop order or of any order preventing or
suspending the use of any Preliminary Prospectus or prospectus or suspending any
such qualification, promptly to use its best efforts to obtain the withdrawal of
such order;

          (b)  Promptly from time to time to take such action as you may
reasonably request to qualify the Shares for offering and sale under the
securities laws of such jurisdictions as you may request and to comply with such
laws so as to permit the continuance of sales and dealings therein in such
jurisdictions for as long as may be necessary to complete the distribution of
the Shares, provided that in connection therewith the Company shall not be
required to qualify as a foreign corporation or to file a general consent to
service of process in any jurisdiction;

          (c)  Prior to 10:00 A.M., New York City time, on the New York Business
Day next succeeding the date of this Agreement and from time to time, to furnish
the Underwriters with copies of the Prospectus in New York City in such
quantities as you may reasonably request, and, if the delivery of a prospectus
is required at any time prior to the expiration of nine months after the time of
issue of the Prospectus in connection with the offering or sale of the Shares
and if at such time any events shall have occurred as a result of which the
Prospectus as then amended or supplemented would include an untrue statement of
a material fact or omit to state any material fact necessary in order to make
the statements therein, in the light of the circumstances under which they were
made when such Prospectus is delivered, not misleading, or, if for any other
reason it shall be necessary during such


                                      8.



period to amend or supplement the Prospectus or to file under the Exchange
Act any document incorporated by reference in the Prospectus in order to
comply with the Act or the Exchange Act, to notify you and upon your request
to file such document and to prepare and furnish without charge to each
Underwriter and to any dealer in securities as many copies as you may from
time to time reasonably request of an amended Prospectus or a supplement to
the Prospectus which will correct such statement or omission or effect such
compliance, and in case any Underwriter is required to deliver a prospectus
in connection with sales of any of the Shares at any time nine months or more
after the time of issue of the Prospectus, upon your request but at the
expense of such Underwriter, to prepare and deliver to such Underwriter as
many copies as you may request of an amended or supplemented Prospectus
complying with Section 10(a)(3) of the Act;

          (d)  To make generally available to its securityholders as soon as
practicable, but in any event not later than eighteen months after the effective
date of the Registration Statement (as defined in Rule 158(c) under the Act), an
earnings statement of the Company and its subsidiaries (which need not be
audited) complying with Section 11(a) of the Act and the rules and regulations
of the Commission thereunder (including, at the option of the Company, Rule
158);

          (e)  During the period beginning from the date hereof and continuing
to and including the date 90 days after the date of the Prospectus, not to
offer, sell, contract to sell or otherwise dispose of, except as provided
hereunder, any securities of the Company that are substantially similar to the
Shares, including but not limited to any securities that are convertible into or
exchangeable for, or that represent the right to receive, Stock or any such
substantially similar securities (other than pursuant to employee stock option
plans existing on, or upon the conversion or exchange of convertible or
exchangeable securities outstanding as of, the date of this Agreement), without
your prior written consent;

          (f)  To furnish to its stockholders as soon as practicable after the
end of each fiscal year an annual report (including a balance sheet and
statements of income, stockholders' equity and cash flows of the Company and its
consolidated subsidiaries certified by independent public accountants) and, as
soon as practicable after the end of each of the first three quarters of each
fiscal year (beginning with the fiscal quarter ending after the effective date
of the Registration Statement), to make available to its stockholders
consolidated summary financial information of the Company and its subsidiaries
for such quarter in reasonable detail;

          (g)  During a period of five years from the effective date of the
Registration Statement, to furnish to you copies of all reports or other
communications (financial or other) furnished to stockholders, and to deliver to
you (i) as soon as they are available, copies of any reports and financial
statements furnished to or filed with the Commission or any national securities
exchange on which any class of securities of the Company is listed; and (ii)
such additional information concerning the business and financial condition of
the Company as you may from time to time reasonably request (such financial
statements to be on a consolidated basis to the extent the accounts of the
Company and its subsidiaries are consolidated in reports furnished to its
stockholders generally or to the Commission);


                                      9.



          (h)  To use the net proceeds received by it from the sale of the
Shares pursuant to this Agreement in the manner specified in the Prospectus
under the caption "Use of Proceeds";

          (i)  To list for quotation the Shares on the National Association of
Securities Dealers Automated Quotations National Market System ("NASDAQ"); and

          (j)  If the Company elects to rely upon Rule 462(b), the Company shall
file a Rule 462(b) Registration Statement with the Commission in compliance with
Rule 462(b) by 10:00 P.M., Washington, D.C. time, on the date of this Agreement,
and the Company shall at the time of filing either pay to the Commission the
filing fee for the Rule 462(b) Registration Statement or give irrevocable
instructions for the payment of such fee pursuant to Rule 111(b) under the Act.

     6.   The Company covenants and agrees with the several Underwriters that
(a) the Company will pay or cause to be paid the following: (i) the fees,
disbursements and expenses of the Company's counsel and accountants in
connection with the registration of the Shares under the Act and all other
expenses in connection with the preparation, printing and filing of the
Registration Statement, any Preliminary Prospectus and the Prospectus and
amendments and supplements thereto and the mailing and delivering of copies
thereof to the Underwriters and dealers; (ii) the cost of printing or producing
any Agreement among Underwriters, this Agreement, the Blue Sky Memorandum,
closing documents (including any compilations thereof) and any other documents
in connection with the offering, purchase, sale and delivery of the Shares;
(iii) all expenses in connection with the qualification of the Shares for
offering and sale under state securities laws as provided in Section 5(b)
hereof, including the fees and disbursements of counsel for the Underwriters in
connection with such qualification and in connection with the Blue Sky survey
(iv) all fees and expenses in connection with listing the Shares on the NASDAQ;
(b) the filing fees incident to, and the fees and disbursements of counsel for
the Underwriters in connection with, securing any required review by the
National Association of Securities Dealers, Inc. of the terms of the sale of the
Shares; and (c) the Company will pay or cause to be paid: (i) the cost of
preparing stock certificates; (ii) the cost and charges of any transfer agent or
registrar and (iii) all other costs and expenses incident to the performance of
its obligations hereunder which are not otherwise specifically provided for in
this Section.  It is understood, however, that the Company shall bear the cost
of any other matters not directly relating to the sale and purchase of the
Shares pursuant to this Agreement, and that, except as provided in this Section,
and Sections 8 and 11 hereof, the Underwriters will pay all of their own costs
and expenses, including the fees of their counsel, stock transfer taxes on
resale of any of the Shares by them, and any advertising expenses connected with
any offers they may make.

     7.   The obligations of the Underwriters hereunder, as to the Shares to be
delivered at each Time of Delivery, shall be subject, in their discretion, to
the condition that all representations and warranties and other statements of
the Company herein are, at and as of such Time of Delivery, true and correct,
the condition that the Company shall have performed all of its obligations
hereunder theretofore to be performed, and the following additional conditions:

          (a)  The Prospectus shall have been filed with the Commission pursuant
to Rule 424(b) within the applicable time period prescribed for such filing by
the rules and regulations under the Act and in accordance with Section 5(a)
hereof; if the Company has elected to rely upon Rule


                                     10.



462(b), the Rule 462(b) Registration Statement shall have become effective by
10:00 P.M., Washington, D.C. time, on the date of this Agreement; no stop
order suspending the effectiveness of the Registration Statement or any part
thereof shall have been issued and no proceeding for that purpose shall have
been initiated or threatened by the Commission; and all requests for
additional information on the part of the Commission shall have been complied
with to your reasonable satisfaction;

          (b)  Cooley Godward LLP, counsel for the Underwriters, shall have
furnished to you such written opinion or opinions (a draft of each such opinion
is attached as Annex II(a) hereto), dated such Time of Delivery, with respect to
the matters covered in paragraphs (i), (ii), (vii), (xi), [(xiii) and (xiv)] of
subsection (c) below as well as such other related matters as you may reasonably
request, and such counsel shall have received such papers and information as
they may reasonably request to enable them to pass upon such matters;

          (c)  Pillsbury Madison & Sutro LLP, counsel for the Company, shall
have furnished to you their written opinion (a draft of such opinion is attached
as Annex II(b) hereto), dated such Time of Delivery, in form and substance
satisfactory to you, to the effect that:

               (i)     The Company has been duly incorporated and is validly
existing as a corporation in good standing under the laws of the State of
Delaware, with power and authority (corporate and other) to own its properties
and conduct its business as described in the Prospectus;

               (ii)    The Company has an authorized capitalization as set
forth in the Prospectus, and all of the issued shares of capital stock of the
Company (including the Shares being delivered at such Time of Delivery) have
been duly and validly authorized and issued and are fully paid and
non-assessable; and the Shares conform to the description of the Stock contained
in the Prospectus;

               (iii)   The Company has been duly qualified as a foreign
corporation for the transaction of business and is in good standing under the
laws of each other jurisdiction in which it owns or leases properties or
conducts any business so as to require such qualification, or is subject to no
material liability or disability by reason of failure to be so qualified in any
such jurisdiction (such counsel being entitled to rely in respect of the opinion
in this clause upon opinions of local counsel and in respect of matters of fact
upon certificates of officers of the Company, provided that such counsel shall
state that they believe that both you and they are justified in relying upon
such opinions and certificates);

               (iv)    [Each subsidiary of the Company has been duly
incorporated and is validly existing as a corporation in good standing under the
laws of its jurisdiction of incorporation; and all of the issued shares of
capital stock of each such subsidiary have been duly and validly authorized and
issued, are fully paid and non-assessable, and (except for directors' qualifying
shares) are owned directly or indirectly by the Company, free and clear of all
liens, encumbrances, equities or claims (such counsel being entitled to rely in
respect of the opinion in this clause upon opinions of local counsel and in
respect of matters of fact upon certificates of officers of the Company or its


                                     11.



subsidiaries, provided that such counsel shall state that they believe that both
you and they are justified in relying upon such opinions and certificates);]

               (v)     [The Company and its subsidiaries have good and
marketable title in fee simple to all real property owned by them, in each case
free and clear of all liens, encumbrances and defects except such as are
described in the Prospectus or such as do not materially affect the value of
such property and do not interfere with the use made and proposed to be made of
such property by the Company and its subsidiaries; and any real property and
buildings held under lease by the Company and its subsidiaries are held by them
under valid, subsisting and enforceable leases with such exceptions as are not
material and do not interfere with the use made and proposed to be made of such
property and buildings by the Company and its subsidiaries (in giving the
opinion in this clause, such counsel may state that no examination of record
titles for the purpose of such opinion has been made, and that they are relying
upon a general review of the titles of the Company and its subsidiaries, upon
opinions of local counsel and abstracts, reports and policies of title companies
rendered or issued at or subsequent to the time of acquisition of such property
by the Company or its subsidiaries, upon opinions of counsel to the lessors of
such property and, in respect of matters of fact, upon certificates of officers
of the Company or its subsidiaries, provided that such counsel shall state that
they believe that both you and they are justified in relying upon such opinions,
abstracts, reports, policies and certificates);]

               (vi)    To the best of such counsel's knowledge and other than
as set forth in the Prospectus, there are no legal or governmental proceedings
pending to which the Company or any of its subsidiaries is a party or of which
any property of the Company or any of its subsidiaries is the subject which, if
determined adversely to the Company or any of its subsidiaries, would
individually or in the aggregate have a material adverse effect on the current
or future consolidated financial position stockholders' equity or results of
operations of the Company and its subsidiaries; and, to the best of such
counsel's knowledge, no such proceedings are threatened or contemplated by
governmental authorities or threatened by others;

               (vii)   This Agreement has been duly authorized, executed and
delivered by the Company;

               (viii)  The issue and sale of the Shares being delivered at such
Time of Delivery to be sold by the Company and the compliance by the Company
with all of the provisions of this Agreement and the consummation of the
transactions herein contemplated will not conflict with or result in a breach or
violation of any of the terms or provisions of, or constitute a default under,
any indenture, mortgage, deed of trust, loan agreement or other agreement or
instrument known to such counsel to which the Company or any of its subsidiaries
is a party or by which the Company or any of its subsidiaries is bound or to
which any of the property or assets of the Company or any of its subsidiaries is
subject, nor will such action result in any violation of the provisions of the
Certificate of Incorporation or By-laws of the Company or any statute or any
order, rule or regulation known to such counsel of any court or governmental
agency or body having jurisdiction over the Company or any of its subsidiaries
or any of their properties;


                                      12.



               (ix)    No consent, approval, authorization, order, registration
or qualification of or with any such court or governmental agency or body is
required for the issue and sale of the Shares or the consummation by the Company
of the transactions contemplated by this Agreement, except the registration
under the Act of the Shares, and such consents, approvals, authorizations,
registrations or qualifications as may be required under state securities or
Blue Sky laws in connection with the purchase and distribution of the Shares by
the Underwriters;

               (x)     Neither the Company nor any of its subsidiaries is in
violation of its Certificate of Incorporation or By-laws;

               (xi)    The statements set forth in the Prospectus under the
caption "Description of Capital Stock," insofar as they purport to constitute a
summary of the terms of the Stock and under the caption "Underwriting," insofar
as they purport to describe the provisions of the laws and documents referred to
therein, are accurate, complete and fair;

               (xii)   The Company is not an "investment company", as such term
is defined in the Investment Company Act;

               (xiii)  The documents incorporated by reference in the
Prospectus or any further amendment or supplement thereto made by the Company
prior to such Time of Delivery (other than the financial statements and related
schedules therein, as to which such counsel need express no opinion), when they
became effective or were filed with the Commission, as the case may be, complied
as to form in all material respects with the requirements of the Act or the
Exchange Act, as applicable, and the rules and regulations of the Commission
thereunder; and they have no reason to believe that any of such documents, when
such documents became effective or were so filed, as the case may be, contained,
in the case of a registration statement which became effective under the Act, an
untrue statement of a material fact, or omitted to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading, or, in the case of other documents which were filed under the
Exchange Act with the Commission, an untrue statement of a material fact or
omitted to state a material fact necessary in order to make the statements
therein, in the light of the circumstances under which they were made when such
documents were so filed, not misleading; and

               (xiv)   The Registration Statement and the Prospectus and any
further amendments and supplements thereto made by the Company prior to such
Time of Delivery (other than the financial statements and related schedules
therein, as to which such counsel need express no opinion) comply as to form
in all material respects with the requirements of the Act and the rules and
regulations thereunder; although they do not assume any responsibility for
the accuracy, completeness or fairness of the statements contained in the
Registration Statement or the Prospectus, except for those referred to in the
opinion in subsection (xi) of this Section 7(c), they have no reason to
believe that, as of its effective date, the Registration Statement or any
further amendment thereto made by the Company prior to such Time of Delivery
(other than the financial statements and related schedules therein, as to
which such counsel need express no opinion) contained an untrue statement of
a material fact or omitted to state a material fact required to be stated
therein or necessary to make the statements therein not misleading or that,
as of its date, the Prospectus or any further amendment or supplement thereto
made by the Company prior to such Time of Delivery (other than the financial
statements and

                                    13.



related schedules therein, as to which such counsel need express no opinion)
contained an untrue statement of a material fact or omitted to state a
material fact necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading or that, as of such
Time of Delivery, either the Registration Statement or the Prospectus or any
further amendment or supplement thereto made by the Company prior to such
Time of Delivery (other than the financial statements and related schedules
therein, as to which such counsel need express no opinion) contains an untrue
statement of a material fact or omits to state a material fact necessary to
make the statements therein, in the light of the circumstances under which
they were ade, not misleading; and they do not know of any amendment to the
Registration Statement required to be filed or of any contracts or other
documents of a character required to be filed as an exhibit to the
Registration Statement or required to be incorporated by reference into the
Prospectus or required to be described in the Registration Statement or the
Prospectus which are not filed or incorporated by reference or described as
required;

          (d)  [Stern, Kessler, Goldstein & Fox] patent counsel to the Company,
and Marc H. Bozeman, regulatory counsel for the Company, shall have furnished to
you their respective written opinions (a draft of each such opinion is attached
hereto as Annex II(c) and II(d) hereto, respectively) dated such Time of
Delivery, in form and substance satisfactory to you, and as to such patent
counsel's opinion, to the effect that;

               (i)     the statements in the Registration Statement and the
Prospectus under the captions "Risk Factors - Patents and Proprietary Rights;
Access to Proprietary Genes and Proteins," "Business - Patents and Proprietary
Rights" and "Business - Access to Proprietary Genes" to the best of such
counsel's knowledge and belief, are accurate and complete statements or
summaries of the matters therein set forth and nothing has come to such
counsel's attention that causes such counsel to believe that the above-described
portions of (a) the Registration Statement contain any untrue statement of a
material fact or omitted to state a material fact necessary to make the
statements therein not misleading; and (b) the Prospectus contain any untrue
statement of a material fact or omit to state a material fact necessary in order
to make the statements made, in light of the circumstances under which they were
made, not misleading;

               (ii)    except for patent and trademark applications pending in
governmental patent offices, to the best of such counsel's knowledge, there are
no legal or governmental proceedings pending relating to patent rights, trade
secrets, trademarks, service marks or other proprietary information or materials
of the Company, and except for pending or future patent and trademark
applications, to the best of such counsel's knowledge no such proceedings are
threatened or contemplated by governmental authorities or others;

               (iii)   except as set forth in the Registration Statement and
the Prospectus, and except for certain investigational uses, to the best of such
counsel's knowledge, the Company is not infringing or otherwise violating any
patents, trade secrets, trademarks, service marks or other proprietary
information or materials, of others, and to the best of such counsel's knowledge
there are no infringements by others of any of the Company's patents, trade
secrets, trademarks, service marks or other proprietary information or materials
which in the judgment of such counsel could affect materially the use thereof by
the Company; and


                                     14.



               (iv)    except as set forth in the Registration Statement and
the Prospectus, to the best of such counsel's knowledge, the Company owns or
possesses sufficient licenses or other rights to use all patents, trade secrets,
trademarks, service marks, or other proprietary information or materials
necessary to conduct the business now being or proposed to be conducted by the
Company as described in the Prospectus.

          (e)  On the date of the Prospectus at a time prior to the execution of
this Agreement, at 9:30 a.m., New York City time, on the effective date of any
post-effective amendment to the Registration Statement filed subsequent to the
date of this Agreement and also at each Time of Delivery, Arthur Andersen LLP
shall have furnished to you a letter or letters, dated the respective dates of
delivery thereof, in form and substance satisfactory to you, to the effect set
forth in Annex I hereto (the executed copy of the letter delivered prior to the
execution of this Agreement is attached as Annex I(a) hereto and a draft of the
form of letter to be delivered on the effective date of any post-effective
amendment to the Registration Statement and as of each Time of Delivery is
attached as Annex I(b) hereto);

          (f)  (i)     Neither the Company nor any of its subsidiaries shall
have sustained since the date of the latest audited financial statements
included or incorporated by reference in the Prospectus any loss or interference
with its business from fire, explosion, flood or other calamity, whether or not
covered by insurance, or from any labor dispute or court or governmental action,
order or decree, otherwise than as set forth or contemplated in the Prospectus,
and (ii) since the respective dates as of which information is given in the
Prospectus there shall not have been any change in the capital stock or
long-term debt of the Company or any of its subsidiaries or any change, or any
development involving a prospective change, in or affecting the general affairs,
management, financial position, stockholders' equity or results of operations of
the Company and its subsidiaries, otherwise than as set forth or contemplated in
the Prospectus, the effect of which, in any such case described in clause (i) or
(ii), is in the judgment of the Representatives so material and adverse as to
make it impracticable or inadvisable to proceed with the public offering or the
delivery of the Shares being delivered at such Time of Delivery on the terms and
in the manner contemplated in the Prospectus;

          (g)  On or after the date hereof there shall not have occurred any of
the following: (i) a suspension or material limitation in trading in securities
generally on the NASDAQ; (ii) a suspension or material limitation in trading in
the Company's securities on the NASDAQ; (iii) a general moratorium on commercial
banking activities declared by either Federal or New York or California State
authorities; or (iv) the outbreak or escalation of hostilities involving the
United States or the declaration by the United States of a national emergency or
war, if the effect of any such event specified in this clause (iv) in the
judgment of the Representatives makes it impracticable or inadvisable to proceed
with the public offering or the delivery of the Shares being delivered at such
Time of Delivery on the terms and in the manner contemplated in the Prospectus;

          (h)  The Shares at such Time of Delivery shall have been duly listed
for quotation on the NASDAQ; and


                                     15.



          (i)  The Company has obtained and delivered to the Underwriters
executed copies of an agreement from each officer and director of the Company
and entities affiliated therewith, substantially to the effect set forth in
Subsection 5(e) hereof in form and substance satisfactory to you;

          (j)  The Company shall have complied with the provisions of Section
5(c) hereof with respect to the furnishing of prospectuses on the New York
Business Day next succeeding the date of this Agreement; and

          (k)  The Company shall have furnished or caused to be furnished to you
at such Time of Delivery certificates of officers of the Company satisfactory to
you as to the accuracy of the representations and warranties of the Company
herein at and as of such Time of Delivery, as to the performance by the Company
of all of its obligations hereunder to be performed at or prior to such Time of
Delivery, and as to such other matters as you may reasonably request, and the
Company shall have furnished or caused to be furnished certificates as to the
matters set forth in subsections (a) and (f) of this Section.

     8.   (a)  The Company will indemnify and hold harmless each Underwriter
against any losses, claims, damages or liabilities, joint or several, to which
such Underwriter may become subject, under the Act or otherwise, insofar as such
losses, claims, damages or liabilities (or actions in respect thereof) arise out
of or are based upon an untrue statement or alleged untrue statement of a
material fact contained in any Preliminary Prospectus, the Registration
Statement or the Prospectus, or any amendment or supplement thereto, or arise
out of or are based upon the omission or alleged omission to state therein a
material fact required to be stated therein or necessary to make the statements
therein not misleading, and will reimburse each Underwriter for any legal or
other expenses reasonably incurred by such Underwriter in connection with
investigating or defending any such action or claim as such expenses are
incurred; PROVIDED, HOWEVER, that the Company shall not be liable in any such
case to the extent that any such loss, claim, damage or liability arises out of
or is based upon an untrue statement or alleged untrue statement or omission or
alleged omission made in any Preliminary Prospectus, the Registration Statement
or the Prospectus or any such amendment or supplement in reliance upon and in
conformity with written information furnished to the Company by any Underwriter
through Goldman, Sachs & Co. expressly for use therein.

          (b)  Each Underwriter will indemnify and hold harmless the Company
against any losses, claims, damages or liabilities to which the Company may
become subject, under the Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon an untrue statement or alleged untrue statement of a material fact
contained in any Preliminary Prospectus, the Registration Statement or the
Prospectus, or any amendment or supplement thereto, or arise out of or are based
upon the omission or alleged omission to state therein a material fact required
to be stated therein or necessary to make the statements therein not misleading,
in each case to the extent, but only to the extent, that such untrue statement
or alleged untrue statement or omission or alleged omission was made in any
Preliminary Prospectus, the Registration Statement or the Prospectus or any such
amendment or supplement in reliance upon and in conformity with written
information furnished to the Company by such Underwriter through Goldman, Sachs
& Co. expressly for use therein; and will reimburse the Company for any legal or
other expenses reasonably


                                     16.



incurred by the Company in connection with investigating or defending any
such action or claim as such expenses are incurred.

          (c)  Promptly after receipt by an indemnified party under subsection
(a) or (b) above of notice of the commencement of any action, such indemnified
party shall, if a claim in respect thereof is to be made against the
indemnifying party under such subsection, notify the indemnifying party in
writing of the commencement thereof; but the omission so to notify the
indemnifying party shall not relieve it from any liability which it may have to
any indemnified party otherwise than under such subsection.  In case any such
action shall be brought against any indemnified party and it shall notify the
indemnifying party of the commencement thereof, the indemnifying party shall be
entitled to participate therein and, to the extent that it shall wish, jointly
with any other indemnifying party similarly notified, to assume the defense
thereof, with counsel satisfactory to such indemnified party (who shall not,
except with the consent of the indemnified party, be counsel to the indemnifying
party), and, after notice from the indemnifying party to such indemnified party
of its election so to assume the defense thereof, the indemnifying party shall
not be liable to such indemnified party under such subsection for any legal
expenses of other counsel or any other expenses, in each case subsequently
incurred by such indemnified party, in connection with the defense thereof other
than reasonable costs of investigation.  No indemnifying party shall, without
the written consent of the indemnified party, effect the settlement or
compromise of, or consent to the entry of any judgment with respect to, any
pending or threatened action or claim in respect of which indemnification or
contribution may be sought hereunder (whether or not the indemnified party is an
actual or potential party to such action or claim) unless such settlement,
compromise or judgment (i) includes an unconditional release of the indemnified
party from all liability arising out of such action or claim and (ii) does not
include a statement as to or an admission of fault, culpability or a failure to
act, by or on behalf of any indemnified party.

          (d)  If the indemnification provided for in this Section 8 is
unavailable to or insufficient to hold harmless an indemnified party under
subsection (a) or (b) above in respect of any losses, claims, damages or
liabilities (or actions in respect thereof) referred to therein, then each
indemnifying party shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages or liabilities (or
actions in respect thereof) in such proportion as is appropriate to reflect the
relative benefits received by the Company and the Selling Stockholders on the
one hand and the Underwriters on the other from the offering of the Shares.  If,
however, the allocation provided by the immediately preceding sentence is not
permitted by applicable law or if the indemnified party failed to give the
notice required under subsection (c) above, then each indemnifying party shall
contribute to such amount paid or payable by such indemnified party in such
proportion as is appropriate to reflect not only such relative benefits but also
the relative fault of the Company on the one hand and the Underwriters on the
other in connection with the statements or omissions which resulted in such
losses, claims, damages or liabilities (or actions in respect thereof), as well
as any other relevant equitable considerations.  The relative benefits received
by the Company on the one hand and the Underwriters on the other shall be deemed
to be in the same proportion as the total net proceeds from the offering (before
deducting expenses) received by the Company bear to the total underwriting
discounts and commissions received by the Underwriters, in each case as set
forth in the table on the cover page of the Prospectus.  The relative fault
shall be determined by reference to,


                                     17.



among other things, whether the untrue or alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company on the one hand or the
Underwriters on the other an the parties' relative intent, knowledge, access
to information and opportunity to correct or prevent such statement or
omission.  The Company and the Underwriters agree that it would not be just
and equitable if contributions pursuant to this subsection (d) were
determined by PRO RATA allocation (even if the Underwriters were treated as
one entity for such purpose) or by any other method of allocation which does
not take account of the equitable considerations referred to above in this
subsection (d).  The amount paid or payable by an indemnified party as a
result of the losses, claims, damages or liabilities (or actions in respect
thereof) referred to above in this subsection (d) shall be deemed to include
any legal or other expenses reasonably incurred by such indemnified party in
connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this subsection (d), no Underwriter shall
be required to contribute any amount in excess of the amount by which the
total price at which the Shares underwritten by it and distributed to the
public were offered to the public exceeds the amount of any damages which
such Underwriter has otherwise been required to pay by reason of such untrue
or alleged untrue statement or omission or alleged omission.  No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f)
of the Act) shall be entitled to contribution from any person who was not
guilty of such fraudulent misrepresentation.  The Underwriters' obligations
in this subsection (d) to contribute are several in proportion to their
respective underwriting obligations and not joint.

          (e)  The obligations of the Company under this Section 8 shall be in
addition to any liability which the Company may otherwise have and shall extend,
upon the same terms and conditions, to each person, if any, who controls any
Underwriter within the meaning of the Act; and the obligations of the
Underwriters under this Section 8 shall be in addition to any liability which
the respective Underwriters may otherwise have and shall extend, upon the same
terms and conditions, to each officer and director of the Company and to each
person, if any, who controls the Company or any Selling Stockholder within the
meaning of the Act.

     9.   (a)  If any Underwriter shall default in its obligation to purchase
the Shares which it has agreed to purchase hereunder at a Time of Delivery, you
may in your discretion arrange for you or another party or other parties to
purchase such Shares on the terms contained herein.  If within thirty-six hours
after such default by any Underwriter you do not arrange for the purchase of
such Shares, then the Company and shall be entitled to a further period of
thirty-six hours within which to procure another party or other parties
satisfactory to you to purchase such Shares on such terms.  In the event that,
within the respective prescribed periods, you notify the Company that you have
so arranged for the purchase of such Shares, or the Company notifies you that
they have so arranged for the purchase of such Shares, you or the Company shall
have the right to postpone a Time of Delivery for a period of not more than
seven days, in order to effect whatever changes may thereby be made necessary in
the Registration Statement or the Prospectus, or in any other documents or
arrangements, and the Company agrees to file promptly any amendments to the
Registration Statement or the Prospectus which in your opinion may thereby be
made necessary.  The term "Underwriter" as used in this Agreement shall include
any person substituted under this Section with like effect as if such person had
originally been a party to this Agreement with respect to such Shares.


                                      18.


          (b)  If, after giving effect to any arrangements for the purchase of
the Shares of a defaulting Underwriter or Underwriters by you and the Company as
provided in subsection (a) above, the aggregate number of such Shares which
remains unpurchased does not exceed one-eleventh of the aggregate number of all
the Shares to be purchased at such Time of Delivery, then the Company shall have
the right to require each non-defaulting Underwriter to purchase the number of
Shares which such Underwriter agreed to purchase hereunder at such Time of
Delivery and, in addition, to require each non-defaulting Underwriter to
purchase its pro rata share (based on the number of Shares which such
Underwriter agreed to purchase hereunder) of the Shares of such defaulting
Underwriter or Underwriters for which such arrangements have not been made; but
nothing herein shall relieve a defaulting Underwriter from liability for its
default.

          (c)  If, after giving effect to any arrangements for the purchase of
the Shares of a defaulting Underwriter or Underwriters by you and the Company as
provided in subsection (a) above, the aggregate number of such Shares which
remains unpurchased exceeds one-eleventh of the aggregate number of all of the
Shares to be purchased at such Time of Delivery, or if the Company shall not
exercise the right described in subsection (b) above to require non-defaulting
Underwriters to purchase Shares of a defaulting Underwriter or Underwriters,
then this Agreement (or, with respect to the Second Time of Delivery, the
obligations of the Underwriters to purchase and of the Company to sell the
Optional Shares) shall thereupon terminate, without liability on the part of any
non-defaulting Underwriter or the Company, except for the expenses to be borne
by the Company and the Underwriters as provided in Section 6 hereof and the
indemnity and contribution agreements in Section 8 hereof; but nothing herein
shall relieve a defaulting Underwriter from liability for its default.

     10.  The respective indemnities, agreements, representations, warranties
and other statements of the Company and the several Underwriters, as set forth
in this Agreement or made by or on behalf of them, respectively, pursuant to
this Agreement, shall remain in full force and effect, regardless of any
investigation (or any statement as to the results thereof) made by or on behalf
of any Underwriter or any controlling person of any Underwriter, or the Company,
or any officer or director or controlling person of the Company, and shall
survive delivery of and payment for the Shares.

     11.  If this Agreement shall be terminated pursuant to Section 9 hereof,
the Company shall not then be under any liability to any Underwriter except as
provided in Sections 6 and 8 hereof; but, if for any other reason any Shares are
not delivered by or on behalf of the Company as provided herein, the Company
will reimburse the Underwriters through you for all out-of-pocket expenses
approved in writing by you, including fees and disbursements of counsel,
reasonably incurred by the Underwriters in making preparations for the purchase,
sale and delivery of the Shares not so delivered, but the Company shall then be
under no further liability to any Underwriter in respect of the Shares not so
delivered except as provided in Sections 6 and 8 hereof.

     12.  In all dealings hereunder, you shall act on behalf of each of the
Underwriters, and the parties hereto shall be entitled to act and rely upon any
statement, request, notice or agreement on behalf of any Underwriter made or
given by you jointly or by Goldman, Sachs & Co. on behalf of you as the
representatives.


                                     19.



     All statements, requests, notices and agreements hereunder shall be in
writing, and if to the Underwriters shall be delivered or sent by mail, telex or
facsimile transmission to you as the representatives in care of Goldman, Sachs &
Co., 32 Old Slip, 21st Floor, New York, New York 10005, Attention: Registration
Department; if to any Selling Stockholder shall be delivered or sent by mail,
telex or facsimile transmission to counsel for such Selling Stockholder at its
address set forth in Schedule II hereto; and if to the Company shall be
delivered or sent by mail, telex or facsimile transmission to the address of the
Company set forth in the Registration Statement, Attention: Secretary; provided,
however, that any notice to an Underwriter pursuant to Section 8(c) hereof shall
be delivered or sent by mail, telex or facsimile transmission to such
Underwriter at its address set forth in its Underwriters' Questionnaire or telex
constituting such Questionnaire, which address will be supplied to the Company
by you on request.  Any such statements, requests, notices or agreements shall
take effect upon receipt thereof.

     13.  This Agreement shall be binding upon, and inure solely to the benefit
of, the Underwriters, the Company and, to the extent provided in Sections 8 and
10 hereof, the officers and directors of the Company and each person who
controls the Company, any Underwriter, and their respective heirs, executors,
administrators, successors and assigns, and no other person shall acquire or
have any right under or by virtue of this Agreement.  No purchaser of any of the
Shares from any Underwriter shall be deemed a successor or assign by reason
merely of such purchase.

     14.  Time shall be of the essence of this Agreement.  As used herein, the
term "business day" shall mean any day when the Commission's office in
Washington, D.C.  is open for business.

     15.  THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

     16.  This Agreement may be executed by any one or more of the parties
hereto in any number of counterparts, each of which shall be deemed to be an
original, but all such counterparts shall together constitute one and the same
instrument.

               [THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]



                                     20.



     If the foregoing is in accordance with your understanding, please sign and
return to us one for the Company and each of the Representatives counterparts
hereof, and upon the acceptance hereof by you, on behalf of each of the
Underwriters, this letter and such acceptance hereof shall constitute a binding
agreement among each of the Underwriters and the Company.  It is understood that
your acceptance of this letter on behalf of each of the Underwriters is pursuant
to the authority set forth in a form of Agreement among Underwriters, the form
of which shall be submitted to the Company for examination, upon request, but
without warranty on your part as to the authority of the signers thereof.

                                        Very truly yours,

                                        VICAL INCORPORATED

                                        By:___________________________________

                                        Name:_________________________________

                                        Title:________________________________


Accepted as of the date hereof:

Goldman, Sachs & Co.
BancBoston Robertson Stephens
SG Cowen Securities Corporation
First Union Securities, Inc.

 By:____________________________________
      (Goldman, Sachs & Co.)

On behalf of each of the Underwriters


                                     21.






                                      SCHEDULE I

                                                                           NUMBER OF
                                                                            OPTIONAL
                                                                          SHARES TO BE
                                                                          PURCHASED IF
                                          TOTAL NUMBER OF                    MAXIMUM
                                         FIRM SHARES TO BE                   OPTION
       UNDERWRITER                          PURCHASED                       EXERCISED
- ----------------------------------------------------------------------------------------
                                                                    
 Goldman, Sachs & Co.................

 BancBoston Robertson Stephens ......

 SG Cowen Securities Corporation.....

 First Union Securities, Inc. .......

 [NAMES OF OTHER UNDERWRITERS].......
                                        ------------------                ---------------
      Total..........................
                                        ==================                ===============




                                  Schedule I




                                    SCHEDULE II




                                                                  NUMBER OF
                                               TOTAL NUMBER OF  OPTIONAL SHARES
                                                FIRM SHARES TO   TO BE SOLD IF
                                                   BE SOLD       MAXIMUM OPTION
                                                                   EXERCISED
- -------------------------------------------------------------------------------
                                                           
 The Company..............................       [2,500,000]       [375,000]
                                               --------------    --------------
 Total....................................       [2,500,000]       [375,000]
                                               ==============    ==============


                                  Schedule II



                                                                         ANNEX I

     Pursuant to Section 7(d) of the Underwriting Agreement, the accountants
shall furnish letters to the Underwriters to the effect that:

               (i)  They are independent certified public accountants with
respect to the Company and its subsidiaries within the meaning of the Act and
the applicable published rules and regulations thereunder;

               (ii) In their opinion, the financial statements and any
supplementary financial information and schedules (and, if applicable, financial
forecasts and/or pro forma financial information) examined by them and included
or incorporated by reference in the Registration Statement or the Prospectus
comply as to form in all material respects with the applicable accounting
requirements of the Act or the Exchange Act, as applicable, and the related
published rules and regulations thereunder; and, if applicable, they have made a
review in accordance with standards established by the American Institute of
Certified Public Accountants of the consolidated interim financial statements,
selected financial data, pro forma financial information, financial forecasts
and/or condensed financial statements derived from audited financial statements
of the Company for the periods specified in such letter, as indicated in their
reports thereon, copies of which have been separately furnished to the
representatives of the Underwriters (the "Representatives") and are attached
hereto;

               (iii)     They have made a review in accordance with standards
established by the American Institute of Certified Public Accountants of the
unaudited condensed consolidated statements of income, consolidated balance
sheets and consolidated statements of cash flows included in the Prospectus
and/or included in the Company's quarterly report on Form 10-Q incorporated by
reference into the Prospectus as indicated in their reports thereon copies of
which have been separately furnished to the Representatives; and on the basis of
specified procedures including inquiries of officials of the Company who have
responsibility for financial and accounting matters regarding whether the
unaudited condensed consolidated financial statements referred to in paragraph
(vi)(A)(i) below comply as to form in all material respects with the applicable
accounting requirements of the Act and the Exchange Act and the related
published rules and regulations, nothing came to their attention that caused
them to believe that the unaudited condensed consolidated financial statements
do not comply as to form in all material respects with the applicable accounting
requirements of the Act and the Exchange Act and the related published rules and
regulations;

               (iv) The unaudited selected financial information with
respect to the consolidated results of operations and financial position of the
Company for the five most recent fiscal years included in the Prospectus and
included or incorporated by reference in Item 6 of the Company's Annual Report
on Form 10-K for the most recent fiscal year agrees with the corresponding
amounts (after restatement where applicable) in the audited consolidated
financial statements for such five fiscal years which were included or
incorporated by reference in the Company's Annual Reports on Form 10-K for such
fiscal years;

               (v)  They have compared the information in the Prospectus
under selected captions with the disclosure requirements of Regulation S-K and
on the basis of limited

                                   Annex 1


                                     1.



procedures specified in such letter nothing came to
their attention as a result of the foregoing procedures that caused them to
believe that this information does not conform in all material respects with the
disclosure requirements of Items 301, 302, 402 and 503(d), respectively, of
Regulation S-K;

               (vi) On the basis of limited procedures, not constituting an
examination in accordance with generally accepted auditing standards, consisting
of a reading of the unaudited financial statements and other information
referred to below, a reading of the latest available interim financial
statements of the Company and its subsidiaries, inspection of the minute books
of the Company and its subsidiaries since the date of the latest audited
financial statements included or incorporated by reference in the Prospectus,
inquiries of officials of the Company and its subsidiaries responsible for
financial and accounting matters and such other inquiries and procedures as may
be specified in such letter, nothing came to their attention that caused them to
believe that:

                    (A)  (i) the unaudited condensed consolidated
statements of income, consolidated balance sheets and consolidated statements of
cash flows included in the Prospectus and/or included or incorporated by
reference in the Company's Quarterly Reports on Form 10-Q incorporated by
reference in the Prospectus do not comply as to form in all material respects
with the applicable accounting requirements of the Exchange Act as it applies to
Form 10-Q and the related published rules and regulations, or (ii) any material
modifications should be made to the unaudited condensed consolidated statements
of income, consolidated balance sheets and consolidated statements of cash flows
included in the Prospectus or included in the Company's Quarterly Reports on
Form 10-Q incorporated by reference in the Prospectus, for them to be conformity
with generally accepted accounting principles;

                    (B)  any other unaudited income statement data and
balance sheet items included in the Prospectus do not agree with the
corresponding items in the unaudited consolidated financial statements from
which such data and items were derived, and any such unaudited data and items
were not determined on a basis substantially consistent with the basis for the
corresponding amounts in the audited consolidated financial statements included
or incorporated by reference in the Company's Annual Report on Form 10-K for the
most recent fiscal year;

                    (C)  the unaudited financial statements which were not
included in the Prospectus but from which were derived the unaudited condensed
financial statements referred to in clause (A) and any unaudited income
statement data and balance sheet items included in the Prospectus and referred
to in clause (B) were not determined on a basis substantially consistent with
the basis for the audited financial statements included or incorporated by
reference in the Company's Annual Report on Form 10-K for the most recent fiscal
year;

                    (D)  any unaudited pro forma consolidated condensed
financial statements included or incorporated by reference in the Prospectus do
not comply as to form in all material respects with the applicable accounting
requirements of the Act and the published

                                   Annex 1


                                     2.



rules and regulations thereunder or the pro forma adjustments have not been
properly applied to the historical amounts in the compilation of those
statements;

                    (E)  as of a specified date not more than five days
prior to the date of such letter, there have been any changes in the
consolidated capital stock (other than issuances of capital stock upon exercise
of options and stock appreciation rights, upon earn-outs of performance shares
and upon conversions of convertible securities, in each case which were
outstanding on the date of the latest balance sheet included or incorporated by
reference in the Prospectus) or any increase in the consolidated long-term debt
of the Company and its subsidiaries, or any decreases in consolidated net
current assets or stockholders' equity or other items specified by the
Representatives, or any increases in any items specified by the Representatives,
in each case as compared with amounts shown in the latest balance sheet included
or incorporated by reference in the Prospectus, except in each case for changes,
increases or decreases which the Prospectus discloses have occurred or may occur
or which are described in such letter; and

                    (F)  for the period from the date of the latest
financial statements included or incorporated by reference in the Prospectus to
the specified date referred to in clause (E) there were any decreases in
consolidated net revenues or operating profit or the total or per share amounts
of consolidated net income or other items specified by the Representatives, or
any increases in any items specified by the Representatives, in each case as
compared with the comparable period of the preceding year and with any other
period of corresponding length specified by the Representatives, except in each
case for increases or decreases which the Prospectus discloses have occurred or
may occur or which are described in such letter; and

               (vii)     In addition to the examination referred to in their
report(s) included or incorporated by reference in the Prospectus and the
limited procedures, inspection of minute books, inquiries and other procedures
referred to in paragraphs (iii) and (vi) above, they have carried out certain
specified procedures, not constituting an examination in accordance with
generally accepted auditing standards, with respect to certain amounts,
percentages and financial information specified by the Representatives which are
derived from the general accounting records of the Company and its subsidiaries,
which appear in the Prospectus (excluding documents incorporated by reference)
or in Part II of, or in exhibits and schedules to, the Registration Statement
specified by the Representatives or in documents incorporated by reference in
the Prospectus specified by the Representatives, and have compared certain of
such amounts, percentages and financial information with the accounting records
of the Company and its subsidiaries and have found them to be in agreement.

                                   Annex 1


                                     3.