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                                                                   EXHIBIT 10.20


                          LICENSE AND SUPPLY AGREEMENT

          As Amended by Diaclone and Xcyte Therapies October 15, 1999

        This License and Supply Agreement ("Agreement") is entered into as of
October 15th, 1999 (the "Effective Date") by and between Xcyte Therapies, Inc.,
a Delaware corporation having a principal place of business at 2203 Airport Way
South, Suite 300, Seattle, Washington 98134, United States ("Xcyte"), and
Diaclone S.A., a French corporation having a principal place of business at 1
Boulevard Fleming, B.P. 1985 F-25020 Besancon Cedex, France ("Diaclone").

                                    RECITALS

        A. Diaclone has developed and owns the Licensed Materials (as defined
below).

        B. Xcyte desires to obtain, and Diaclone is willing to grant to Xcyte,
an exclusive worldwide license to the Licensed Materials for the development and
commercialization of Licensed Products (as defined below) within the Field (as
defined below), upon the terms and subject to the conditions of this Agreement.

        C. Xcyte desires to obtain form Diaclone, and Diaclone is willing to
manufacture and sell to Xcyte, the Licensed Antibody for use upon the terms and
subject to the conditions of this Agreement.

        Xcyte and Diaclone hereby agree as follows:

                                    AGREEMENT

        1. DEFINITIONS

        In addition to the terms defined elsewhere in this Agreement, the
following terms, whenever capitalized in this Agreement, shall have the
following meanings:

                1.1 "Affiliate" shall mean, with respect to a party, any entity
that controls, is controlled by, or is under common control of a party. For this
purpose, control of an entity shall mean direct or indirect ownership of fifty
percent (50%) or more of the voting interest in, or a fifty percent (50%) or
greater interest in the equity of, such corporation or other business entity, or
the maximum percentage allowed by law in the country of the controlled entity.

                1.2 "Diaclone" shall mean Diaclone S.A., a French corporation,
and its Affiliates.

                1.3 "FDA" shall mean the U.S. Food and Drug Administration or
any successor agency thereof.

                1.4 "Field" shall mean all ex vivo uses for (a) therapeutic
purposes and (b) research applications and purposes using or relating to the
Licensed Antibody or the Licensed Product.


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                1.5 "Licensed Antibody" shall mean the anti-CD28 antibody named
[*] produced by the Licensed Cell Line, and any modifications thereof made by
Xcyte or its sublicenses; provided, however, that in no event shall any antibody
that is not derived from the Licensed Materials and has been made with the use
of information or materials available in the public domain constitute a Licensed
Antibody.

                1.6 "Licensed Cell Line" shall mean the [*] cell line and all
progeny, clones, derivatives and modifications thereof.

                1.7 "Licensed Know-How" shall mean any and all technical
information, processes, compositions, formulae, data, engineering, materials,
reports, analyses, know-how, trade secrets and other subject matter owned and/or
controlled by Diaclone that is necessary or useful for the development,
manufacture and/or commercialization of Licensed Products in the Field.

                1.8 "Licensed Materials" shall mean, collectively, the Licensed
Antibody and the Licensed Cell Line.

                1.9 "Licensed Product" shall mean beads coated with the Licensed
Antibody and made with use of the Licensed Materials.

                1.10 "Net Sales" shall mean the gross amounts actually received
by Xcyte or its sublicensees from the sale of Licensed Products to Third
Parties, less (i) normal and customary rebates, and cash, quantity, trade and
other discounts, actually taken, (ii) sales, use, value added and/or other
similar taxes or duties actually paid, (iii) packaging, handling fees and
pre-paid shipping, freight and insurance, (iv) import and/or export duties
actually paid, and (v) amounts allowed or credited due to returns and the like.

                1.11 "Third Party" shall mean a party other than Xcyte, Diaclone
or their respective Affiliates.

                1.12 "Xcyte" shall mean Xcyte Therapies, Inc., a Delaware
corporation, and its Affiliates.

        2. LICENSE

                2.1 Grant of License. Diaclone hereby grants to Xcyte a
worldwide, exclusive license under the Licensed Materials and Licensed Know-How,
with the right to grant and authorize sublicenses, to make, have made, import,
have imported, use, offer for sale, sell and otherwise distribute Licensed
Products, practice any method, process or procedure, or otherwise exploit, in
each case, Licensed Materials and Licensed Know-How for use in the Field (the
"License").

                2.2 Transfer of Licensed Materials. Within ninety (90) days
after the Effective Date, Diaclone shall transfer to Xcyte all proprietary
technical data, methods and processes, and other information (in electronic and
hard copy formats) and data in the possession or control of

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Diaclone relating to the Licensed Materials. In addition, upon request by Xcyte,
Diaclone shall transfer to Xcyte a viable culture of the cell bank for the
Licensed Cell Line, and Xcyte agrees to only use such cell bank as contemplated
by and in accordance with this Agreement.

                2.3 Sublicensing. Xcyte may grant and authorize sublicenses
within the scope of the License. Upon request by Diaclone, Xcyte shall provide
Diaclone with a copy, subject to the confidentiality provisions of Section 13,
of the relevant terms of any sublicense agreement necessary to determine the
rights granted under any Licensed Materials and the Licensed Know-How and the
amounts due to Diaclone hereunder.

                2.4 Option to Expand Field. Subject to all of the terms and
conditions of this Agreement, Xcyte shall have an option (the "Option"),
exercisable at any time upon written notice to Diaclone, to expand the Field
hereunder to include [*] using or relating to the Licensed Antibody or the
Licensed Product (the "Expanded Field"). The exercise of the Option shall be
subject to the payment by Xcyte of a license fee in the amount of $75,000 and
any future royalty payments pursuant to Section 6.3 with respect to the Expanded
Field. Upon exercise of the Option in accordance with this Section 2.4, without
further action of the parties, the Field shall automatically be amended to
include the Expanded Field.

                2.5 Right of First Refusal. In the event that, prior to the
exercise of the Option by Xcyte, Diaclone shall agree with a Third Party upon
the terms and conditions of a proposed license to such Third Party that would
license to any extent the Licensed Materials in the Expanded Field, Diaclone
shall provide written notice to Xcyte setting forth such proposed terms and
conditions (the "Notice"), and Xcyte shall have a right of first refusal (the
"Right of First Refusal") to enter into an agreement with Diaclone on such terms
and conditions. Thereafter, Xcyte shall have a period of thirty (30) days in
which to exercise the Right of First Refusal by written notice to Diaclone,
during which period Diaclone shall not enter into such license with such Third
Party. Upon exercise of the Right of First Refusal by Xcyte, the parties shall
negotiate in good faith to enter into agreement on such terms and conditions as
soon as reasonably practicable. In the event that Xcyte does not exercise the
Right of First Refusal within such thirty (30)-day period, Diaclone shall have a
period of sixty (60) days in which to grant such license to such Third Party of
the Licensed Materials within the Expanded Field on terms no more favorable to
such Third Party than those set forth in the Notice. In the event that Diaclone
does not enter into such an agreement during such sixty (60)-day period,
Diaclone may not enter into such an agreement without sending a new or revised
Notice and complying with the terms and conditions of this Section 2.5. Upon
receipt of the Notice by Xcyte, the Option shall not be exercisable by Xcyte
unless and until (a) Xcyte fails to exercise the Right of First Refusal, and (b)
Diaclone does not enter into such an agreement with such Third Party within such
sixty (60)-day period.


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        3. MANUFACTURE AND PURCHASE OF LICENSED ANTIBODY

                3.1 Manufacture

                        (a) Production. Diaclone agrees to produce and test the
bulk Licensed Antibody at its facilities located at 1 boulevard Fleming, B.P.
1985 F-25020 Besangon Cedex, France ("Facilities") and to sell the Licensed
Antibody to Xcyte upon the terms and subject to the conditions of this
Agreement. Diaclone shall manufacture and sell the Licensed Antibody for and to
Xcyte on an exclusive basis for all uses within the Field, and Diaclone shall
not manufacture or sell the Licensed Antibody for or to any Third Party for any
use or purpose within the Field. Except as set forth in Section 4, Xcyte shall
purchase the Licensed Antibody from Diacline on an exclusive basis. All Licensed
Antibody provided to Xcyte by Diaclone will be produced in accordance with the
manufacturing procedures identified in Exhibit A attached hereto ("Production
Protocol"), will meet the specifications identified in Exhibit B attached hereto
("Specifications") and will be manufactured in accordance with "Good
Manufacturing Practices." Diaclone will qualify the Licensed Cell Line as
described in Exhibit C attached hereto ("Licensed Cell Line Qualification") and
comply with the process validation requirements described in Exhibit D attached
hereto. Diaclone shall not use the Specifications or the Production Protocol in
connection with the performance of services for any Third Party.

                        (b) Changes. Diaclone may not make any changes to the
Production Protocol, Specifications, or Licensed Cell Line Qualification without
the prior written approval of Xcyte, which approval will not be unreasonably
withheld. Diaclone will, however, agree to any such changes as are reasonably
requested by Xcyte. Diaclone will have in place a documentation, control and
change system that complies with Good Manufacturing Practices and other
applicable rules, regulations and standards of the FDA, as well as any other
applicable regulatory standards for the intended use of the Licensed Antibody,
as such requirements may change from time to time ("Regulatory Standards"), and
all changes made under this Section will conform to such Regulatory Standards.
Any such changes will be made in writing and signed by authorized
representatives of each party.

                        (c) Initial Quantity. Diaclone shall manufacture for
Xcyte an initial quantity of [*] of purified bulk Licensed Antibody (the
"Initial Quantity").

                3.2 Purchase and Supply

                        (a) Amount. No later than ________, 1999, Diaclone will
provide to Xcyte the Initial Quantity. Thereafter, Xcyte may, in its sole and
absolute discretion, order additional purified bulk Licensed Antibody in amounts
in excess of the Initial Quantity ("Additional Licensed Antibody") as set forth
in Section 3.2(b). If Xcyte orders Additional Licensed Antibody, Diaclone will
produce, sell and deliver such Additional Licensed Antibody to Xcyte in
accordance with the terms of this Agreement upon delivery dates that are
reasonable and mutually agreed to by the parties. Xcyte will be obligated to
purchase such Additional Licensed Antibody.


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                        (b) Order Procedure. Xcyte will order Licensed Antibody
under this Agreement by executing and issuing to Diaclone a purchase order
("Purchase Order") which will specify the reasonable amount of Licensed Antibody
ordered, reasonable delivery dates, place of delivery, pricing pursuant to
Section 6.1 and any other additional terms agreed to by the parties. Each such
Purchase Order will be automatically binding upon and enforceable against
Diaclone upon delivery by Xcyte if in material conformity with the
Specifications and the terms and conditions of this Agreement. In all other
cases, a Purchase Order will be binding upon Diaclone upon (x) written
acceptance by Diaclone or (y) the failure by Diaclone to object to such Purchase
Order (including objection to the specified delivery dates, which shall be
reasonable and mutually agreed by the parties, as set forth in Section 3.2(a))
in writing within fifteen (15) days of receipt thereof. A Purchase Order may not
be amended except by a written amendment executed according to Section 13.3.
Diaclone will notify Xcyte immediately if it determines that it will not be able
to meet any of the terms of a Purchase Order, including, but not limited to,
delivery dates. In addition, Diaclone will notify Xcyte promptly of any supply
constraints (e.g., materials, third party contracts, facilities or capacity) of
which it becomes aware that may affect its ability to supply the Licensed
Antibody in accordance with the terms of any Purchase Order. No such
notification by Diaclone or acknowledgment of such notification by Xcyte will
relieve Diaclone of any liability for a breach of this Agreement or a Purchase
Order.

                3.3 [*]. As set forth in Section 6.1(d), Xcyte shall reimburse
Diaclone for [*] of the Licensed Antibody for Xcyte hereunder (the [*]);
provided, however, that Diaclone shall not use any [*] for any purpose other
than the [*] of the Licensed Antibody for Xcyte pursuant to this Agreement, and
Diaclone agrees, upon Xcyte's request and [*] following any termination or
expiration of this Agreement. The [*] and their respective estimated costs are
set forth on Exhibit E attached hereto.

                3.4 Biosafety Testing. Diaclone agrees to conduct, at Xcyte's
expense, biosafety testing (the "Biosafety Testing") on all Licensed Antibody to
be provided to Xcyte hereunder and under any Purchase Order. The specifications
of the tests included in the Biosafety Testing, and the estimated costs
therefor, are set forth in Exhibit F attached hereto. Diaclone shall provide to
Xcyte all data, results and materials relating to the Biosafety Testing.

                3.5 Status Conferences. Diaclone will, at the request of Xcyte,
meet by telephone or otherwise to discuss with Xcyte the status of any Licensed
Antibody ordered by Xcyte and not yet delivered by Diaclone.

                3.6 Back-up Cell Bank; Segregation of Licensed Antibody.
Diaclone will at all times have a back-up master cell bank for the Licensed Cell
Line (minimum of five (5) vials) stored at some location other than the
Facilities to minimize any risk of loss that could threaten the master cell bank
located at the Facilities. If requested by Xcyte, Diaclone will, subject to
space and storage limitations, segregate Licensed Antibody, including, but not
limited to, the Initial Quantity, upon completion of manufacture thereof until
shipment.

                3.7 [*] Equipment and Materials. Any tooling, test equipment or
other equipment or material [*] for purposes of performing its obligations
hereunder [*] will remain at

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all times [*] such equipment or material (a) may not [*] without Xcyte's prior
written consent, (b) may be used only for the purpose of producing the Licensed
Antibody or other products produced by Diaclone for Xcyte as agreed by the
parties and (c) [*] all subject to Xcyte's instructions. Diaclone will reimburse
Xcyte [*]. All such equipment and material will be included, to the extent
applicable, in Diaclone' calibration and document control programs, subject to
Xcyte's prior written authorization.

                3.8 Ownership of Licensed Antibody. The parties acknowledge and
agree that Xcyte is the sole owner of all Licensed Antibody provided to Xcyte by
Diaclone pursuant to this Agreement. Diaclone agrees to take any action deemed
by Xcyte to be necessary or appropriate to vest such ownership position in Xcyte
and to transfer and assign all right, title and interest held by Diaclone in
such Licensed Antibody to Xcyte.

        4. THIRD PARTY SUPPLY.

                4.1 Failure to Supply. If (a) Diaclone materially fails to
comply with the Regulatory Standards for a period of six (6) months or some
lesser time as reasonably determined by Xcyte based on the severity of the
violation, (b) Diaclone cannot (or does not wish to) produce Licensed Antibody
of the quality, in the quantity or within the time frame reasonably required by
Xcyte (with the applicable time frame being within thirty (30) days of the
delivery date specified in the applicable Purchase Order, or within ninety (90)
days in the case of a force majeure event as described in Section 11, provided
that Diaclone is in compliance with the provisions of Section 11), (c) Diaclone
either does not have or loses the right to use any of the technology required to
produce and test the Licensed Antibody in accordance with the Specifications,
the Production Protocol and any other specifications agreed upon by the parties,
including, without limitation, use of viral inactivation technology acceptable
to Xcyte and in compliance with the Regulatory Standards, or (d) one or more
parties (other than parties that currently have an ownership interest in
Diaclone) obtains the ability, through on ownership interest in the capital
stock or assets of Diaclone or by other means, to influence existing or future
terms of this Agreement or Diaclone's performance hereunder, then Xcyte may, in
addition to all other remedies it may have under this Agreement or otherwise, at
its sole option, elect to have one or more Third Parties manufacture and supply
the Licensed Antibody and/or produce the Licensed Antibody itself.

                4.2 Phase III Clinical Trials. At such time as Xcyte is
preparing for the commencement of Phase III Clinical Trials relating to the
Licensed Materials or Licensed Product, Xcyte may, at its sole option, elect to
have one or more Third Parties manufacture and supply the Licensed Antibody
and/or produce the Licensed Antibody itself.

                4.3 Assistance. In the event that Xcyte shall elect to have one
or more Third Parties manufacture and supply the Licensed Antibody and/or
produce the Licensed Antibody itself pursuant to Section 4.1 or Section 4.2,
Diaclone shall, upon Xcyte's request, promptly transfer a minimum of [*] of the
master cell bank for the Licensed Cell Line to Xcyte or any such Third Party. In
addition, Diaclone shall provide to Xcyte and/or any such Third Party all
necessary information and cooperation to enable Xcyte or such Third Party to
manufacture the


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Licensed Antibody in accordance with the Specifications and the Production
Protocol. If requested by Xcyte, Diaclone will assist Xcyte in locating an
appropriate Third Party manufacturer to produce the Licensed Antibody.

        5. QUALITY CONTROL, LEGAL, REGULATORY STANDARDS

                5.1 [*] Testing. Diaclone will perform [*] supplied to Xcyte
hereunder in accordance with Diaclone's standard operating procedures as
approved by Xcyte. [*]

                5.2 Compliance with Law and Regulation. Diaclone will comply
with all international, national, state and local laws, ordinances, rules and
regulations applicable to the conduct of its business, including, but not
limited to, the Regulatory Standards, in performing its obligations hereunder
and will maintain, during the term of this Agreement, a manufacturing facility,
personnel and quality control and quality assurance programs that comply with
the Regulatory Standards. In the event that regulatory certification is required
for the manufacture, sale or distribution of Licensed Materials, Diaclone will
ensure that such certification is met at its own expense.

                5.3 Contacts with Regulatory Bodies. Diaclone will advise Xcyte
of all contacts with any regulatory agency concerning the Licensed Antibody and,
upon request, will provide Xcyte with copies of all materials regarding the
Licensed Antibody that it submits to any regulatory agency or that are provided
by any regulatory agency to Diaclone.

                [*]

                5.5 Records Retention. All records relating to the manufacture
of the Licensed Antibody and the fulfillment of each Purchase Order, including
all Lot History Records, will be retained for a period of at least five (5)
years from the date of manufacture. Prior to the destruction of any such
records, written notice will be provided to Xcyte, and Xcyte will have the right
to request and retain them.

                5.6 Changes to Facilities. Diaclone will notify Xcyte in writing
not less than ninety (90) days prior to making any change in the Facilities [*]
No such change will be made by Diaclone without Xcyte's prior written approval,
which approval may be granted or withheld in Xcyte's sole discretion.

                5.7 Product Recall. Xcyte and Diaclone each will notify the
other promptly if the Licensed Antibody or a Licensed Product alleged or proven
to be the subject of a recall, market withdrawal or correction and the parties
will cooperate in the handling and disposition of any such recall, market
withdrawal or correction; provided, however, that in the event of a disagreement
as to any matter related to such recall, market withdrawal or correction, Xcyte
will have final authority.

                5.8 Cooperation Regarding Regulatory Approval. Diaclone will
provide to Xcyte [*]. Additionally, Diaclone agrees to provide Xcyte with any
assistance reasonably requested by Xcyte in obtaining such governmental
approvals, including, without limitation, the

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furnishing of all technical information, processes, formulae, data, engineering,
materials, know-how and trade secrets owned or controlled by Diaclone that are
relevant to the development and manufacture of the Licensed Materials available
to Diaclone and its Affiliates.

        6. SUPPLY PRICING; LICENSEE FEE; ROYALTIES

                6.1 Supply Pricing.

                        (a) Price Per Gram. Subject to the provisions of this
Section 6.1, the price to be paid for purchase of Licensed Antibody during the
term of this Agreement shall be [*] per gram of Licensed Antibody.

                        (b) Initial Quantity. Xcyte shall pay to Diaclone [*]
within thirty (30) days of acceptance by Xcyte of the Initial Quantity. Such
payments shall be non-refundable, except as set forth in Section 8.1(c).

                        (c) [*] Xcyte shall [*] that are approved in writing in
advance by Xcyte (provided that Xcyte shall also approve the price of such [*]
in the event that the price therefor materially differs from the price set forth
on Exhibit E attached hereto) within forty-five (45) days of receipt of an
undisputed invoice with respect thereto from Diaclone.

                        (d) Biosafety Testing. Diaclone shall conduct and pay
for the Biosafety Testing in accordance with Exhibit F attached hereto (provided
that Xcyte shall pre-approve any costs that materially differ from the estimated
costs set forth in Exhibit F attached hereto) and invoice Xcyte for
reimbursement. Xcyte shall pay all undisputed amounts on such invoice within
forty-five (45) days of receipt thereof.

                        (e) Cell Banks. Within forty-five (45) days of receipt
of an invoice from Diaclone with respect thereto, Xcyte [*] The parties
acknowledge and agree that Xcyte [*] the parties anticipate that the remainder
of such costs will be an additional amount of approximately [*]

                        (f) Invoicing for Licensed Antibody. Diaclone will
invoice Xcyte, in duplicate, accompanied (if applicable) by a bill of lading or
airway bill, for all Licensed Antibody purchased hereunder promptly upon
delivery of such Licensed Antibody pursuant to Section 8. The price per gram set
forth in Section 6.1(a) is inclusive of all costs payable by Xcyte for purchase
of the Licensed Antibody. Xcyte will, under no circumstances, be responsible for
any costs in addition to such amounts, including, without limitation, costs for
activities performed by Biotest AG or any other Affiliate of Diaclone. Diaclone
will indemnify Xcyte for any such additional costs.

                6.2 License Fee. In consideration of the License, Xcyte shall
pay the following fees to Diaclone at the following times: [*] within six (6)
months of the receipt by Diaclone of the payment set forth in the preceding
clause (b).

                6.3 Royalties


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                        (a) Royalties on Net Sales. Subject to the other
provisions of this Section 6.3, Xcyte shall pay to Diaclone, on a
product-by-product basis, a royalty [*] of Net Sales. Following the first
approval by the FDA or its foreign equivalent of a Licensed Product for
therapeutic uses, the amount payable to Diaclone by Xcyte under this Section 6.3
for all Licensed Products used for therapeutic uses shall be, at a minimum, [*]
By way of clarification, such minimum annual amounts shall not be reduced in any
manner by the provisions of Sections 6.3(b) or 6.3(c) below.

                        (b) Combination Products. In the event that a Licensed
Product is used or sold by Xcyte in combination as a single product without or
more other product(s) or service(s) which are not Licensed Products, Net Sales
from such sales and/or use for purposes of calculating the amounts due under
Section 6.3(a) above shall be calculated by multiplying the Net Sales of that
combination by the fraction A/(A + B), where A is the gross selling price of the
Licensed Product sold separately and B is the gross selling price of the other
product or service sold separately. In the event that no such separate sales or
use of a Licensed Product are made by Xcyte, Net Sales for royalty determination
shall be calculated by Multiplying Xcyte's cost for making or having made a
Licensed Product ("Cost") by 1.5 (i.e., Cost x 1.5). It is understood and agreed
that Xcyte intends to use Licensed Products in connection with products and
services which do not entail the use of the Licensed Materials, and that such
Licensed Products shall be subject to this Section 6.3(b).

                        (c) Third Party Offsets. In the event that Xcyte enters
into any license or other agreement with a third party with respect to
intellectual property or inputs protected by intellectual property which is
necessary or useful for the manufacture, use or sale of a Licensed Product,
Xcyte may offset any amounts paid to such third party thereunder against
royalties otherwise due Diaclone pursuant to this Section 6.3; provided,
however, that the royalties that would otherwise be due to Diaclone may not be
reduced by more than [*]

                        (d) One Royalty. For purposes of clarity, the parties
acknowledge and agree that no more than one royalty payment shall be due with
respect to a sale of a particular Licensed Product. In addition, no royalty
shall be payable under this Section 6.3 with respect to Licensed Products
distributed for use in research and/or development, in clinical trials or as
promotional samples.

        7. PAYMENT; REPORTS AND RECORDS

                7.1 Timing of Royalty Payments; Payment Method. Xcyte agrees to
pay all royalties due to Diaclone within sixty (60) days of the last day of the
calendar quarter in which such royalties accrue.

                7.2 Royalty Reports. Xcyte shall deliver to Diaclone within
ninety (90) days after the end of each calendar quarter in which Licensed
Products are sold a report setting forth in reasonable detail the calculation of
the royalties payable to Diaclone for such calendar quarter, including the
Licensed Products sold in each country, the Net Sales thereof, and all amounts


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received from sublicensees for sales of Licensed Products. Such reports shall be
Confidential Information of Xcyte subject to Section 13.

                7.3 Currency; Foreign Payments. All payments due hereunder shall
be paid in United States dollars. If any currency conversion shall be required
in connection with the payment of any royalties hereunder, such conversion shall
be made by using the exchange rate for the purchase of U.S. Dollars reported by
the Bank of America on the last business day of the calendar quarter to which
such royalty payments relate. If at any time legal restrictions prevent the
prompt remittance of any royalties owed with respect to Net Sales in any
jurisdiction, Xcyte may notify Diaclone and make such payments by depositing the
amount thereof in local currency in a bank account or other depository in such
country in the name of Diaclone, and Xcyte shall have no further obligations
under this Agreement with respect thereto.

                7.4 Inspection of Books and Records. Xcyte shall maintain
accurate books and records which enable the calculation of royalties payable
hereunder to be verified. Xcyte shall retain the books and records for each
quarterly period for three (3) years after the submission of the corresponding
report under Section 7.2. Upon thirty (30) days prior notice to Xcyte,
independent accountants selected by Diaclone and reasonably acceptable to Xcyte,
after entering into a confidentiality agreement with Xcyte, may have access to
Xcyte's books and records to conduct a review or audit once per calendar year,
for the sole purpose of verifying the accuracy of Xcyte's payments and
compliance with this Agreement. The accounting firm shall report to Diaclone
only whether there has been a royalty underpayment and, if so, the amount
thereof. Such access shall be permitted during Xcyte's normal business hours
during the term of this Agreement and for two (2) years after the expiration or
termination of this Agreement. Any such inspection or audit shall be at
Diaclone' expense; provided, however, that in the event that an inspection
reveals an underpayment of [*] or more in any audit period, Xcyte shall pay the
costs of such inspection and promptly pay to Diaclone any underpayment.

                7.5 Taxes. All royalty amounts required to be paid to Diaclone
pursuant to this Agreement may be paid with deduction for withholding for or on
account of any taxes (other than taxes imposed on or measured by net income) or
similar government charge imposed by a jurisdiction other than the United States
("Withholding Taxes"). At Diaclone's request, Xcyte shall provide Diaclone a
certificate evidencing payment of any Withholding Taxes hereunder and shall
reasonably assist Diaclone to obtain the benefit of any applicable tax treaty.

                7.6 Payment. The prices stated in the Pricing Schedule and
referenced in each Purchase Order are stated in United States Dollars, and do
not include sales, use, excise or any other similar taxes imposed by
international, federal, state or local governments, or shipping charges. Such
prices are inclusive of handling and all other charges unless otherwise
specifically provided in the Pricing Schedule or Purchase Order. Taxes and
shipping charges will be itemized separately in each invoice. Unless otherwise
provided in the Purchase Order, terms of payment will be net forty-five (45)
days from Xcyte's receipt of the Licensed Antibody or invoice, whichever occurs
later, subject to Xcyte's acceptance of the Licensed Antibody and the resolution
of any good faith disputes relating to the invoiced amount. No payment of an
invoice will be deemed to constitute acceptance of the Licensed Antibody by
Xcyte. If Xcyte disputes

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any invoice, Xcyte will, within forty-five (45) days of receipt of such invoice,
notify Diaclone that it disputes the accuracy or appropriateness of such invoice
and provide the basis for such dispute.

        8. DELIVERY; ACCEPTANCE

                8.1 Documentation, Inspection

                        (a) Documentation. With each shipment of Licensed
Antibody to Xcyte under this Agreement or any Purchase Order, Diaclone will send
a copy of the lot history record, [*] In addition, Diaclone will provide a
material safety data sheet for the Licensed Antibody and any other documentation
required by the Specifications or requested by Xcyte. Any substitution,
reprocessing or reworking of the Licensed Antibody must be reported to and
approved by Xcyte before any Licensed Antibody subject to such variances may be
shipped. Any substituted, reprocessed or reworked Licensed Antibody must be
accompanied by variance and nonconformance data in addition to the documentation
described above.

                        (b) Acceptance and Rejection All Licensed Antibody
delivered under this Agreement will be inspected and tested by Xcyte or its
designee using Xcyte's standard testing procedures. Xcyte will give notice by
facsimile of its rejection or acceptance of any Licensed Antibody within sixty
(60) days of receipt thereof.

                        (c) Non-Conformance. Notwithstanding the completion of
such inspection or the passing of the date for notice of rejection under Section
8.1 (b), if any Licensed Antibody is found at any time by Xcyte, or its
customers or users of the Licensed Antibody or a Xcyte product in which the
Licensed Antibody was incorporated, to be defective or not in conformity with
the Specifications, or if Xcyte is not satisfied with the results of the
Biosafety Testing, Xcyte may, at its option: (i) reject such Licensed Antibody,
require Diaclone to replace such Licensed Antibody at Diaclone's expense (other
than costs of Biosafety Testing and [*] which shall be borne by Xcyte in
accordance with Sections 3.3 and 3.4) and provide notice to Xcyte that any
Licensed Antibody delivered is replacement Licensed Antibody, provided that if
Diaclone is unable to replace such Licensed Antibody within the time period
specified in Section 4.1, or such other time period as may be agreed by the
parties, then Xcyte may exercise its option for the manufacturing rights set
forth in Section 4, or (ii) notwithstanding anything to the contrary in this
Agreement, request a refund of all amounts paid to Diaclone hereunder in
connection with such Licensed Antibody (other than payments made with respect to
Biosafety Testing and [*] in accordance with Sections 3.3 and 3.4), in which
case Diaclone will promptly refund such amounts; provided, however, that
Diaclone shall be entitled to retain [*] with respect to each [*] of such
Licensed Antibody if such Licensed Antibody is not defective.

                8.2 Shipping and Delivery

                        (a) Shipping. Unless otherwise specified in the Purchase
Order, all freight expenses for delivery of the Licensed Antibody will be
prepaid by Diaclone and added to Diaclone's invoice to Xcyte for payment by
Xcyte. Xcyte will obtain permits for importation of the Licensed Antibody into
the United States and other countries as appropriate. No Licensed

*Certain information on this page has been omitted and filed
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 been requested with respect to the omitted portions.


                                      -11-
<PAGE>   12

Antibody may be shipped to Xcyte's designated destination until the appropriate
import permits have been obtained, and Diaclone shall assist Xcyte, upon request
of Xcyte, in obtaining approvals of regulatory agencies in the applicable
jurisdictions for importation of the Licensed Antibody. Diaclone shall be
responsible for exporting the Licensed Antibody from France or such other
location in which Diaclone may manufacture the Licensed Antibody in accordance
with this Agreement and shall obtain any necessary export licenses or approvals
required for such export.

                        (b) Delivery. Unless otherwise specified in the Purchase
Order, the FOB point will be the location designated by Xcyte in the Purchase
Order for delivery of the Licensed Antibody. Diaclone will bear all risk of loss
or damages to the Licensed Antibody, and title to the Licensed Antibody will not
transfer to Xcyte until delivery of the Licensed Antibody (including any
Licensed Antibody segregated in accordance with Section 3.6 prior to shipment)
to Xcyte's designated location.

        9. REPRESENTATIONS AND WARRANTIES. In addition to all other express or
implied warranties, Diaclone represents and warrants that it has the right (a)
to use all technology it employs in the production, use and sale of the Licensed
Antibody hereunder, (b) to grant all licenses granted or to be granted hereunder
and (c) to perform all of its other obligations under this Agreement. Diaclone
further represents and warrants that its Facilities will be maintained as
required herein and that the Licensed Antibody (i) will meet the Specifications,
(ii) will be manufactured in accordance with the Production Protocol and "Good
Manufacturing Practices," (iii) will be free from all liens and security
interests such that full ownership rights vest in Xcyte, and (iv) has been
developed, labeled, packaged, manufactured, tested, stored, supplied and sold in
accordance with the terms of this Agreement [*] Diaclone represents and warrants
that (A) the execution, delivery and performance of this Agreement does not
conflict with, violate or breach any agreement to which Diaclone is a party (B)
Diaclone has not received written notice that the Licensed Materials infringe
upon the intellectual property rights of any third party, (C) there are no
threatened or pending actions, suits, investigations, claims or proceedings in
any way relating to the Licensed Materials to which Diaclone is a party or of
which Diaclone is aware, and (D) it is the exclusive owner of all right, title
and interest in the Licensed Materials.

        10. TERM AND TERMINATION

                10.1 Term. The term of this Agreement will begin on the
Effective Date and will continue, subject to early termination as provided in
Section 10.2, for a period of fifteen (15) years from the date of first
approval by FDA or its foreign equivalent of a Licensed Product for therapeutic
uses. At the end of the fifteen (15) years, Xcyte will have a perpetual,
irrevocable, fully paid up, royalty free exclusive license to the Licensed
Materials and Licensed Know-Row with all of the rights granted in Section 2.1.

                10.2 Termination. This Agreement may be terminated as follows:

                        (a) Xcyte may terminate this Agreement at any time upon
thirty (30) days written notice to Diaclone;

                        (b) Either party may terminate this Agreement in the
event of a material breach by the other party provided that the defaulting party
fails to cure such breach within thirty (30) days after receipt of notice of
such breach, or in the case of a breach that is not


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                                      -12-
<PAGE>   13

capable of cure within thirty (30) days, if the defaulting party fails to begin
cure within thirty (30) days after receipt of notice of such breach or to
continue to pursue such cure diligently thereafter;

                        (c) Either party may terminate in the event of (i) the
making by either party of any general assignment for the benefit of creditors,
(ii) the filing by or against either party of a petition for reorganization or
arrangement under any law relating to bankruptcy (unless, in the case of a
petition filed against such party, the same is dismissed within sixty (60)
days), (iii) the appointment if a trustee or receiver to take possession of
substantially all of either party's assets, where possession is not restored to
such party within sixty (60) days, or (iv) the attachment, execution or other
judicial seizure of substantially all of either party's assets, where such
seizure is not discharged within sixty (60) days; or

                10.3 Effect of Termination. Neither party will be relieved of
any obligations incurred under this Agreement prior to the date of such
termination or expiration thereof, and the provisions of Sections 1, 3.6, 3.8,
4, 5.8, 7.4, 9, 10, 12, 13, 14, 15, and 16 will survive any such termination or
expiration.

        11. FORCE MAJEURE

                11.1 No Liability. Neither party will be liable for any failure
to fulfill any term or condition of this Agreement, other than the payment of
amounts owed hereunder, nor will such failure constitute a breach of or default
under this Agreement, if fulfillment has been delayed, hindered or prevented by
an event of force majeure, including any war, riot, strike, acts of the
elements, acts or compliance with any order of any government or agency thereof
(including the enactment of any new laws, rules or regulations), sabotage or
industrial accident, where the failure to perform is beyond the reasonable
control and not caused by the negligence or intentional misconduct of the
non-performing party, and the non-performing party has exerted all reasonable
efforts to avoid or remedy the force majeure.

                11.2 Notice of Force Majeure. Promptly following the date any
event of force majeure occurs, the party so affected will advise the other party
in writing of the date and nature of the event and the period of time such event
is expected to continue. During the existence of such event, the duties and
obligations of the parties under this Agreement will be suspended and the
parties will take all reasonable action to ensure resumption of normal
performance under this Agreement as soon as possible.

                11.3 Termination Right. If, as a result of any such force
majeure event, a party is unable to fully perform its obligations hereunder for
a period of ninety (90) days, the other party will have the right to terminate
this Agreement upon written notice, effective the date of such notice.

        12. INDEMNIFICATION; LIMITATION OF LIABILITY



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                                      -13-
<PAGE>   14

                12.1 By Diaclone. Diaclone will defend, indemnify and hold
harmless Xcyte and its officers, directors, employees and agents (collectively,
"Indemnitee") from and against any and all losses, damages, liability,
settlement costs, defense costs, other expenses and attorneys' fees (a
"Liability") resulting from a Third Party claim or suit related to or arising
out of the development, labeling, packaging, manufacturing, storage, testing, or
supply of Licensed Antibody or any breach of this Agreement by Diaclone,
including, without limitation, breach of any representation or warranty
contained herein.

                12.2 By Xcyte. Xcyte shall defend, indemnify and hold harmless
Diaclone and its officers, directors, employees and agents (collectively,
"Indemnitee") from and against any and all Liabilities resulting from a Third
Party claim or suit relating to or arising out of the development, labeling,
packaging, manufacturing, storage, testing or sale of any Licensed Product by
Xcyte or any breach of this Agreement by Xcyte, including, without limitation,
breach of any representation or warranty contained herein.

                12.3 Procedure. In the event that any Indemnitee intends to
claim indemnification under this Section 12 it shall promptly notify the
indemnifying party in writing of such alleged Liability. The indemnifying party
shall have the right to control the defense and settlement thereof. The
Indemnities shall cooperate with the indemnifying party and its legal
representatives in the investigation of any action, claim or liability covered
by this Section 12. The Indemnitee shall not, except at its own cost,
voluntarily make any payment or incur any expense with respect to any claim or
suit without the prior written consent of the indemnifying party, which the
indemnifying party shall not be required to give. 12.4 LIMITATION OF LIABILITY.
NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY SPECIAL, CONSEQUENTIAL,
INCIDENTAL OR INDIRECT DAMAGES ARISING OUT OF THIS AGREEMENT, HOWEVER CAUSED,
UNDER ANY THEORY OF LIABILITY.

        13. CONFIDENTIALITY

                13.1 Confidential Information. "Confidential Information" will
include, but not be limited to, any information marked as confidential and all
know-how, formulas, specifications, processes, product ideas, inventions and
technical, business and financial plans, forecasts and strategies, and any
information derived therefrom disclosed by either party to the other. Each party
will hold in confidence and not use or disclose to others, except as
specifically authorized by this Agreement, the Confidential Information of the
other. Each party will protect the other party's Confidential Information by
using the same degree of care, but not less than a reasonable degree of care,
used to protect its own Confidential Information. Diaclone acknowledges that the
Specifications, the Production Protocol, the quantity of the Licensed Antibody
ordered or used by Xcyte and the quantity of Xcyte's product sold by Xcyte are
Confidential Information of Xcyte.

        This restriction does not apply to the extent it can be established by
the receiving party that the information:



                                      -14-
<PAGE>   15

                        (a) was known to the receiving party at the time of
disclosure;

                        (b) was part of the public domain at the time of
disclosure or later entered the public domain through no fault of the receiving
party;

                        (c) was made known to the receiving party from another
source under no obligation to the disclosing party; or

                        (d) was independently developed by the receiving party
without the use of the disclosing party's Confidential Information.

        Notwithstanding the above, each party may disclose the other party's
Confidential Information: (i) to employees or agents to the extent necessary to
accomplish the purposes of this Agreement, provided that each such individual is
first bound by an obligation of confidentiality equivalent to that described
herein, (ii) to the extent necessary to comply with applicable laws, judicial
orders or governmental regulations provided that each party agrees to give
reasonable advance notice to the other of any such intended disclosure, and to
minimize such disclosure to the extent possible, and (iii) to governmental
agencies to obtain approval for commercial sale of the Licensed Antibody or any
of Xcyte's products. Each party's Confidential Information will remain the
property of that party, and the disclosure of Confidential Information hereunder
does not constitute a grant of any right or license to such Information. The
restrictions described in this Section 13 will remain in effect for five (5)
years after termination of this Agreement.

                13.2 Test Results. Diaclone specifically agrees that the results
of any tests performed on the Licensed Cell Line or Licensed Antibody that are
paid for by Xcyte belong solely to Xcyte, are part of Xcyte's Confidential
Information and are subject to the protections described in this section.
Diaclone further agrees that such information will not be used by Diaclone for
any purpose other than to produce Licensed Antibody for Xcyte as described in
this Agreement, or be used by or for the benefit of any third party without
Xcyte prior consent.

                13.3 Equitable Relief. The parties agree that due to the unique
nature of the Confidential Information, there can be no adequate remedy at law
for any breach of the receiving party's obligations under this Agreement,
thereby resulting in irreparable harm to the disclosing party. Therefore,
notwithstanding Section 16.6 hereof, upon any such breach of this Section 13 or
any threat thereof, the disclosing party shall be entitled to seek appropriate
mandatory or negative injunctive relief.

        14. INTELLECTUAL PROPERTY.

                14.1 Reservation of Rights. For purposes of this Section 14,
"Intellectual Property" will mean all intellectual property, tangible or
intangible including, without limitation, any and all data, techniques,
inventions, discoveries, ideas, processes, know-how, patents, patent
applications, trade secrets, and other proprietary information. Except as
expressly stated herein, neither party grants any right or license to any of its
Intellectual Property to the other party, and the disclosure of Confidential
Information by either party to the other will not obligate the



                                      -15-
<PAGE>   16

disclosing party to grant rights in or to the subject matter of such
Confidential Information to the receiving party.

                14.2 Ownership. All Intellectual Property pertaining to the
development, manufacture or use of the Licensed Materials will be owned by the
inventor as determined under United States patent law. Any such Intellectual
Property which is invented jointly by the parties ("Joint Intellectual
Property") will be jointly owned by the parties. All patent applications on the
Joint Intellectual Property will be agreed to by each of the parties and filed,
prosecuted and maintained jointly by the parties at their joint expense. Any
such Joint Intellectual Property may be used (or sublicensed) by either Diaclone
or Xcyte worldwide for any purpose without accounting to the other. If for any
reason Diaclone or Xcyte declines to participate in the filing, prosecution, or
maintenance of any patent application or patent on the Joint Intellectual
Property, (other than Joint Intellectual Property governed by Section 14.3), the
other party will be entitled to assume responsibility for such activities at its
sole expense, and such patent application or patent will become the sole
property of such party.

                14.3 Assignment. Notwithstanding the above, any Intellectual
Property developed by Diaclone at Xcyte's expense will belong solely to Xcyte
regardless of whether it would otherwise have been solely or jointly owned by
Diaclone, and Diaclone will take any action necessary to confirm Xcyte's
ownership of and assign all such Intellectual Property to Xcyte upon Xcyte's
request. Xcyte will have the exclusive right to apply for or register patents
and other proprietary protections in such assigned Intellectual Property and
Diaclone agrees to execute such documents, render such assistance and take such
other action as Xcyte may reasonably request, at Xcyte's expense, to apply for,
register, perfect, confirm and protect Xcyte's rights therein.

        15. COMMUNICATIONS AND NOTICES. All, notices hereunder will be in
writing and will be deemed given if delivered personally or by facsimile
transmission (receipt verified), telexed, or sent by express courier service to
the parties at the following addresses (or to such other address as specified by
either party):

<TABLE>
<S>                          <C>
If to Xcyte, addressed to:   Xcyte Therapies, Inc.
                             1124 Columbia Street
                             Seattle, Washington  98104
                             United States
                             Attn: Business Development
                             Fax: (206) 262-0900

With a copy to:              Venture Law Group
                             4750 Carillon Point
                             Kirkland, Washington  98033
                             United States
                             Attn: Sonya Erickson
                             Fax: (425) 739-8750

If to Diaclone:              Diaclone, S.A.
</TABLE>



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                                      -16-
<PAGE>   17

<TABLE>
<S>                          <C>
                             1 boulevard Fleming, B.P. 1985
                             F-25020 Besancon Cedex
                             France
                             Attn: Dr. John Wijdenes
                             Fax:
                                 ----------------------
</TABLE>

        16. MISCELLANEOUS.

                16.1 Assignment. This Agreement is binding on successors and
assigns of the parties provided that this Agreement may not be assigned to a
third party without the prior written consent of the other party, which consent
will not be unreasonably withheld; provided, however, that Xcyte may assign this
Agreement to an acquiror of all or substantially all of its assets or the
resulting entity in a merger or consolidation, or in connection with any other
transaction resulting in the transfer of at least fifty percent (50%) of its
voting power, without the consent of Diaclone.

                16.2 Entire Agreement. This Agreement, including the Exhibits,
Purchase Orders and, where applicable, Xcyte's Purchasing Standard Terms and
Conditions ("Ts & Cs"), constitutes the entire Agreement between the parties
regarding this subject matter and supersedes all such prior understandings
between the parties. Any amendment to this Agreement must be in writing and
signed by an authorized representative of each party. If there is any conflict
between the terms of this Agreement and the Ts & Cs or a Purchase Order, the
terms of this Agreement will prevail. If there is any conflict between the Ts &
Cs and a Purchase Order, the Purchase Order will prevail.

                16.3 Independent Contractor. Diaclone will be an independent
contractor and not an agent, partner or co-venturer of Xcyte. Neither party will
have the authority to bind the other by contract or otherwise. This Agreement
will not be deemed or construed as creating a partnership between Diaclone and
Xcyte for any purpose.

                16.4 Attorney's Fees. The prevailing party in any lawsuit or
arbitration based on or arising out of this Agreement will be entitled to
recover from the other party its costs and expenses (including attorney's fees)
reasonably incurred in connection with such lawsuit or arbitration.

                16.5 Arbitration. Any and all disputes relating to or arising
from this Agreement will be resolved by binding arbitration to be held in
Seattle, Washington under the American Arbitration Association Rules.

                16.6 No Conflict. Each party represents and warrants that it is
authorized to enter into this Agreement and that the terms of this Agreement do
not create a conflict with any right, obligation or agreement that it has with
any third party.

                16.7 Waiver. Xcyte's failure to enforce any provision of this
Agreement or a Purchase Order will not be a construed as a waiver of such
provision and will not affect Xcyte's right to enforce each and every provision
of this Agreement.



                                      -17-
<PAGE>   18

                16.8 Severability. If any term or provision of this Agreement is
held invalid or unenforceable, the remaining terms will be valid and enforced to
the fullest extent permitted by applicable law.

                16.9 Governing Law. This Agreement will be governed by and
construed in accordance with the laws of the State of Washington, USA, without
regard to its conflict of law rules, and not by the provisions of the 1980 U.N.
Convention of Contracts for the International Sale of Goods. Except as set forth
in Section 16.6, the parties hereby irrevocable submit to the jurisdiction of
the state and federal courts located in King County, Washington.

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



                                      -18-
<PAGE>   19

        IN WITNESS WHEREOF, each of the parties has caused this Agreement to be
executed by its duly authorized representative as of the date first set forth
above.



                                       DIACLONE:

                                       DIACLONE, S.A.


                                       By: /s/: John Wijdenes
                                           -------------------------------------

                                       Name: John Wijdenes
                                             -----------------------------------

                                       Title: President and CEO
                                              ----------------------------------



                                       XCYTE:

                                       XCYTE THERAPIES, INC.


                                       By: /s/: Ronald Jay Berenson
                                           -------------------------------------

                                       Name: Ronald Jay Berenson
                                             -----------------------------------

                                       Title: President and CEO
                                              ----------------------------------



                                      -19-
<PAGE>   20

                                    EXHIBIT A

                               PRODUCTION PROTOCOL

                                       [*]



*Certain information on this page has been omitted and filed
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 been requested with respect to the omitted portions.



                                      -20-
<PAGE>   21
'
                                    EXHIBIT B

                                 SPECIFICATIONS

                                       [*]




*Certain information on this page has been omitted and filed
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                                      -21-
<PAGE>   22

                                    EXHIBIT C

                             CELL LINE QUALIFICATION

                                       [*]



*Certain information on this page has been omitted and filed
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 been requested with respect to the omitted portions.




                                      -22-
<PAGE>   23

                                    EXHIBIT D

                             REGULATORY SUBMISSIONS

                                       [*]



*Certain information on this page has been omitted and filed
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                                      -23-
<PAGE>   24

                                    EXHIBIT E

                                       [*]

The following materials are to be dedicated to the manufacture of [*] antibody
for Xcyte:

[*]

TOTAL
                                                                             [*]


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                                      -24-
<PAGE>   25

                                    EXHIBIT F

                                BIOSAFETY TESTING

                                  Cell Line [*]

                                       [*]


*Certain information on this page has been omitted and filed
 separately with the Commission. Confidential treatment has
 been requested with respect to the omitted portions.



                                      -25-