<PAGE>

                                                                Exhibit 10.80

                          [CONFIDENTIAL TREATMENT REQUESTED]

[Certain information has been omitted herein pursuant to a request for 
confidential treatment pursuant to Rule 24b-2.]


                              CHIRON FUNDING L.L.C.

                       LIMITED LIABILITY COMPANY AGREEMENT


     THIS LIMITED LIABILITY COMPANY AGREEMENT (this ``Agreement") is entered
into and effective as of December 28, 1995 (the "Effective Date"), among Chiron
Corporation, a Delaware corporation ("Chiron"), Chiron Biocine Company and
Biocine S.p.A., both of which are wholly owned Affiliates of Chiron, and Ciba-
Geigy Corporation, a New York  corporation ("Ciba"), Chiron, its Affiliates and
Ciba are sometimes referred to herein as the "Members".

                                        I
                            FORMATION OF THE COMPANY

     I.1  FORMATION AND EFFECTIVE DATE.  The parties hereby agree to organize a
limited liability company (the ``Company") under the Delaware Limited Liability
Company Act, (the "Act").  Prior to execution of this Agreement, as the Initial
Member, Chiron has caused a Certificate of Formation conforming to the
requirements of the Act to be executed and filed with the Office of the
Secretary of State of the State of Delaware.  The Company shall commence
business on or about the Effective Date.

     1.2  NAME AND PRINCIPAL PLACE OF BUSINESS.  The name of the Company is
"Chiron Funding L.L.C.".  The principal place of business of the Company shall
be in such place or places as the Members determine from time to time, with the
initial such principal place of business being located in 4560 Horton Street,
Emeryville, California.

     1.3  AGREEMENT AMONG MEMBERS.  For and in consideration of the mutual
covenants herein contained and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Members hereby
agree to the terms and conditions of this Agreement, as it may from time to time
be amended in accordance with its terms.  Except to the extent a provision of
the Agreement expressly incorporates federal income tax rules by reference to
sections of the Code or Treasury Regulations or is expressly prohibited or
ineffective under the Act, the Agreement shall govern, even when inconsistent
with, or different from, the provisions of the Act or any other law or rule.

     1.4  SCOPE OF BUSINESS.  The Company may engage in any lawful business
permitted by the Act or the laws of any jurisdiction in which the Company may do
business.

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     The Company shall have the authority to do all things necessary or
convenient to accomplish its purpose and operate its business as described in
this Section 1.4, subject to the provisions of this Agreement.

     1.5  NO STATE-LAW PARTNERSHIP.  The Members intend that the Company not be
a partnership (including, without limitation, a limited partnership) or joint
venture, and that no Member be a partner or joint venturer of any other Member,
for any purposes other than federal and state tax purposes, and this Agreement
should not be construed to suggest otherwise.

     1.6  DEFINITIONS.  All references in this Agreement to financial
statements, assets, liabilities, profits and losses and similar accounting items
with respect to the Company shall mean such items prepared or determined using
the accrual method of accounting and the application of generally accepted
accounting principles as from time to time in effect in the United States.

     For purposes of this Agreement, the following shall have the meanings set
forth respectively after each:

          "ACCOUNTING PERIOD" shall mean the Fiscal Year; provided, however,
that an interim closing of the books of the Company shall take place if, within
an Accounting Period, additional capital is contributed to or amounts are
distributed by or withdrawn from the Company, if such contribution, distribution
or withdrawal results in a change in the allocation of subsequent profits,
losses, contributions or distributions.

          "AFFILIATES" of Chiron shall mean all corporations, or other entities,
more than 50% of whose shares or voting interests are owned, directly or
indirectly, by Chiron; "Affiliates" of Ciba shall mean Ciba Geigy Limited of
Basle Switzerland and all corporations, or entities, more than 50% of whose
shares or voting interests are owned, directly or indirectly, by Ciba-Geigy
Limited.

          "CAPITAL ACCOUNT" of a Member shall mean the separate Capital Account
maintained in accordance with Article 5.

          "CAPITAL CONTRIBUTION" of a Member shall mean the assets or property
contributed to the Company by or on behalf of any member as consideration for a
Membership Interest.  For the purposes of this Agreement, the value of property
contributed shall be deemed equal to each member"s share of the maximum Net
Purchased Amount under Section 2.3.2.

          "CODE" shall mean the Internal Revenue Code of 1986, as amended.

          "FISCAL YEAR" shall mean the 52 or 53 week period beginning on the
Monday closest to January 1 and ending on the Sunday closest to December 31 of
each year, or as otherwise required by law.

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          "MEMBERSHIP INTEREST" shall mean the rights of a Member in
distributions (liquidating or otherwise) and allocations of the profits, losses,
gains, deductions and credits of the Company.

          "NET INCOME OR NET LOSS" shall mean for any Fiscal Year the amount
computed as of the last day thereof of the net income or loss computed under
generally accepted accounting principles.

          "PERCENTAGE INTEREST" shall mean with respect to any Member, a
fraction (expressed as a percentage), the numerator of which is the total of the
Member's Capital Contribution and the denominator of which is the total of all
Capital Contributions of all Members.

          "TREASURY REGULATIONS" means regulations issued by the U.S. Treasury
Department pursuant to the Code.


                                       II
           CONTRIBUTIONS TO CAPITAL; TRANSFERS OF MEMBERSHIP INTEREST

     2.1  INITIAL CONTRIBUTIONS AND TRANSFERS.  As of the execution date of this
Agreement, the following have occurred:

          2.1.1     INITIAL CONTRIBUTION BY CHIRON AND ITS AFFILIATES.  Chiron
and its Affiliates have  first made the following contribution to capital in
return for 100% of the Membership Interests in the Company.  The portion of such
Membership Interests held by each of Chiron and its Affiliates is set forth in
Exhibit A.  Such 100% of Membership Interests consists of 250,000 units of
Membership Interest, each referred to herein from time to time as a "Unit".
Chiron and its Affiliates have contributed the following:

          (a)  CASH.  Cash in the amount of $2500.00.

          (b)  ROYALTY.  A royalty agreement in the form of Exhibit B (the
       "Royalty Agreement") with respect to royalties on certain specified
       products (the "Products") arising from Funded Projects, as defined in
       Section 2.3.4.

          (c)  CO-PROMOTION OPTION.  The option to co-promote all of those
       Products identified as "Adult Vaccines" on Schedule A of the Royalty
       Agreement (the "Adult Vaccines") in all countries of the world other
       than North America and Europe in which the Company, directly or
       indirectly, through Ciba or otherwise, reasonably has the field sales
       force and other promotional infrastructure necessary to successfully
       promote the Adult Vaccines.  In determining such adequacy, the
       capabilities of Ciba's sales force and promotional infrastructure or
       the sales force and promotional infrastructure of any Ciba Affiliate
       shall be deemed to be the field sales force and promotional
       infrastructure of the

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          Company, in all countries where Ciba elects to undertake co-promotion
          activities.  The option to co-promote shall not apply to any Products
          other than Adult Vaccines.  Such option shall be exercisable by the
          Company, on a country by country basis, by written notice to Chiron,
          at any time until 180 days following the granting of the first
          regulatory approval in North America or Europe to market and sell the
          first Adult Vaccine for which such regulatory approval is obtained.
          This option shall terminate automatically as to all Adult Vaccines, in
          any country, with respect to which the option is not exercised by the
          Company within the time limit set forth above, it being understood
          that it may be in the interests of the parties to explore, without
          obligation, a broadening and/or extension of such co-promotion.

               (i)  Upon exercise of the option by the Company, the parties
          shall negotiate in good faith a co-promotion agreement for the
          Adult Vaccines in the countries as to which the Company has
          exercised its co-promotion option, on commercially reasonable
          terms, which shall include (A) a pre-tax  co-promotion profit to
          the Company of not less than [CONFIDENTIAL TREATMENT REQUESTED] of 
          Net Sales of Adult Vaccines in such countries, (B) an obligation of 
          reasonable diligence, (C) a reservation in favor of Chiron of the 
          right to market to international public organizations such as UNICEF 
          and W.H.O., with an appropriate compensation to be paid to the Company
          for any co-promotional activity agreed to be provided by the Company
          supporting such international sales, and (D) such other terms as
          the parties may then agree.  The co-promotion right shall expire
          as to each Adult Vaccine six (6) years after the first commercial
          sale, on a country by country and product by product basis.

               (ii)  The Company agrees to exercise such option only in the
          event that the Company is able to contract with Ciba (or other
          entity acceptable to Ciba and Chiron) to perform the co-promotion
          activities.

               (iii)  The Company, and in the event that the Company has granted
          co-promotion rights hereunder to Ciba, the Company and Ciba shall
          keep accurate books and records as to its co-promotion, which
          books and records shall be subject to audit by Chiron, in the
          same manner as set forth in Section 3.05.

               (iv)  All obligations and rights of Ciba under this Section
          2.1.1(c) may be assigned to and performed by any of Ciba's
          Affiliates.

          2.1.2     INITIAL TRANSFER OF MEMBERSHIP INTEREST TO CIBA.  Chiron
and/or its Affiliates have transferred to Ciba 12,000 Units of Membership
Interest in the Company in consideration of U.S. $12,000,000.

     2.2  FURTHER CONTRIBUTIONS AND CREATION OF ADDITIONAL MEMBERSHIP INTEREST.
At any time, upon request of Chiron, and subject to the approval of Ciba
pursuant to Section 2.3.4,

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Chiron, directly or through its wholly owned affiliates, shall have the right to
receive additional Membership Interest in the Company, subject to a maximum of
300,000 aggregate Units of  Membership Interest in the Company held by all
Members, in return for additional contributions of capital to the Company as
follows:

          (a)  CASH.   Cash in an amount equal to the One Cent ($0.01) per Unit.

          (b)  PRODUCT RIGHTS.   Chiron shall grant to the Company the right to
      participate in commercial opportunities with respect to additional
      products other than the Products, based on one or more of the
      following structures, to be determined at Chiron"s election, but
      subject to approval by Ciba:

               (i) ROYALTY INTEREST.  Chiron may grant to the Company the right
          to receive a royalty on net sales of such products, subject to
          acceptable terms and conditions, such as those set forth in the
          Royalty Agreement.

               (ii)  MARKETING OR PROMOTION RIGHTS.  Chiron may grant to the
          Company the right to participate in the marketing and/or selling in
          selected markets of the identified product(s).  In such event, the
          parties would agree upon a supply arrangement under which Chiron would
          manufacture the products for sale through the Company or upon co-
          promotion arrangements under which the Company would market products
          sold through Chiron.  Such rights would be subject to acceptable terms
          and conditions, such as stated in Section 2.1.1(c) above.

               (iii)  PROFITS INTEREST.  Chiron may grant to the Company the
          right to receive a stated percentage of pre-tax profits and losses
          from the sale of products developed, manufactured and marketed by
          Chiron arising from the contributed project or products subject to
          acceptable terms and conditions.

     2.3  SALE OF MEMBERSHIP INTEREST TO CIBA.

          2.3.1     CIBA OBLIGATION.    From time to time at Chiron's request,
subject to the limitations set forth in this Section 2.3, during the period
commencing with the date hereof (the "Effective Date") and ending on December
31, 1999 (such period referred to herein as the "Funding Period"), Ciba agrees
to purchase and Chiron, or its Affiliate, agrees to sell to Ciba Units of
Membership Interest in the Company at a price of One Thousand Dollars ($1000.00)
per Unit.

          2.3.2     AGGREGATE PURCHASE LIMITATIONS.  Ciba's obligation to
purchase Units hereunder shall be subject to the following limitations:

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               (a)  The Net Purchased Amount, as defined below, shall not exceed
          Two Hundred Fifty Million Dollars (U.S. $250,000,000); provided,
          however, that such amount may be increased, at Chiron's request, to a
          maximum of Three Hundred Million Dollars (U.S. $300,000,000) pursuant
          to the Section 5.12 of the 1994 Investment Agreement.  "Net Purchased
          Amount" shall mean, at any time, the aggregate amount paid to Chiron
          or its Affiliates by Ciba for the purchase of Units pursuant to this
          Agreement, which shall include the $12,000,000 received by Chiron in
          return for the initial transfer of Units to Ciba hereunder.  The Net
          Purchased Amount will be reduced by the aggregate amount of any
          dividends or other capital distributions actually paid by the Company
          to Ciba and any profits to Ciba from co-promotion or marketing
          activity by Ciba pursuant to Section 2.1.1(c), in each case, through
          the date of any required purchase of Units.

               (b)  The Net Purchased Amount shall not exceed at any time one
          hundred percent (100%) of the R&D Costs, as defined below, incurred
          during the Funding Period  by Chiron and its Affiliates (including
          without limitation Chiron Biocine Company and Biocine S.p.A.)
          initially with respect to all subunit vaccines and traditional
          vaccines and with respect to IGF-1 (collectively, the "Funded
          Projects").  In the event that additional Funded Projects are added
          pursuant to Sections 2.1.4 and 2.3.4, R&D Costs associated with such
          projects shall be added to the preceding sentence.  As used herein,
          the "R&D Costs" for a given period shall mean the fully burdened,
          fairly allocated costs of Chiron, on a consolidated basis, of
          research, development, and regulatory approval activities with respect
          to Funded Projects, as determined under Chiron's normal project
          accounting practices, including reasonable and customary allocations
          of indirect and overhead expenses and charges in the nature of
          depreciation and amortization of capitalized cost, general and
          administrative expenses, and out-of-pocket expenses, to the extent
          that any of the foregoing were or are incurred on or after January 1,
          1995.  R&D Costs shall include Chiron's share of expenses of  R& D
          Costs of joint businesses with respect to Funded Projects.

          2.3.3     TIMING LIMITATIONS. In no event shall Ciba be obligated to
purchase Units such that the purchase price paid exceeds

          a)   Thirty-four Million Dollars (U.S. $34,000,000) in 1995;

          b)   In 1996, One Hundred Sixteen Million Dollars (U.S. $116,000,000),
             plus any unused portion of the funding limit for 1995 pursuant to
             section 2.3.3(a); and

          c)   For subsequent calendar years, equal annual portions of the
             remaining unexpended aggregate amount under Section 2.3.2 above.

          2.3.4     FUNDED PROJECTS.   Chiron agrees to use the proceeds of
sales of Units to Ciba hereunder solely for the purpose of research, 
development and regulatory approval

                                        6

<PAGE>

          activities with respect to Funded Projects, determined in accordance
          with this Section 2.3.4.
               (a)  In conjunction with any request by Chiron for the issuance
          of additional Units pursuant to Section 2.2, Chiron shall provide to
          Ciba proposals for research and development programs which Chiron
          desires to fund or partially fund as Funded Projects through the sale
          of such additional Units to Ciba.  No limitation shall be placed upon
          the number of Funded Projects that Chiron may present to Ciba during
          the Funding Period.

               (b)   Upon acceptance by Ciba of a proposal pursuant to Section
          2.3.4(a), the Company shall be authorized to issue additional Units
          pursuant to Section 2.2, and the proposed project shall become a
          Funded Project.  A Funded Project shall remain a Funded Project for
          purposes of this Agreement unless or until  Chiron elects, in its sole
          discretion, to discontinue research and development with respect to
          such project.  Chiron will manage the research with respect to Funded
          Projects in its sole discretion.

               (c)  Chiron will prepare, in consultation with Ciba,  annual and
          quarterly forecasts of the R&D Costs for each Funded Project.

          2.3.5     SALES OF UNITS.  From time to time, not more frequently than
once per fiscal quarter and prior to the conclusion of the fiscal quarter,
Chiron shall provide Ciba with a written notice of the amount of Units that it
or its Affiliates wish to sell to Ciba, and the associated purchase price, all
in accordance with the provisions of this Article 2.  Such purchase price shall
not exceed the lesser of  (i) 100% of R&D Costs of the Funded Projects incurred
on or after January 1, 1995 and not previously funded through sales of Units
hereunder; or (ii) the maximum funding obligation of Ciba pursuant to Section
2.3.3 for the period  in question.  Ciba shall purchase the requested amount of
Units, by paying the purchase price in U.S. dollars in immediately available
funds, by wire transfer, unless otherwise mutually agreed.  The purchase price
shall be due and payable within thirty (30) days following the notice delivered
by Chiron to Ciba pursuant to this Section 2.3.5.

          2.3.6     NO OTHER TRANSFER OF MEMBERSHIP INTEREST.   Chiron, its
Affiliates and Ciba agree that none of them shall transfer any Membership
Interest in the Company, nor shall the Company issue any new Membership
Interest, to any third party without the prior written consent of both Chiron
and Ciba; except that Ciba may transfer its Membership Interest, or cause future
Membership Interests to be purchased by, Ciba"s parent corporation or any wholly
owned subsidiary of Ciba"s parent corporation. Chiron further agrees that it
will not assign or transfer to a third party a controlling interest in any
Chiron Affiliate which is also a Member of the Company without the prior written
consent of Ciba.

          2.3.7  RETAINED INTEREST BY CHIRON.  In order to assure that the
Company has two Members at all times, Chiron agrees to retain and not to sell to
Ciba pursuant to this Section 2.3 at least one Unit of Membership in the
Company.

                                        7

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                                   ARTICLE III
                    CHIRON RESEARCH AND DEVELOPMENT ACTIVITY

     3.1  DILIGENCE.  Chiron and its Affiliates shall use reasonable commercial
diligence to pursue and complete the research and to develop, test, gain
regulatory approval for, market and sell the Products. In the event that less
than 100% of the R & D Costs of a Funded Project is provided to Chiron
hereunder, Chiron nevertheless shall spend its own portion of such R & D Costs
in conducting activities related to the Funded Project.

     3.2.  ALLOCATION OF FUNDING.  Where a Funded Project includes more than one
product under development, and in the event that more than one Funded Project is
subject to funding hereunder, funds received by Chiron or its Affiliates through
sales of Units shall be allocated, among the Products within a Funded Project,
and among Funded Projects, in Chiron's sole discretion.

     3.3  NO WARRANTY OF SUCCESS.  CHIRON MAKES NO WARRANTIES OR GUARANTEES OF
ANY KIND THAT THE RESEARCH AND DEVELOPMENT ACTIVITIES FUNDED  HEREUNDER WILL BE
SUCCESSFUL OR WILL ACTUALLY RESULT IN ANY PRODUCTS BEING MARKETED OR SOLD.

     3.4  RIGHTS TO INVENTIONS.  Nothing in this Agreement will cause Ciba or
the Company to obtain any ownership or license rights in any patent or other
intellectual property rights of Chiron in connection with any Funded Project; or
any other right or license not specifically granted herein or in the Royalty
Agreement.  Chiron will own the right, title and interest in and to any new
inventions arising in the course of any Funded Project, to the extent such
inventions are made by Chiron, its employees, agents or assignors.

     3.5  AUDIT RIGHTS.  Chiron and its Affiliates agree to keep accurate books
and records of the funding received through sales of Units hereunder, and the R
& D Costs incurred with respect to Funded Projects.  Ciba shall have the right,
at its own expense, for a period of three (3) years after the end of the Funding
Period, to have an independent certified public accountant ("CPA") reasonably
acceptable to Chiron examine the relevant books and records of Chiron and its
Affiliates, during normal business hours, at the principal offices of Chiron,
upon two (2) weeks advance written request, to verify the R & D Costs; provided,
however, that such audits shall not occur more than once per year.  Said CPA
shall be under confidentiality obligations to Chiron, to reveal  only whether
there is an error in the R & D Costs reported to Ciba, and if so, the amount of
such error.

                                        8

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                                   ARTICLE IV
                        REPURCHASE OF MEMBERSHIP INTEREST

     4.1  RIGHT TO REPURCHASE UNITS.  Chiron and/or its Affiliates shall have
the right (the "Buy-Out Right") to repurchase from Ciba all Units sold to Ciba
under this Agreement upon tender by Chiron to Ciba of payment in the amount of
the Buyout Amount (as hereinafter defined) in effect at the time of such tender;
provided that such right shall expire if such tender is not made prior to
January 1, 2002.

     As used herein, "Buyout Amount" shall mean an amount equal to (i) the sum
of all Unit purchase payments made by Ciba prior to the date of such tender
pursuant to this Agreement, PLUS (ii) interest thereon from the date of payment
until the date of such tender at a rate equal to LIBOR determined and compounded
on a quarterly basis,  LESS (iii)  the aggregate amount of any dividends or
other capital distributions received or receivable by Ciba from the Company and
any pre-tax profits received by Ciba from co-promotion or marketing activity by
Ciba pursuant to Section 2.1.1(c), to the date of such tender, which exceed the
pre-tax profits which would ordinarily be payable to a third party conducting
such co-promotion or marketing activity, LESS (iv) interest on the amounts
referenced in (iii) above from the date of actual receipt of such amount by Ciba
until the date of such tender at a rate equal to LIBOR determined and compounded
on a quarterly basis.  For the purposes of this Agreement, "LIBOR" means, with
respect to any calendar quarter, the three month U.S. Dollar rate as quoted by
the British Bankers Association (Bloomberg page "BBA", Telerate page "3767") as
of 11:00 a.m., London time, on the day that is two London banking days prior to
the commencement of such calendar quarter.

     4.2  FORM OF PAYMENT.    Chiron shall be entitled to make the payment of
the Buyout Amount in the form of cash, in immediately available funds, or Chiron
Common Stock ("Chiron Stock"), or a combination of the two.  If Chiron shall
elect to employ Chiron Stock for the purposes of making such payment, such
Chiron Stock shall be valued at its Fair Market Value as of the date immediately
preceding the date on which such payment shall be made.  As used herein, "Fair
Market Value" shall mean, as of any date of determination, the average of the
closing sale prices of Chiron Stock during the 10 trading day period immediately
preceding such date of determination on the principal United States securities
exchange registered under the Exchange Act on which Chiron Stock is listed, or,
if Chiron Stock is not listed on any such exchange, the average of the closing
sale prices or the closing bid quotations of the Chiron Stock during the 10
trading day period preceding such date of determination on the NASDAQ National
Market or any comparable system then in use, or, if no such quotations are
available, the fair market value of the Chiron Stock as of such date of
determination as determined in good  faith by a majority of the Independent
Directors,  as defined in that certain Governance Agreement among Ciba, Chiron
and Ciba-Geigy Corporation dated as of November 20, 1994.

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     4.3  EFFECT ON CO-PROMOTION RIGHT.  If, at the time of repurchase by Chiron
of Units pursuant to this Article 4, the Company has exercised the option to co-
promote the Adult Vaccines in one or more countries, pursuant to Section
2.1.1(c), and has contracted with Ciba to perform such obligations, Ciba shall
have the right to continue to co-promote Adult Vaccines then subject to said
right in such countries for the remainder of the term of such co-promotion
rights, all on the terms set forth in Section 2.1.1(c), or the right to expand
its co-promotion rights as provided in Section 4.4.

     4.4  RESIDUAL RIGHTS.   In the event that Chiron exercises its right to
repurchase all of the Units pursuant to this Article 4, Chiron agrees to grant
to Ciba the option (the "Residual Rights Option") to expand its marketing
rights, if any, with respect to all Adult Vaccines, as provided in this Section
4.04 (the "Residual Rights").  If exercised, Ciba would have the right to
convert its co-promotion right into the right to exclusively market and sell all
Adult Vaccines, in all countries of the world other than North America and
Europe, in which Ciba then has exercised its right to co-promote any Adult
Vaccine pursuant to Section 2.1.1(c) and to extend such exclusive marketing for
a period of six (6) years from the later of the date of Ciba's exercise of the
Residual Rights Option or the first approval for commercial sale, on a product
by product basis.

               (a)  The Residual Rights Option shall be exercisable by Ciba, by
          written notice to Chiron,  during the 60 days following Chiron's
          exercise of its Buy-out Right.  Upon exercise of the Residual Rights
          Option by Ciba, the parties shall negotiate in good faith an agreement
          under which Chiron would manufacture and supply, and Ciba would
          market, sell and distribute, the Adult Vaccines in the countries as to
          which Ciba has Residual Rights, all on commercially reasonable terms,
          including reasonable and customary distributor obligations to use
          diligence and to pursue and pay the cost of regulatory approvals and
          other marketing, selling and product introduction activities.

               (b)  Such agreement shall provide for a pre-tax distributor
          profit to Ciba of not less than [CONFIDENTIAL TREATMENT REQUESTED] 
          of Net Sales by Ciba of Adult Vaccines in such countries.  In the 
          event that the Net Purchased Amount, as defined in Section 2.3.2 is 
          less than $250,000,000, such minimum pre-tax distribution profit 
          payable to Ciba hereunder will be reduced by multiplying 
          [CONFIDENTIAL TREATMENT REQUESTED] of net 
          sales by the following fraction:

                         Net Purchased Amount
                         --------------------
                        $250,000,000

               (c)  Ciba's exclusive rights pursuant to this Section 4.4 shall
          be subject to the continuation of such promotional and sales activity
          as Chiron may be  permitted to conduct under any applicable co-
          promotion and other marketing agreements entered into between Chiron
          and the Company or Ciba prior to the exercise of Chiron's Buy-Out
          Right and to the negotiation of equitable and reasonable terms for (i)
          the phase out of such activity by Chiron after the expiration of the
          original terms of such agreements and (ii)

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<PAGE>

          compensating Ciba for the reduction of such exclusivity by reason of
          Chiron's continued activity.


     4.5  COOPERATION.  Chiron and Ciba shall meet and confer from time to time
to consider whether and to what extent it is in their respective best interests
to permit Chiron or any third party to participate in the marketing of Adult
Vaccines on a country by country basis.  Nothing in this Section 4.5, however,
shall obligate the Company or Ciba either (i) to exercise the options to acquire
co-promotion rights or Residual Rights or (ii) if Ciba exercises the option to
acquire the Residual Rights, to alter the Residual Rights as set forth in
Section 4.4, except to the extent that Ciba determines it to be in its best
interest to do so in the reasonable exercise of its discretion.


                                    ARTICLE V
                                CAPITAL ACCOUNTS

     CAPITAL ACCOUNTS.  The Company shall establish and maintain an individual
Capital Account for each of the Members in accordance with Treasury Regulation
1.704-1(b)(2)(iv).


                                   ARTICLE VI
                               MEETINGS OF MEMBERS

     6.1  PLACE OF MEETINGS.  All meetings of Members shall be held at the
principal place of business of the Company or at such other place as may be
designated from time to time by the Members.

     6.2  ANNUAL MEETING.  An annual meeting of Members for the election of the
Board of Directors and for the transaction of such other business as may
properly be brought before the meeting shall be held on such date designated by
the Board of Directors but not less frequently than once each fiscal year.

     6.3  SPECIAL MEETINGS.  Special meetings of Members may be called at any
time by the Members or by any Member upon written request.

     6.4  QUORUM.  A quorum shall be present at a meeting of Members only if
Chiron and Ciba are present in person or represented by proxy.

     6.5  VOTING AND PROXIES.  Each Member shall have a number of votes equal to
the number of Units of Membership Interest held by it.

     However, the Members hereby agree that:

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          (i)    the Company shall not enter into any agreements or conduct any
               transactions, other than those specifically authorized in this
               Agreement or the Royalty Agreement, without the approval of both
               Chiron and Ciba.

          (ii)   Ciba shall have the right to require that the Company exercise
               its rights under this Agreement, including without limitation 
               the co-promotion option, and under the Royalty Agreement. Each 
               of Chiron and Ciba shall be authorized to enforce against the 
               other any and all rights of the Company against such other 
               party.

     6.6  ACTION WITHOUT MEETING.  Any action required or permitted to be taken
at any annual or special meeting of Members of the Company may be taken without
a meeting, without prior notice and without a vote, if a consent in writing,
setting forth the action so taken, is signed by all Members.

     6.7  PARTICIPATION BY TELEPHONE.  Members may participate in a meeting
through use of conference telephone or similar communications equipment, so long
as all Members participating in such meeting can hear one another.


                                   ARTICLE VII
                                   MANAGEMENT

     7.1  BOARD OF DIRECTORS.

             (a) AUTHORITY OF THE BOARD OF DIRECTORS.  Subject to Section 6.5
and except for situations in which the approval of the Members is required by
this Agreement or by applicable law, the day-to-day management of the business
and affairs of the Company shall be vested in the Board of Directors, which
power and authority shall be subject to delegation by the Board of Directors to
the officers and other agents of the Company in the manner provided herein.

             (b) ELECTION OF BOARD OF DIRECTORS.  The Board of Directors shall
consist of three members, two of which shall be appointed by the Member holding
the majority of Units of Membership Interest, with the remaining Director
appointed by the other Member.  Unless otherwise agreed by the Members, one
Director appointed by each Member will have appropriate scientific background.
For this purpose, Chiron shall be deemed to hold the Units held by its
Affiliates.

                 The initial Directors will be William Green and Dennis Winger;
provided that as soon as practicable following the execution of this Agreement,
Chiron and Ciba shall elect directors in accordance with the preceding
paragraph.

                                       12

<PAGE>

                 Thereafter, the members of the Board of Directors shall be
elected at the annual meeting of Members and shall hold office until their
successors have been elected and qualified, or until their death, resignation or
removal, in accordance with this Section 7.1.

             (c) VACANCIES; REMOVAL; RESIGNATION.  Any vacancy occurring on the
Board of Directors may be filled by the party who shall have initially elected
the Director whose position shall have become vacant.  A Director elected to
fill a vacancy shall be elected for the unexpired term of his or her predecessor
in office.  A Director may be removed and a new Director elected by the written
action of only the Member who initially elected the Director to be removed,
pursuant to Section 7.1(b) above.  Any Director may resign at any time.

     7.2     CHANGE IN HOLDER OF MAJORITY OF UNITS.    In the event that Ciba
acquires a majority interest in the Company, the parties agree to hold a Members
meeting within thirty (30) days following the date on which such majority
interest is acquired.  At such meeting, new Directors shall be elected pursuant
to Section 7.1, and new officers shall be appointed pursuant to Section 7.3.


     7.3     OFFICERS.

            (a)     APPOINTMENT.  Unless otherwise agreed, the Company shall
have three officers, with the President and one other officer appointed by the
Directors designated by the holder of a majority of Units, and the remaining
officer appointed by the Directors designated by the other Member.

                    The initial officers of the Company shall be Dennis Winger,
President, and William Green, Secretary; provided that as soon as practicable
following execution of this Agreement, the Directors designated by Ciba shall
appoint a third officer of the Company.

             (b)    AUTHORITY.  Any officers so designated shall have such
authority and perform such duties as the Board of Directors may, from time to
time, delegate to them.  Unless the Members decide otherwise, if the title is
one commonly used for officers of a business corporation formed under the
Delaware General Corporation Law, the assignment of such title shall constitute
the delegation to such officer of the authority and duties that are normally
associated with that office, subject to any specific delegation of authority and
duties made to such officer by the Members or the Board of Directors.  Each
officer shall hold office until his or her successor shall be duly designated
and shall qualify or until his death or until he shall resign or shall have been
removed in the manner hereinafter provided.  Any number of offices may be held
by the same person.

             (c)    VACANCIES; REMOVAL; RESIGNATION.  Any officer may resign as
such at any time.  Such resignation shall be made in writing and shall take
effect at the time specified therein, or if

                                       13

<PAGE>

no time be specified, at the time of its receipt by the Board of Directors.  The
acceptance of a resignation shall not be necessary to make it effective, unless
expressly so provided in the resignation.  Any officer may be removed as such,
either with or without cause, by the Directors who appointed such officer.  Any
vacancy occurring in any office of the Company may be filled by the Directors
who had the authority to elect the officer holding such position.

     7.4  STANDARD OF CARE.

          (a)  It is understood that the business of the Company involves a
degree of risk.  The Board of Directors shall not be liable, responsible or
accountable in damages or otherwise to any Member for, and the Company shall
indemnify and save harmless the Board of Directors from and against, any loss or
damage incurred by reason of any act or omission performed or omitted by it in
good faith on behalf of the Company and in a manner reasonably believed by it to
be within the scope of the authority granted to it by this Agreement, provided
that the Board of Directors was not guilty of gross negligence or willful
misconduct with respect to such act or omission.  Any act or omission performed
or omitted by the Board of Directors in good faith on advice of counsel,
accountants and other independent experts to the Company shall be conclusively
deemed to have been performed or omitted by the Board of Directors in good
faith.

          (b)  The Board of Directors acting in good faith, may rely upon, and
shall be protected in acting or refraining from acting upon, any resolution,
certificate, statement, instrument, opinion, report, notice, request, consent,
order, bond, debenture or other paper or document believed by it to be genuine
and to have been signed or presented by the proper party or parties.

                                  ARTICLE VIII
                             ACCOUNTING AND RECORDS

     8.1  FINANCIAL AND TAX REPORTING.  The Company shall prepare its financial
statements in accordance with generally accepted accounting principles as from
time to time in effect using the accrual method of accounting on a Fiscal Year
basis, and shall prepare its income tax information returns on a Fiscal Year
basis, using the method of accounting required under the Code and Treasury
Regulations or when one or more alternative methods are available, using the
method of accounting which the Board of Directors deems appropriate.

     8.2  SUPERVISION; INSPECTION OF BOOKS.  Proper and complete books of
account and records of the business of the Company shall be kept under the
supervision of the Board of Directors at the Company's principal office or at
such other place as designated by the Board of Directors.  Such books and
records shall be open to inspection, audit and copying by any Member, or its
designated representative, upon reasonable notice at any time during business
hours for any purpose reasonably related to the Member's interest in the
Company.  Any


                                       14

<PAGE>

information so obtained or copied shall be kept and maintained in strictest
confidence except as required by law.

     8.3  RELIANCE ON RECORDS AND BOOKS OF ACCOUNT.  Any Member shall be fully
protected in relying in good faith upon the records and books of account of the
Company and upon such information, opinions, reports or statements presented to
the Company by its Board of Directors, any of its other Members, officers, or by
any other person, as to matters the Member reasonably believes are within such
other person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Company, including information, opinions,
reports or statements as to the value and amount of the assets, liabilities,
profits or losses of the Company or any other facts pertinent to the existence
and amount of assets from which distributions to Members might properly be paid.

     8.4  TAX RETURNS.  The Member who is named the "tax matters partner"
pursuant to Section 9.3(f) shall, on or before the due date prescribed by law
(including any extensions of time), file a federal income tax information return
and transmit to each Member a schedule showing such Member's distributive share
of the Company's taxable income, deductions and credits, and all other
information necessary for such members timely to file their Federal income tax
returns.  Such Member similarly shall file all appropriate state and local
income tax returns or information returns on behalf of the Company.  The Board
of Directors shall, from time to time as appropriate under Section 6654 of the
Code, provide to the Members interim financial information regarding the Company
so that the Members and/or the direct or indirect equity holders of any Member
may timely determine their quarterly federal estimated tax obligations.


                                   ARTICLE IX
                                   ALLOCATIONS

     9.1  ALLOCATION OF NET INCOME OR NET LOSS.

          (a)  For each Accounting Period, Net Loss shall be allocated as
follows:

                  (i)  First, to the extent that the Capital Account of any
Member (determined after giving effect to adjustments attributable to any
contributions made or distributions received during that Accounting Period)
exceeds the amount of distribution to which such Member would be entitled to
receive under Section 13.4 were the Company to be dissolved and its assets
distributed in liquidation, then to each Member having such excess in proportion
to such excess;

                  (ii)  Second, any remaining Net Loss shall be allocated to
Members in proportion to their Percentage Interests.

                                       15

<PAGE>

          (b)  For each Accounting Period, Net Income shall be allocated as
follows:

               (i)   First to the extent that the Capital Account of any Member
(determined after giving effect to adjustments attributable to any contributions
made or distributions received during that Accounting Period) is less than the
amount of distribution to which such Member would be entitled under Section 13.4
were the Company to be dissolved and its assets distributed in liquidation, then
Net Income shall be allocated to each Member having a shortfall in the
proportion to such shortfall;

               (ii)  Second, any remaining Net Income shall be allocated to
Members in proportion to their Percentage Interests.

     9.2  TIME OF ALLOCATIONS.  The Net Income or Net Loss of the Company for
each Accounting Period shall be allocated to the Members' Capital Accounts
during the Accounting Period in accordance with the provisions of this Article
IX.

     9.3  SPECIAL TAX PROVISIONS.

          (a)  TAX ALLOCATIONS.  Except as otherwise provided in this
Article IX, items of Company income, gain, loss or deduction recognized for
income tax purposes shall be allocated in the same manner that the corresponding
items entering into the calculation of Net Income and Net Loss are allocated
pursuant to this Agreement.

          (b)  SECTION 704(c) ADJUSTMENTS.  In accordance with Code Section
704(c) and the Treasury Regulations thereunder, items of income, gain, loss and
deduction with respect to an asset, if any, contributed to the capital of the
Company shall, solely for tax purposes, be allocated between the Members so as
to take account of any variation between the adjusted basis of such property to
the Company for Federal income tax purposes and its fair value upon contribution
to the Company.  Upon a revaluation of the Members' Capital Accounts under this
Agreement to reflect unrealized gain or loss accruing during any Accounting
Period, subsequent allocations of items of income, gain, loss and deduction for
tax purposes shall be adjusted to take account of any variation between the
adjusted tax basis and the adjusted value of the Company's assets in accordance
with the principles of Code Section 704(c) and subparagraph (d) and (g) of
Treasury Regulation Section 1.704-1(b)(2)(iv).

          (c)  OTHER.  The allocations provided herein shall be subject to the
following exceptions:

               (i)  LIMITATIONS OF LOSSES.  A Member's Capital Account shall not
be allocated any item of Net Loss to the extent such allocation would cause such
Capital Account to have a negative balance (computed in accordance with the
principles of Treasury Regulation Section 1.704-1(b)(2)(ii)(d)) in excess of any
amount such Member is obligated to restore (or

                                       16

<PAGE>

deemed to be obligated to restore under Treasury Regulation Section 1.704-
1(b)(2)) to the Company.

               (ii)  QUALIFIED INCOME OFFSET.  If any Member unexpectedly
receives any adjustments, allocations or distributions which would cause its
Capital Account to have a negative balance (computed with such adjustments as
are required under the Treasury Regulations) in excess of any amount such Member
is obligated to restore (or deemed to be obligated to restore under Treasury
Regulation Section 1.704-1(b)(2)) to the Company, then special allocations of
Net Income (and items thereof), together with corresponding tax items, shall be
made as quickly as possible so as to comply with the "qualified income offset"
provisions of Treasury Regulation Section 1.704-1(b)(2)(ii)(d).

               (iii) SUBSEQUENT ALLOCATIONS.  Any special allocations pursuant
to the foregoing provisions of this subsection (c) shall be taken into account
as soon as possible in computing subsequent allocations of Net Income or Net
Loss (and items thereof), together with corresponding tax items, so that over
the term of the Company the aggregate amount of any Net Income or Net Loss
allocated to each Member shall, to the extent possible, be equal to the
aggregate amount that would have been allocated to each such Member if the
allocations pursuant to the foregoing provisions of this subsection (c) had not
occurred.

             (d) SECTION 754 ELECTION.  A Section 754 election shall be made for
the Company.  In the event of an adjustment to the adjusted tax basis of any
Company asset under Code Section 734(b) or Code Section 743(b) pursuant to a
Section 754 election by the Company, subsequent allocations of tax items shall
reflect such adjustment consistent with the Treasury Regulations promulgated
under Sections 704, 734 and 743 of the Code.

             (e) ALLOCATIONS UPON TRANSFERS OF COMPANY INTERESTS.  If, during an
Accounting Period, a Member (the "Transferring Member") transfers all or part
of its interest in the Company to another Member, items of Net Income and Net
Loss, together with corresponding tax items, that otherwise would have been
allocated to the Transferring Member with regard to such Accounting Period shall
be allocated between the Transferring Member and the other Member in accordance
with their respective interests in the Company during the Accounting Period
using any method permitted by Section 706 of the Code and selected by the Board
of Directors.

             (f) TAX MATTERS PARTNER.  The " tax matters partner" of the Company
within the meaning of Section 6231(a)(7) of the Code shall be Chiron, provided
Ciba shall have the right, upon notice to Chiron, to become the "tax matters
partner", for any year in which as of the beginning of such year it held a
majority of the Membership Units in the Company.  The tax matters partner shall
act for and on behalf of the Company to the extent required under Sections 6221
through 6233 of the Code and shall provide timely notification to the Members of
all proposed adjustments to, or administrative proceedings regarding, Company
tax items.

                                       17

<PAGE>

             (g) ADJUSTMENTS TO TAXABLE INCOME UPON EXAMINATION.  If upon
examination of any tax return an adjustment is made by any tax authority and
agreed to by the Company for any Accounting Period, such adjustment shall be
allocated among Members in accordance with the provisions of Section 9.1(a) and
(b). No such adjustment shall be agreed to by the Company, except with the
unanimous consent of the Unit holders.




                                    ARTICLE X
                                  DISTRIBUTIONS

     10.1 DISTRIBUTIONS AND WITHDRAWALS.  Distributions and withdrawals shall be
made as follows:

          (a)  DISTRIBUTION OF AVAILABLE CASH.  To the extent the Company's cash
on hand exceeds its current and anticipated needs, including, without
limitation, needs for operating expenses, debt service, acquisitions, reserves
and mandatory distributions, if any, including distributions in liquidation, the
Board of Directors, with the consent of all Members, may make distributions to
the Members pro rata in accordance with their respective Capital Account
balances.

          (b)  DISTRIBUTIONS IN KIND.

                  (i)  The Board of Directors, with the consent of all Members,
may elect to distribute any non-cash assets held by the Company in kind to the
Members pro rata in accordance with their respective Capital Account balances

                  (ii)  Any non-cash assets distributed in kind shall be subject
to such conditions and restrictions as are legally required or as are
contractually imposed on the Company and its successors.

                                       18

<PAGE>

          (c)  NO OTHER WITHDRAWALS.  Except as provided in this Section 10.1,
no withdrawals or distributions are permitted or required.

          (d)  EFFECT OF WITHHOLDING.  To the extent the Company reasonably
determines that it is required to withhold and pay any amount for local, state,
federal and/or foreign taxes with respect to any Member, the Company is hereby
expressly authorized to make such payment.  The amount of any such payment shall
be treated as an advance from the Company to the Member with respect to whom the
withholding and payment were required, and the Company is hereby expressly
authorized to collect repayment of such advance out of any and all distributions
which are then or may thereafter become payable to such Member.  This Section
10.1(d) shall not preclude the Company from pursuing any other remedy which may
be available.



                                   ARTICLE XI
                   INDEMNIFICATION AND LIMITATION OF LIABILITY

     11.1 INDEMNIFICATION WITH RESPECT TO MANAGEMENT OF THE COMPANY.

          (a)  The Company shall indemnify and hold harmless the Members, the
Board of Directors, officers, employees and agents of the Company, and the
partners, shareholders, controlling persons, officers, directors and employees
of any of the foregoing (herein referred to as "Indemnitees") from and against
any and all loss, claims, damages, liabilities joint and several, expenses,
judgments, fines, settlements and other amounts arising from any and all claims
(including reasonable legal expenses), demands, actions, suits or proceedings
(civil, criminal, administrative or investigative) in which they may be
involved, as a party or otherwise, by reason of their management of, or
involvement in, the affairs of the Company, or rendering of advice or
consultation with respect thereto, or which relate to the Company, its
properties, business or affairs; provided in all cases that in connection
therewith the Indemnitee shall have met the standard of care described for
members of the Board of Directors in Section 7.4 hereof.  Such indemnification
shall be to the fullest extent permitted by applicable law.

          (b)  Expenses (including attorneys' fees) incurred in defending any
proceeding under subsection (a) may be paid by the Company in advance of the
final disposition of such proceeding upon receipt of an undertaking by or on
behalf of the Indemnitee or Person to repay such amount if it shall ultimately
be determined that the Indemnitee or Person is not entitled to be indemnified by
the Company as authorized hereunder.

          (c)  The indemnification provided by this Section 11.1 shall not be
deemed to be exclusive of any other rights to which any person may be entitled
under any agreement, or as a matter of law, or otherwise, both as to action in a
person"s official capacity and to action in another capacity.

                                       19

<PAGE>


          (d)  If directed by the Members, the Board of Directors shall purchase
and maintain insurance on behalf of itself, the Company, the Members, officers,
employees or agents of the Company and any other Indemnitees at the expense of
the Company, against any liability asserted against or incurred by them in any
such capacity whether or not the Company would have the power to indemnify such
Persons against such liability under the provisions of this Agreement.

     11.2 LIMITATION OF LIABILITY.  Notwithstanding anything to the contrary
herein contained, the debts, obligations and liabilities of the Company shall be
solely the debts, obligations and liabilities of the Company; and no Member
shall be obligated personally for any such debt, obligation or liability of the
Company solely be reason of being a Member of the Company, except if otherwise
provided by the Act.

     11.3 INDEMNIFICATION REGARDING PRODUCTS ARISING FROM FUNDED PROJECTS.

     Chiron agrees to indemnify, defend and hold the Company and Ciba harmless
from and against any and all claims, losses, damages, liabilities, costs and
expenses (including reasonable attorneys' fees) (collectively, "Claims") arising
as a result of Chiron's research and development activities which are funded
pursuant to this Agreement, or as a result of the manufacture, use or sale of
any product arising from a Funded Project, except to the extent that such Claims
result from (i) marketing, sale or promotion of the product by the Company,
Ciba, or their respective affiliates or licensees, in deviation from the
approved labeling for the product in question, or (ii) negligence or willful
misconduct of the Company, Ciba, or their respective employees, agents or
consultants.  Ciba agrees to indemnify, defend and hold Chiron harmless from and
against Claims resulting from (i) or (ii) above.

     The party seeking indemnification hereunder ("indemnified party") agrees to
notify the other party (the "indemnifying party") promptly after receipt of
notice of any Claim, and to cooperate with the indemnifying party in connection
with the investigation and defense of any Claim. The indemnifying party shall
have the right to control such defense, using counsel selected by the
indemnifying party, provided that the indemnified party shall have the right to
participate in such defense through its own counsel, at its sole expense. The
indemnifying party shall have the sole right to control the settlement or
disposition of any such Claim, provided that the indemnifying party shall not
settle or compromise any Claim in any manner which would materially adversely
impact the rights or activities of the indemnified party without prior written
consent of the indemnified party, as the case may be, which consent shall not be
unreasonably withheld.

                                       20

<PAGE>

                                   ARTICLE XII
                                 CONFIDENTIALITY

     12.1 During the term of this Agreement and for a period of five (5) years
following the expiration or termination of this Agreement, the Company and Ciba
agree to maintain in confidence all confidential or proprietary information of
Chiron ("Confidential Information") which is disclosed to the Company or Ciba
pursuant to this Agreement.  The Company and Ciba shall use such Confidential
Information only as permitted by this Agreement and shall not disclose the same
to anyone other than its employees, agents or consultants, as are necessary for
the purposes of this Agreement.  Any such disclosure shall be on terms and
conditions at least as restrictive as those contained herein.

     12.2 The foregoing obligation of confidentiality shall not apply to the
extent that (a) the Company and Ciba are required to disclose information by
law, order or regulation of a governmental agency or a court of competent
jurisdiction, and provides Chiron with reasonable notice prior to such
disclosure, and cooperates with Chiron in seeking such protection for such
disclosed information as Chiron may determine; or  (b) the Company or Ciba can
demonstrate that:  (i)  the information was at the time of receipt already in
the public domain or thereafter entered the public domain other than as a result
of actions of the Company, Ciba, or any of their respective employees,
consultants, or agents, in violation hereof; (ii) the information was rightfully
known by the Company and Ciba prior to the date of receipt hereunder; or (iii)
the  information was disclosed to the Company or Ciba by a third party  source
not under a duty of confidentiality to Chiron; or (iv) the information was
independently developed by the Company or Ciba by employees, agents or
consultants who had no access to the Confidential Information.


                                  ARTICLE XIII
                                   TERMINATION

     13.1 TERMINATION.  The Company shall be dissolved, its assets disposed of
and its affairs wound up upon the first to occur of the following:

          (a)  upon the expiration of the 20-year period commencing with the
date of this Agreement;

          (b)  upon the agreement of Members holding at least 98% of all
Membership Interest; or

          (c)  upon the entry of a decree of judicial dissolution under the Act.

                                       21

<PAGE>

     13.2 EFFECT OF DISSOLUTION.  Upon dissolution, the Company shall cease
carrying on, as distinguished from winding up, its business, but the Company is
not terminated, and continues until the winding up of the affairs of the Company
is completed and a Certificate of Cancellation has been filed with the Delaware
Secretary of State.

     13.3 WINDING UP AND CERTIFICATE OF CANCELLATION.  The winding up of the
Company shall be completed when all debts, liabilities and obligations of the
Company have been paid and discharged or reasonably adequate provision therefor
has been made, and all of the remaining property and assets of the Company have
been distributed to the Members.  Upon the completion of winding up of the
Company, a Certificate of Cancellation shall be filed with the Delaware
Secretary of State.

     13.4 DISTRIBUTION OF ASSETS.  Upon dissolution and winding up of the
Company, the affairs of the Company shall be wound up and the Company liquidated
by the Board of Directors.  The assets of the Company shall be distributed as
follows in accordance with the Act:

          (a)  to creditors of the Company in the order of priority provided by
law;

          (b)  to Members for any amounts the Company owes them, other than in
respect of their interest in the Company capital and profits; and

          (c)  to the Members in accordance with Article X.



                                   ARTICLE XIV
                    ACTION BY CIBA MEMBERS OF CHIRON BOARD


          Ciba agrees that the members of the Chiron Board of Directors which
are designated by Ciba pursuant to that certain Governance Agreement dated as of
November 20, 1994, shall refrain from voting, or otherwise acting to direct or
control Chiron, with respect to any matter relating to the Funded Projects,
Chiron's ownership of Membership Interest in the Company, or Chiron's exercise
of its rights to repurchase Membership Interest in the Company hereunder.

                                   ARTICLE XV
                                  MISCELLANEOUS

     15.1 OBLIGATIONS UNDER OTHER AGREEMENTS.  The promotional and marketing
options hereunder are in lieu of the application of Sections 3.02 and 4.02 of
that certain Cooperation and Collaboration Agreement between Chiron and Ciba
dated as of November 20, 1994, with respect to all products arising from the
Funded Projects. All obligations in such Sections are suspended


                                       22

<PAGE>

during the term of this Agreement, the Royalty Agreement and any co-promotion or
marketing agreements hereunder with respect to the products covered hereby and
thereby.

     15.2 ASSIGNMENT.   Neither party shall have the right to assign any of its
rights or obligations hereunder to any unaffiliated third party without the
prior written consent of the other party hereto, which consent shall not be
unreasonably withheld.  Subject to the foregoing, this Agreement shall be
binding on, and inure to the benefit of, the parties, their successors and
permitted assigns.

     15.3 SEVERABILITY.    If any provision of this Agreement should be held
invalid or unenforceable, the remaining provisions hereof shall be unaffected
and shall remain in full force and effect without regard to such invalid or
unenforceable provisions, provided that such remainder is consistent with the
intent of the parties as evidenced by this Agreement as a whole.

     15.4 AMENDMENT.    This Agreement may not be modified or amended except in
writing signed by all Members.

     15.5 ENTIRE AGREEMENT.    This Agreement and the Amended and Restated
Royalty Agreement  represent the entire agreement of the parties with respect to
the subject matter hereof, and supersedes all prior negotiations and agreements,
including without limitation Exhibit B to the 1994 Investment Agreement, and the
Investment, Research Support and Marketing Agreement originally executed as of
September 29, 1995 together with the Royalty Agreement which constituted
Schedule 1.03 thereto and all other exhibits and schedules thereto.

     15.6 GOVERNING LAW.  This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware.

     15.7 COUNTERPARTS.  This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, and all of which
together shall constitute a single agreement.

     IN WITNESS WHEREOF, the parties hereto have executed this Company Agreement
as of the day and year first above written.

MEMBERS:


CHIRON CORPORATION

By:  William Rutter
     ---------------

Title: Chairman
      ---------

                                       23

<PAGE>

CHIRON BIOCINE COMPANY

By:  William Green
     -------------

Title: Secretary
       ---------


BIOCINE S.p.A.

By:  William Rutter    William Green
     --------------    -------------

Title: Director          Director
       --------          --------

CIBA-GEIGY CORPORATION

By:  John McGraw
    ------------
     John McGraw
Title:    Vice President


Exhibits: A    Initial Membership Interests of Chiron and its Affiliates
          B    Royalty Agreement

                                       24

<PAGE>

                                    EXHIBIT A

            INITIAL MEMBERSHIP INTERESTS OF CHIRON AND ITS AFFILIATES




[CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                                                Exhibit B


                                ROYALTY AGREEMENT



     This Amended and Restated Royalty Agreement is made effective as of
December 28, 1995, by and between Chiron Corporation ("Chiron"), a Delaware
corporation, Chiron Biocine Company and Biocine S.p.A., both wholly owned
Affiliates of Chiron, and Chiron Funding L.L.C., a Delaware Limited Liability
Company (the "Company"), and replaces and supersedes in full that certain
Royalty Agreement previously entered into by and among Chiron and Chiron Funding
Corporation as of September 29, 1995.

RECITALS.

     Chiron and its Affiliates and Ciba-Geigy Corporation ("Ciba"), a New York
corporation, have entered into a Limited Liability Company Agreement  of even
date herewith (the "LLC Agreement"), with respect to the formation and operation
of the Company.  The parties wish to set forth the terms under which Chiron will
pay to the Company royalties on certain products arising from the Funded
Projects, which products are identified on Schedule A hereto (the "Products"),
as contemplated in Section 2.1.1(b) of the LLC Agreement.

AGREEMENTS.

All capitalized terms not defined in this Agreement shall have the meanings set
forth in the LLC Agreement.

1.   ROYALTIES

     1.01   OBLIGATION TO PAY ROYALTIES.  In consideration of the Membership
     Interests in the Company issued to Chiron and its Affiliates pursuant to
     Section 2.1.1 of the LLC Agreement, and subject to the terms and conditions
     set forth herein, Chiron and its Affiliates hereby agree to pay to the
     Company royalties on the Products during the Royalty Term set forth in
     Section 3.  Such royalties for each Product shall be a percentage of
     worldwide Net Sales, as defined below, calculated as follows.

     1.02  BASE ROYALTY RATE FOR BASE NET SALES AMOUNT.  If total annualized
     worldwide Net Sales for all Products during a given year within the Royalty
     Term are less than or equal to the amounts shown on Schedule B hereto, the
     royalty rate shall be  [CONFIDENTIAL TREATMENT REQUESTED] of Net Sales
     (the "Base Royalty Rate").


                                        1
<PAGE>


     1.03  ROYALTY RATE FOR NET SALES IN EXCESS OF BASE NET SALES AMOUNT.  In
     the event that annualized Net Sales of all Products during any year of the
     Royalty Term exceed the amounts set forth in Schedule B, the Base Royalty
     Rate shall be reduced ratably, up to a maximum reduction of [CONFIDENTIAL 
     TREATMENT REQUESTED] in the event that annualized Net Sales are greater 
     than or equal to [CONFIDENTIAL TREATMENT REQUESTED] of the amounts shown 
     in Schedule B. For annualized Net Sales amounts between those set forth on
     Schedule B and [CONFIDENTIAL TREATMENT REQUESTED] of such amounts, the Base
     Royalty Rate shall be reduced based on the following formula:

     Royalty Rate =  [CONFIDENTIAL TREATMENT REQUESTED]

     For example, if actual annualized Net Sales in 2002 were greater than or
     equal to U.S. $2,022,000,000, the Royalty Rate would be

            [CONFIDENTIAL TREATMENT REQUESTED]

     However, if actual annualized Net Sales in 2002 were U.S.$1,617,600,000,
     the Royalty Rate would be

            [CONFIDENTIAL TREATMENT REQUESTED]

     1.04  ADJUSTMENT FOR LACK OF PATENT PROTECTION.  All royalties payable
     hereunder shall be reduced by [CONFIDENTIAL TREATMENT REQUESTED] with 
     respect to Net Sales in any country in which the sale of the Product in
     question is not covered by any patents or patent applications held by 
     Chiron or its Affiliates, whether due to the lack of patent applications,
     adjudicated invalidity of patents, or expiration of patents prior to the 
     end of the royalty term.

     1.05  "AFFILIATES."  As used herein, Affiliates of Chiron shall include all
     entities controlled by Chiron, but shall not include the Company and shall
     not include Ciba or any entity controlled by or under common control with
     Ciba which is not also controlled by Chiron.  Affiliates of Chiron
     specifically include Chiron Biocine Company and Biocine S.p.A.


22.  NET SALES.  As used herein, "Net Sales" means the invoiced price of a
product sold by Chiron, its Affiliates or licensees, less (i) discounts,
rebates, chargebacks and allowances; (ii) credits or refunds for returned or
damaged goods; (iii) sales, use, excise, value added and similar taxes; (iv)
customs, export and import duties and other governmental charges; (v)
transportation and insurance charges; (vi) royalties payable to third parties;
(vii) costs incurred by Chiron, including amounts payable in damages or
settlement, in defending claims by third parties that the products infringe
third party intellectual property rights.


                                        2
<PAGE>


     In the event that a Product is sold in combination with another active
ingredient, or with a delivery system not developed as part of the Product, or
with instrumentation, or with other components in a kit, or with services
related to the use of the product (all collectively referred to as "Other
Components", and the resulting product referred to as a "Combination Product"),
the parties shall reasonably determine the portion of Net Sales of the
Combination Product which should be allocated to the Product.  If the Product
and the Other Components are sold separately, the Net Sales for the purpose of
this Agreement shall be determined by multiplying the gross invoiced price of
the Combination Product, less the deductions specified above, by a the fraction
[CONFIDENTIAL TREATMENT REQUESTED], where [CONFIDENTIAL TREATMENT REQUESTED].  
If no such separate sales are made, the appropriate allocation shall be 
negotiated in good faith by the parties.

 3.  ROYALTY TERM. Royalties shall be payable hereunder with respect to Net
Sales of Products occurring on or after October 1, 2001.  Royalties shall
continue to be payable, on a Product by Product basis, with respect to Net Sales
occurring within ten years from the later of October 1, 2001 or the date of
first commercial sale of the Product in question.   If, at the end of the
Royalty Term, Ciba has not received, through its share of royalties paid to the
Company hereunder and its share of co-promotion profits pursuant to Section
2.11(c) of the LLC Agreement, an aggregate amount equal to the sum of all Unit
purchase payments made by Ciba pursuant to Section 2.3 of the LLC Agreement plus
interest thereon from the date of such payments at a rate equal to LIBOR, as
defined in Section 4.1 of the LLC Agreement,  then the Royalty Term shall be
extended until such time as Ciba has received such aggregate  amount.


4.   ROYALTY PAYMENTS AND REPORTS

     4.01.  PAYMENTS.  All royalties payable to the Company hereunder shall be
     paid in U.S. Dollars, on a quarterly  basis within ninety (90) days
     following the close of Chiron's fiscal quarter, with respect to Net Sales
     of Products during such fiscal quarter.

     4.02.  REPORTS.  Each royalty payment shall be accompanied by  a written
     report setting forth in reasonable detail the Net Sales of Products by
     Chiron, its affiliates and licensees during the applicable period and the
     resulting calculation of the royalty payment due hereunder.   For the
     purposes of determining royalties hereunder, Net Sales shall be calculated
     in the currency of the country of sale and then converted to U.S. Dollars
     in accordance with Chiron's standard accounting practices.

     4.03.  TAXES.  If law or regulation requires withholding of any taxes on
     payments with respect to Net Sales in any given country to Chiron, its
     affiliates or licensees, or on payments due to the Company hereunder,  such
     taxes will be deducted  on a country-by-country basis from such remittable
     payment, and the amounts due to


                                        3
<PAGE>


     the Company hereunder shall be remitted net of such withheld taxes.  Chiron
     shall provide the Company with documentation of any such withholding or
     other taxes paid hereunder with respect to tax liability of the Company.

     4.04.  BLOCKED CURRENCY.  If, in any country, the transfer of payment to
     Chiron,  its Affiliates or sublicensees with respect to Net Sales, or the
     transfer of royalties to the Company hereunder, is prohibited by law or
     regulation, the payment obligations to the Company hereunder with respect
     to the amounts so restricted shall be fully satisfied upon payment of the
     amounts due to the Company in local currency to a bank account in the
     Company's name in such country.  The parties agree to cooperate in their
     efforts to resolve any such blocked currency situation.


5.  AUDIT RIGHTS.  Chiron and its Affiliates agree to keep accurate books and
records of the sales of all Products.  The Company and Ciba shall have the
right, at Ciba's expense, for a period of three (3) years after each report
delivered pursuant to Section 4.02 to have an independent certified public
accountant ("CPA") reasonably acceptable to Chiron examine the relevant books
and records Chiron and its Affiliates, during normal business hours, at the
principal offices of Chiron or the Affiliate in question, upon two (2) weeks
advance written request, to verify the calculation of any royalty payment;
provided, however, that such audits shall not occur more than once per year.
Said CPA shall be under confidentiality obligations to Chiron and its
Affiliates, to reveal  only whether there is an error in the calculation of a
royalty payment owed hereunder, and if so, the amount of such error.

6.  ENTIRE AGREEMENT.  This Agreement, including any schedules and exhibits
hereto, constitutes the entire agreement of the parties with respect to the
subject matter hereof, and supersedes all prior agreements, negotiations and
understandings.  Without limiting the foregoing, this Agreement supersedes and
replaces in full that certain Royalty Agreement by and between Chiron and Chiron
Funding Corporation dated as of September 29, 1995.


                                        4
<PAGE>


     Executed by the parties as of the date first written above.

CHIRON CORPORATION                 CHIRON FUNDING L.L.C.


By                                 By
  ----------------------             ------------------------

Title                              Title
     -------------------                ---------------------


CHIRON BIOCINE COMPANY        BIOCINE S.P.A.

By                                 By
  ----------------------             ------------------------

Title                              Title
     -------------------                ---------------------


Schedules:  A       Products
            B       Base Net Sales


                                        5
<PAGE>


                                   SCHEDULE A

                     PRODUCTS ARISING FROM FUNDED PROJECTS
                         WHICH ARE SUBJECT TO ROYALTIES

                                 ADULT VACCINES

THE FOLLOWING SUBUNIT PROTEIN BASED VACCINES (DNA AND NUCLEOTIDE VACCINES ARE
EXCLUDED):

Herpes Simplex Virus Vaccine (prophylactic and therapeutic use)

Hepatitis C Virus Vaccine (prophylactic and therapeutic use)

Cytomegalovirus Vaccine

Adjuvanted Hepatitis B Vaccine

Human Papilloma Virus Vaccine

Human Immunodeficiency Virus Vaccine


                               PEDIATRIC VACCINES

THE FOLLOWING SUBUNIT PROTEIN BASED OR TRADITIONAL VACCINES (DNA AND NUCLEOTIDE
VACCINES ARE EXCLUDED):

Acellular Pertussis - Diphtheria - Tetanus Vaccine (aPDT) (but not acellular
pertussis, diphtheria or tetanus vaccines sold separately)

Meningococcus C Vaccine (Men C)

Haemophilus Influenza Vaccine (Hib)

Combinations of two or more of aPDT, Men C and Hib


                                      OTHER

Insulin-like Growth Factor 1


                                        6
<PAGE>


                                   SCHEDULE B

                     TOTAL NET SALES ON ALL PRODUCTS BY YEAR
                                (BASE NET SALES)

                            MILLIONS OF U.S. DOLLARS


<TABLE>
                    <S>            <C>
                    Q4   2001      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2002      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2003      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2004      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2005      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2006      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2007      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2008      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2009      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2010      $    [CONFIDENTIAL TREATMENT REQUESTED]
                         2011      $    [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>


                                        7