THIS NON-EXCLUSIVE LICENSE AGREEMENT, dated as of September 9, 1998 (the
"Effective Date") is made by and between IXSYS, INC., a Delaware corporation
("Ixsys"), and BIOSITE DIAGNOSTICS INCORPORATED, a Delaware corporation

       WHEREAS, Ixsys and Biosite have entered into that certain Research and
Development Agreement dated as of July 1, 1992 (the "R&D Agreement") pursuant to
which Ixsys granted to Biosite licenses to certain patent rights and related
know-how for the manufacture, use and sale of antibodies;

       WHEREAS, Ixsys and Biosite wish to terminate the R&D Agreement; and

       WHEREAS, Ixsys wishes to grant to Biosite, and Biosite wishes to obtain
from Ixsys, a non-exclusive license under certain patent rights and related
know-how held by Ixsys on the terms and subject to the conditions set forth

       NOW, THEREFORE, in consideration of the mutual covenants and promises
hereinafter set forth, the parties hereto hereby agree as follows:

                                    ARTICLE 1

       1.1 "AFFILIATE" means any corporation or other entity which controls, is
controlled by, or is under common control with, a party. A corporation or other
entity shall be regarded as in control of another corporation or entity if it
owns or directly or indirectly controls 50% or more of the voting stock or other
ownership interest of the other corporation or entity, or if it possesses,
directly or indirectly, the power to direct or cause the direction of the
management and policies of the corporation or other entity.

       1.2 "BIOSITE FIELD" means all research purposes and all in vitro
diagnostic purposes.

       1.3 "CONFIDENTIAL INFORMATION" means any confidential information of a
party, including information related to the Ixsys Technology, and any other
information relating to any compound, research project, work in process, future
development, scientific, engineering, manufacturing, marketing, business plan,
financial or personnel matter relating to such party, its present or future
products, sales, suppliers, customers, employees, investors or business, whether
in oral, written, graphic or electronic form. Confidential Information shall not
include any information which the receiving party can prove by competent

<PAGE>   2

       (a) is now, or hereafter becomes, through no act or failure to act on the
part of the receiving party, generally known or available;

       (b) is known by the receiving party at the time of receiving such
information, as evidenced by its records;

       (c) is hereafter furnished to the receiving party by a Third Party, as a
matter of right and without restriction on disclosure;

       (d) is independently developed by the receiving party without knowledge
of, and without the aid, application or use of, the disclosing party's
Confidential Information; or

       (e) is the subject of a written permission to disclose provided by the
disclosing party.

       1.4 "CONTROL" means possession of the ability to grant a license or
sublicense as provided for herein without violating the terms of any agreement
or other arrangement with any Third Party.

       1.5 "IXSYS KNOW-HOW" means all Know-How, owned by or under the Control of
Ixsys as of the Effective Date, which is not covered by the Ixsys Patent Rights,
but which is necessary or useful for the commercial exploitation of the Ixsys
Patent Rights.

       1.6 "IXSYS PATENT RIGHTS" means all rights under the patents and patent
applications set forth on Exhibit A, owned by or under the Control of Ixsys as
of the Effective Date, including any and all patents issuing therefrom and any
and all substitutions, extensions (including supplemental protection
certificates), registrations, confirmations, continuations,
continuations-in-part, divisionals, re-examinations, renewals, reissues and
foreign counterparts of the aforementioned.

       1.7 "IXSYS TECHNOLOGY" means the Ixsys Patent Rights and the Ixsys

       1.8 "KAUFFMAN AGREEMENT" means that certain License Agreement between
Stuart A. Kauffman, M.D. and Ixsys dated as of November 3, 1994, a copy of which
is attached hereto as Exhibit B.

       1.9 "KNOW-HOW" means all know-how, knowledge, trade secrets, inventions,
data, materials, techniques, practices, processes, procedures, devices, methods,
formulas, protocols and proprietary information, whether or not patentable,
which are not generally publicly known, including, without limitation, all
chemical, biochemical, toxicological and scientific research information.

       1.10 "PRODUCT" means any product or service, the development,
manufacture, use or sale of which is covered by, uses or incorporates any Ixsys

       1.11 "STRATAGENE AGREEMENT" means that certain Master Agreement between
Stratagene Cloning Systems, Inc., Stratacyte Corporation, William D. Huse and
Ixsys dated as of November 7, 1991, a copy of which is attached hereto as
Exhibit C.

<PAGE>   3

       1.12 "TERM" shall have the meaning set forth in Section 5.1.

       1.13 "THIRD PARTY" means any entity other than Biosite or Ixsys or an
Affiliate of Biosite or Ixsys.

                                    ARTICLE 2
                       GRANT OF LICENSE; ROYALTY PAYMENT;
                          TERMINATION OF R&D AGREEMENT

       2.1 LICENSE GRANT. Subject to the terms and conditions of this Agreement
and during the Term, Ixsys hereby grants to Biosite a non-exclusive, worldwide,
fully-paid, perpetual, irrevocable license under the Ixsys Technology to
develop, make, have made, use, offer for sale, sell and import Products in the
Biosite Field.

       2.2 THIRD PARTY SALE OR PRODUCTION. Notwithstanding anything to the
contrary in this Agreement, Biosite shall have the right, in connection with a
transaction or arrangement with a Third Party relating to any product or service
relating to the Biosite Field, to grant to such Third Party the right to
produce, use, provide and sell such product or service derived from hosts
provided by Biosite; provided, however, that any such Third Party shall have no
other right, title or license under the Ixsys Technology.

       2.3 SUBLICENSES. Biosite shall have the right to grant sublicenses to its
Affiliates only. Biosite shall notify any sublicensee hereunder of all rights
and obligations of Biosite under this Agreement which are sublicensed to such
sublicensee and shall notify Ixsys within 30 days of the grant of any sublicense
hereunder. Biosite shall remain primarily liable under this Agreement
irrespective of any sublicense granted hereunder.

       2.4 SUBLICENSE OBLIGATIONS. Biosite hereby agrees to be bound by the
terms and conditions expressly applicable to a sublicensee under the Kauffman
Agreement and the Stratagene Agreement.

       2.5 UP-FRONT ROYALTY PAYMENT. In full consideration for the license grant
in Section 2.1, Biosite shall pay to Ixsys *** upon the Effective Date.

       2.6 TERMINATION OF R&D AGREEMENT. Ixsys and Biosite hereby terminate the
R&D Agreement as of the Effective Date with the effect of termination specified
therein (subject to the rights and licenses granted herein); provided, however,
that the parties agree that there are no outstanding debts or obligations or
claims under the R&D Agreement, except for the surviving provisions expressly
referred to in the second and third sentences of Section 11.3 thereof. For
avoidance of doubt, Ixsys has, and will have, ***.

                                    ARTICLE 3

       During the Term and for a period of five years thereafter, each party
will maintain all Confidential Information of the other party as confidential
and will not disclose any Confidential Information of the other party to any
Third Party or use any Confidential Information of the other party for any
purpose, except (a) as authorized by this Agreement, (b) as required by law,
rule, regulation or court order (provided that the disclosing party shall use
commercially reasonable

*** Confidential Treatment has been requested with respect to certain portions
of this agreement.

<PAGE>   4

efforts to obtain confidential treatment of any such information required to be
disclosed), or (c) to its Affiliates, employees, agents, consultants and other
representatives to accomplish the purposes of this Agreement so long as such
persons are under an obligation of confidentiality no less stringent than as set
forth herein. Each party may use such Confidential Information only to the
extent required to accomplish the purposes of this Agreement. Each party will
use at least the same standard of care as it uses to protect its own
Confidential Information to ensure that its Affiliates, employees, agents,
consultants and other representatives do not disclose or make any unauthorized
use of Confidential Information of the other party. Each party will promptly
notify the other upon discovery of any unauthorized use or disclosure of the
Confidential Information of the other party.

                                    ARTICLE 4

       4.1 CORPORATE POWER. Each party hereby represents and warrants that it is
duly organized and validly existing under the laws of the State of Delaware and
has full corporate power and authority to enter into this Agreement and to carry
out the provisions hereof.

       4.2 DUE AUTHORIZATION. Each party hereby represents and warrants that
such party is duly authorized to execute and deliver this Agreement and to
perform its obligations hereunder.

       4.3 BINDING AGREEMENT. Each party hereby represents and warrants that
this Agreement is a legal and valid obligation binding upon it and is
enforceable in accordance with its terms. The execution, delivery and
performance of this Agreement by such party does not conflict with any
agreement, instrument or understanding, oral or written, to which it is a party
or by which it may be bound, nor violate any law or regulation of any court,
governmental body or administrative or other agency having authority over it.

       4.4 IXSYS PATENT RIGHTS. Ixsys hereby represents and warrants that (a)
all patents and patent applications set forth on Exhibit A are owned by or under
the Control of Ixsys as of the Effective Date, and (b) to the best of its
knowledge, the Ixsys Patent Rights include all patent rights owned by or under
the Control of Ixsys as of the Effective Date applicable to the Biosite Field as
of the Effective Date.

       4.5 SUBLICENSED PATENT RIGHTS. Ixsys represents and warrants that (a)
Ixsys shall be fully and solely responsible for all payment obligations under
the Kauffman Agreement and the Stratagene Agreement in connection with the
license granted to Biosite hereunder and for otherwise fully maintaining all
relevant licenses and arrangements with third parties such that all licenses and
sublicenses granted to Biosite hereunder remain fully in effect without any
payment by Biosite to Ixsys or anyone else, except as specified in Section 2.5,
(b) Ixsys has provided to Biosite copies of all written agreements related to
the Kauffman Agreement and the Stratagene Agreement (including, without
limitation, any amendments thereto and any agreements attached as exhibits
thereto), (c) the Kauffman Agreement and the Stratagene Agreement are in effect
and in good standing as of the Effective Date, (d) Ixsys shall notify Biosite
promptly in writing of the occurrence of any potential event of which Ixsys
becomes aware which may result in the termination of the Kauffman Agreement or
the Stratagene Agreement or which may limit any right granted to Biosite
hereunder, and (e) the Kauffman Agreement and the Stratagene

<PAGE>   5

Agreement are the only agreements under which Ixsys has received a license to
any of the Ixsys Patent Rights or Ixsys Know How.

       4.6 KNOW-HOW LICENSED TO BIOSITE. Ixsys hereby represents and warrants
that any Know-How previously provided to Biosite under the R&D Agreement is
owned by or under the Control of Ixsys as of the Effective Date.



       4.9 INDEMNIFICATION. Biosite hereby agrees to save, defend, indemnify and
hold harmless Ixsys and its directors, officers, employees, agents, consultants
and other representatives from and against any and all losses, damages,
liabilities, expenses and costs, including reasonable legal expense and
attorneys' fees ("Losses"), to which Ixsys may become subject as a direct result
of any claim, demand, action or other proceeding by any Third Party to the
extent such Losses arise directly out of the practice by Biosite of the license
granted hereunder, except to the extent such Losses result from the negligence
or the willful misconduct of Ixsys. In the event Ixsys seeks indemnification
under this Section 4.9, and as a condition thereof, Ixsys shall inform Biosite
of a claim as soon as reasonably practicable after Ixsys receives notice of the
claim, shall permit Biosite to assume direction and control of the defense and
settlement of the claim (including the right to settle the claim solely for
monetary consideration), and shall cooperate as requested (at the expense of
Biosite) in the defense and settlement of the claim. The indemnification
provided under this Section 4.9 shall supersede any surviving indemnification
obligation of Biosite under the R&D Agreement.

       4.10 FAIR VALUE. Ixsys represents and warrants that its Board of
Directors, after full disclosure and review of all relevant facts and
circumstances, has determined that this Agreement provides Ixsys with fair value
at least equivalent to the value it is providing under this Agreement, and,
accordingly, has approved this transaction.

                                    ARTICLE 5
                                TERM; TERMINATION

       5.1 TERM. This Agreement shall begin as of the Effective Date and shall
end upon the expiration of the last to expire of the Ixsys Patent Rights (the

       5.2 EFFECT OF EXPIRATION. Expiration of this Agreement shall not relieve
the parties of any obligation accruing prior to such expiration. The provisions
of Sections 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 and 5.2 and Articles 1, 3, and 6 shall
survive the expiration of this Agreement.

<PAGE>   6

                                    ARTICLE 6

       6.1 FORCE MAJEURE. Neither party shall be held liable or responsible to
the other party nor be deemed to have defaulted under or breached this Agreement
for failure or delay in fulfilling or performing any term of this Agreement
(except for non-payment) when such failure or delay is caused by or results from
causes beyond the reasonable control of the affected party, including, without
limitation, fire, floods, embargoes, war, acts of war (whether war be declared
or not), insurrections, riots, civil commotions, strikes, lockouts or other
labor disturbances, acts of God or acts, omissions or delays in acting by any
governmental authority or the other party.

       6.2 ASSIGNMENT. Except as expressly provided hereunder, neither this
Agreement nor any rights or obligations hereunder may be assigned or otherwise
transferred by either party without the prior written consent of the other party
(which consent shall not be unreasonably withheld); provided, however, that
either party may assign this Agreement and its rights and obligations hereunder
without the other party's consent (a) *** (b) to any Affiliate. Notwithstanding
the foregoing, any such assignment to an Affiliate shall not relieve the
assigning party of its responsibilities for performance of its obligations under
this Agreement. The rights and obligations of the parties under this Agreement
shall be binding upon and inure to the benefit of the successors and permitted
assigns of the parties. Any assignment not in accordance with this Agreement
shall be void.

       6.3 SEVERABILITY. In case any provision of this Agreement shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

       6.4 NOTICES. All notices and other communications provided for hereunder
shall be in writing and shall be mailed by first-class, registered or certified
mail, postage paid, or delivered personally, by overnight delivery service or by
facsimile, computer mail or other electronic means, with confirmation of
receipt, addressed as follows:

                            11030 Roselle Street, Suite D
                            San Diego, CA 92121
                            Attn: President
                            Fax No.  (619) 455-4815

       IF TO IXSYS:         IXSYS, INC.
                            3520 Dunhill Street
                            San Diego, CA 92121
                            Attn: President
                            Fax No.  (619) 597-4950

       Either party may by like notice specify or change an address to which
notices and communications shall thereafter be sent. Notices sent by facsimile,
computer mail or other electronic means shall be effective upon confirmation of
receipt, notices sent by mail or

*** Confidential Treatment has been requested with respect to certain portions
of this agreement.

<PAGE>   7

overnight delivery service shall be effective upon receipt, and notices given
personally shall be effective when delivered.

       6.5 GOVERNING LAW; VENUE. This Agreement shall be governed by, and
construed and enforced in accordance with, the laws of the State of California,
without regard to its choice of law provisions. Any action or proceeding arising
from or relating to this Agreement shall be brought in a federal court in the
Southern District of California or in a state court in San Diego County,
California, and each party irrevocably submits to the jurisdiction and venue of
any such court in any such action or proceeding.

       6.6 ATTORNEYS' AND EXPERTS' FEES. In any proceeding between the parties
arising from or related to the interpretation, construction or enforcement of
this Agreement, the prevailing party shall, in addition to recovering all costs
of suit, be entitled to an award of actual attorneys' fees and actual expert
witness' fees incurred, whether in an original action or on appeal.

       6.7 INJUNCTIVE RELIEF. Biosite agrees that Biosite's unauthorized use or
disclosure of any of Ixsys' Confidential Information received by Biosite will
cause irreparable injury to Ixsys for which pecuniary compensation would not
afford adequate relief and would be extremely difficult to ascertain. In
addition, notwithstanding any of the provisions of this Agreement, Ixsys shall
have the unequivocal right to obtain timely injunctive relief in the event
Biosite breaches its obligations under Article 2 of this Agreement.

       6.8 ENTIRE AGREEMENT; AMENDMENT. This Agreement sets forth all of the
covenants, promises, agreements, warranties, representations, conditions and
understandings between the parties hereto with respect to the subject matter of
this Agreement, and supersedes and terminates all prior agreements and
understanding between the parties with respect to the subject matter of this
Agreement. There are no covenants, promises, agreements, warranties,
representations conditions or understandings with respect to the subject matter
hereof, either oral or written, between the parties other than as set forth
herein. No subsequent alteration, amendment, change or addition to this
Agreement shall be binding upon the parties hereto unless reduced to writing and
signed by the respective authorized officers of the parties.

       6.9 HEADINGS. The captions contained in this Agreement are not a part of
this Agreement, but are merely guides or labels to assist in locating and
reading the several Articles hereof.

       6.10 INDEPENDENT CONTRACTORS. It is expressly agreed that Ixsys and
Biosite shall be independent contractors and that the relationship between the
two parties shall not constitute a partnership, joint venture or agency of any
kind. Neither party shall have the authority to make any statements,
representations or commitments of any kind, or to take any action, which shall
be binding on the other, without the prior written consent of the other party.

       6.11 WAIVER. Except as specifically provided for herein, the waiver from
time to time by either of the parties of any of their rights or their failure to
exercise any remedy shall not operate or be construed as a continuing waiver of
the same rights or remedies or of any other of such party's rights or remedies
provided in this Agreement.

<PAGE>   8

       6.12 COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

       IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first set forth above.

IXSYS, INC.                                    BIOSITE DIAGNOSTICS INCORPORATED

<S>                                              <C>
By:  /s/  Janine M. Taylor                     By:  /s/  Kim D. Blickenstaff
  --------------------------------------          --------------------------------------

Name:  Janine M. Taylor                        Name:  Kim D. Blickenstaff
    ------------------------------------            ------------------------------------

Title:  Chief Financial Officer                Title:  President
     -----------------------------------             -----------------------------------

                         Non-Exclusive license Agreement


Source: OneCLE Business Contracts.