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                                                                  EXECUTION COPY
                                                                   EXHIBIT 10.21

                        DEVELOPMENT AND SUPPLY AGREEMENT

        This Development and Supply Agreement (the "Agreement") is made and
entered into as of the 1st day of August, 1999 (the "EFFECTIVE DATE") by and
between XCYTE THERAPIES, INC., a Delaware corporation with offices at 1124
Columbia Street. Suite 130 Seattle, Washington 98104 (hereinafter referred to as
"XCYTE"), and DYNAL A.S., a Norwegian corporation, with offices at P.O. Box 158,
Skoyen, N-0212 Oslo, Norway (hereinafter referred to as "DYNAL").

                                   WITNESSETH:

        WHEREAS Dynal has substantial knowledge and a proprietary position and
expertise relating to research, development, manufacture and distribution of
products and technology for biomagnetic separation and handling of cells,
microorganisms, bacteria, proteins and nucleic acids;

        WHEREAS Xcyte has substantial knowledge and a proprietary position and
expertise relating to the ex vivo expansion and activation of T-cells;

        WHEREAS prior to entering into this Agreement the parties executed a
Letter Agreement dated October 27, 1999 (the "LETTER AGREEMENT") whereby Xcyte
paid Dynal the sum of one hundred thousand U.S. dollars (U.S. $100,000) in
consideration for certain development activities conducted by Dynal prior to the
Signing Date; and

        WHEREAS Dynal and Xcyte wish to establish a development and supply
agreement whereby Dynal will develop, manufacture and supply certain products
that will incorporate certain paramagnetic particles (with and without
antibodies) to be commercialized by Xcyte in one or more therapies in the Field
(as such term is defined below), as set forth in this Agreement.

        NOW, THEREFORE, in consideration of the mutual covenants and promises
contained herein, and for other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties agree as follows:

                         SECTION 1: DEFINITIONS OF TERMS

        1.1 "AFFILIATE" shall mean a person or entity that, directly or
indirectly through one or more intermediaries controls, is controlled by, or is
under common control with, a party to this Agreement. As used in this
definition, "CONTROL" means owning more than fifty percent (50%) of such an
entity or party to this Agreement.

        1.2 "ANTIBODIES" shall mean the antibodies described in the antibody
specifications set forth in Attachment A hereto. The antibody specifications set
forth in Attachment A may be modified from time to time by the mutual agreement
of the parties (including modifications as


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may be appropriate to include the release criteria for Phase III) and neither
party shall unreasonably withhold its consent to modifications proposed by the
other party.

        1.3 "ASSAYS" shall mean the assays determined mutually by the parties
(except that Xcyte shall determine the functional Assays performed and paid for
by Xcyte pursuant to Section 2.8, with Dynal's acceptance (such acceptance not
to be unreasonably withheld)) and set forth in a Work Plan to be required for
the completion of the work called for in such Work Plan, including all existing
or to-be-developed standards, specifications, validation protocols and reports
related thereto.

        1.4 "NASCENT BEADS" shall mean any beads or paramagnetic particles that
are not conjugated with antibodies or any other materials or substances or
coated with any materials or substances.

        1.5 "CD3X28 BEADS" shall mean any paramagnetic particles or beads that
are doubly conjugated with antibodies to CD3 and antibodies to CD28 and that are
not conjugated with any other antibodies.

        1.6 "cGMP" shall mean current Good Manufacturing Practices, as defined
in 21 CFR Part 210, Part 211, Part 610 and Part 680.

        1.7 "DEVELOPMENT PHASE" shall mean and refer to, as the context
indicates the period during the term of this Agreement starting on the Effective
Date and ending when Xcyte receives final marketing approval from the U.S. Food
and Drug Administration or any successor thereto (the "FDA") to use the Products
in the Field for the first indication under this Agreement.

        1.8 "DMF" shall mean a drug master file or device master file, as the
context indicates (or the non-U.S. equivalent as appropriate in each country of
the Territory) or any related regulatory filing.

        1.9 "DYNABEADS(R) M-450 CD3/CD28 T" shall mean the Dynabeads(R) M-450
CD3/CD28 beads consisting of Dynabeads(R) M-450 epoxy beads conjugated with the
Antibodies, to be developed and manufactured pursuant to this Agreement in
accordance with the Dynabeads(R) M-450 CD3/CD28 T Specifications.

        1.10 "DYNABEADS(R) M-450 EPOXY T" shall mean Dynabeads(R) M-450 epoxy
beads, to be developed and manufactured pursuant to this Agreement in accordance
with the Dynabeads(R) M-450 Epoxy T Specifications.

        1.11 "FIELD" shall mean ex vivo expansion and/or activation of T-cells
using CD3x28 Beads (whether or not in conjunction with one or more other beads,
paramagnetic particles, steps or procedures) for Therapeutic Use; provided,
however, that the Field shall exclude the following:

        [*]


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        1.12 "PATENTS" shall mean all patents and patent applications, and all
additions, divisions, continuations, continuations in-part, pipeline protection,
substitutions, reissues, extensions, registrations, patent term extensions,
supplementary protection certificates and renewals of any of the above.

        1.13 "PRODUCTS" shall mean, collectively, the Dynabeads(R) M-450 Epoxy T
and the Dynabeads(R) M-450 CD3/CD28 T.

        1.14 "SIGNING DATE" shall mean December 7, 1999, the date this Agreement
was signed by the parties.

        1.15 "SPECIFICATIONS" shall mean:

               (i) the release criteria and specifications for the Dynabeads(R)
        M-450 Epoxy T as set forth in Attachment C hereto, and as the same may
        be refined and amended from time to time by Dynal (the "DYNABEADS(R)
        M-450 EPOXY T SPECIFICATIONS"); and

               (ii) the release criteria and specifications for the Dynabeads(R)
        M-450 CD3/CD28 T as set forth in draft form in Attachment D hereto, and
        as the same may be refined, amended and finalized in the course of the
        development activities under this Agreement by the mutual agreement of
        Dynal and Xcyte (the "DYNABEADS(R) M-450 CD3/CD28 T SPECIFICATIONS").

Neither party shall unreasonably withhold its consent to an alteration or
supplementation to the Dynabeads(R) M-450 CD3/CD28 T Specifications.

        1.16 "TERRITORY" shall mean the world.

        1.17 "THERAPEUTIC USE" shall mean the attempt to cure, improve,
mitigate, treat and/or prevent disease and/or other conditions in humans.

        1.18 "THIRD PARTY" shall mean any person or entity other than a party to
this Agreement or an Affiliate of a party to this Agreement.

        1.19 "WORK PLANS" shall mean the work plans which detail the parties'
respective tasks and responsibilities with respect to the development work to be
conducted during the Development Phase in connection with the Dynabeads(R) M-450
CD3/CD28 T under this Agreement in connection with filing and obtaining final
marketing approval from the FDA in the United States as set forth in ATTACHMENT
B, and as may be amended or modified from time to time, by mutual agreement of
the parties. Subject to Section 2.5, neither party shall unreasonably withhold
its consent to amendments or modifications of the Work Plans proposed by the
other party.

        1.20 "YEAR" shall mean a calendar year.

               SECTION 2: DEVELOPMENT PHASE AND REGULATORY FILINGS



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        2.1 During the Development Phase, Dynal shall use its good faith and
commercially reasonable efforts to complete its responsibilities under the Work
Plans in accordance with the standards and time frames stated therein and the
terms and conditions of this Agreement. If Xcyte does not complete its
responsibilities under the Work Plans in accordance with the standards and time
frames stated therein and/or the terms and conditions of this Agreement, Dynal
shall not be entitled to terminate this Agreement therefor, but Dynal shall be
afforded additional time to accomplish such activity to the extent necessary to
account for any such delay caused by or as a result of actions or inactions of
Xcyte or its Affiliates or agents. [*]

        2.2 The parties shall, promptly after the Signing Date, each designate a
representative to act as a contact person for the other party and to coordinate
and communicate between the parties with respect to each party's respective
development activities under this Agreement during the Development Phase. A
party may change its designee at any time by written notice to the other party.
During the Development Phase, each party shall prepare and provide to the other
party written reports on a quarterly basis detailing its development activities
and progress under the Work Plans under this Agreement, and each party shall
also keep the other party generally updated on a monthly basis of its
development activities and progress under this Agreement.

        2.3 As part of Dynal's activities under the Work Plans, Dynal, at its
cost, shall duly file with the FDA and the regulatory agencies in the countries
included in the European Union (the "EU"), and shall own, all DMFs that are to
be filed in connection with the Products. With respect to countries in the
Territory outside of the United States and the EU, Dynal shall, at Xcyte's cost,
if and as requested by Xcyte, duly file with the regulatory agencies in such
countries, and shall own, all DMFs for the Products. During the term of this
Agreement and after the term of this Agreement upon non-renewal of this
Agreement or termination of this Agreement pursuant to Section 8.3 by Xcyte,
Xcyte shall have the right to cross-reference all DMFs filed during the term of
this Agreement by Dynal in the Territory as necessary to enable Xcyte to obtain
or maintain marketing approval for use of the Products in the Field. Xcyte or
its Antibody suppliers shall duly file with the FDA and the applicable
regulatory agencies in the Territory outside the United States and shall own all
regulatory filings for the Antibodies. [*]

        2.4 In order to fund Dynal's work directed toward the accomplishment of
the development activities under the Work Plans as well as for activities
undertaken by Dynal prior to the Signing Date, Xcyte shall make the following
non-creditable and non-refundable milestone payments to Dynal as follows:

               (i) Xcyte shall pay to Dynal five hundred thousand U.S. dollars
        (U.S. $500,000), one hundred thousand U.S. dollars (U.S. $100,000) of
        which was paid by Xcyte to Dynal prior to the Signing Date pursuant to
        the Letter Agreement, and the remaining four hundred thousand U.S.
        dollars (U.S. $400,000) of which shall be paid to Dynal on January 3,
        2000 ("MILESTONE PAYMENT 1");

               (ii) When [*] Xcyte shall pay to Dynal five hundred thousand U.S.
        dollars (U.S. $500,000) ("MILESTONE PAYMENT 2") (Dynal shall have no
        obligation to [*] prior to receiving Milestone Payment 2 from Xcyte);


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               (iii) On and as of April 1, 2000, Xcyte shall be obligated to pay
        Dynal one million U.S. dollars (U.S. $1,000,000), five hundred thousand
        U.S. dollars (U.S. $500,000) of which ("MILESTONE PAYMENT 3") shall be
        paid to Dynal on April 1, 2000 and the five hundred thousand U.S.
        dollars (U.S. $500,000) balance of which ("MILESTONE PAYMENT 4") shall
        be paid to Dynal on October 1, 2000;

               (iv) When the [*] Xcyte shall pay to Dynal five hundred thousand
        U.S. dollars (U.S. $500,000) ("MILESTONE PAYMENT 5") (Dynal shall have
        no obligation to [*] prior to receiving Milestone Payment 5 from Xcyte);
        and

               (v) When (a) the [*] (Xcyte shall notify Dynal when to commence
        the production of [*]); and (b) Dynal has [*] Xcyte shall pay to Dynal
        five hundred thousand U.S. dollars (U.S. $500,000) ("MILESTONE PAYMENT
        6") (Dynal shall have no obligation to [*] prior to receiving Milestone
        Payment 6 from Xcyte).

The milestone payments set forth in this Section 2.4 shall be paid by Xcyte by
wire transfer to an account designated by Dynal.

        2.5 Notwithstanding anything contained in this Agreement, in no event
shall Dynal be obligated to perform any activities under this Agreement that
would require efforts or expenditures in excess of the scope reasonably
contemplated by the parties as of the Signing Date, as reflected from time to
time in Work Plans, to complete the development of the Dynabeads(R) M-450
CD3/CD28 T Product during the Development Phase in connection with obtaining
marketing approval from the FDA to use the Products in the Field for the first
indication under this Agreement, and as contemplated to make the regulatory
filings pursuant to Section 2.3.

        2.6 [*] Except as otherwise expressly set forth in this Agreement,
including Sections 2.3 and 6, Xcyte shall own all clinical protocols, all
results of such clinical tests, all other clinical data required for regulatory
submissions and approvals, all such regulatory filings, and any and all
regulatory approvals.

        2.7 Dynal shall inform Xcyte of any amendments to the Dynabeads(R) M-450
Epoxy T Specifications.

        2.8 Xcyte shall own any and all proprietary rights relating to the
functional Assays, provided that Xcyte shall develop the functional Assays
(including the inter-lab validation of the functional Assays) and shall pay for
all costs and expenses associated therewith.

                       SECTION 3: SUPPLY AND DISTRIBUTION

        3.1 During the term of this Agreement, and subject to the terms and
conditions set forth herein, (a) Xcyte shall, as ordered by Dynal, supply Dynal
with the Antibodies, at Xcyte's cost, for use by Dynal solely for use in the
production of the Dynabeads(R) M-450 CD3/CD28 T in accordance with the
specifications for the Antibodies set forth in Attachment A and the
Specifications; and (b) Dynal, subject to Xcyte's obligation to supply
Antibodies to Dynal, shall supply to Xcyte, and Xcyte shall purchase from Dynal,
all of Xcyte's and its Affiliates'


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requirements (i) for Dynabeads(R) M-450 CD3/CD28 T for use in clinical trials
and other product research, development, certification or regulatory activities
conducted in connection with either or both of the Products in the Field in the
Territory; and (ii) for Dynabeads(R) M-450 CD3/CD28 T for use, marketing,
distribution, sale and import by Xcyte and its Affiliates in the Field in the
Territory; and (iii) to be held in reasonable inventories associated with any of
the foregoing.

        3.2 During the term of this Agreement, Dynal shall supply to Xcyte, and
Xcyte shall purchase from Dynal, all of Xcyte's and its Affiliates' requirements
(a) for Dynabeads(R) M-450 Epoxy T for use in clinical trials and other product
research, development, certification or regulatory activities conducted in
connection with either or both of the Products in connection with the
Dynabeads(R) M-450 CD3/CD28 T in the Field in the Territory; (b) for
Dynabeads(R) M450 Epoxy T for use, marketing, distribution, sale, and import by
Xcyte and its Affiliates in connection with the Dynabeads(R) M-450 CD3/CD28 T in
the Field in the Territory; and (c) to be held in reasonable inventories
associated with any of the foregoing. For the avoidance of doubt, to the extent
that Dynal has to conduct any development activities with respect to the
Dynabeads(R) M-450 Epoxy T, Dynal shall ensure that it conducts such activities
in a timely manner so that it will be able to supply Xcyte the Dynabeads(R)
M-450 Epoxy T Product when it supplies Xcyte the Dynabeads(R) M-450 CD3/CD28 T
Product, as provided under this Agreement.

        3.3 Xcyte shall ensure that any Products to be sold or otherwise
distributed by Xcyte or its Affiliates or any of their distributors, licensees
or agents, for use in the Field shall be appropriately labeled to state that the
use thereof is limited to use solely within the Field. If either party becomes
aware that Products are being used outside the Field or outside the Territory,
it shall promptly notify the other party hereto. Xcyte shall and shall ensure
that its Affiliates and each of their distributors, licensees and agents shall,
use its reasonable commercial efforts to preserve the quality of the Products
and shall act in accordance with any applicable quality control guidelines for
the Products provided to Xcyte by Dynal.

        3.4 Xcyte shall not, and shall ensure that its Affiliates and that their
respective distributors, licensees and agents shall not, sell or use any
Products or perform any treatments utilizing the Products not in compliance with
applicable laws, regulations and orders. If either party becomes aware that
Products are being used, or that treatments are being performed using the
Products, not in compliance with applicable laws, regulations and orders, it
shall promptly notify the other party hereto.

        3.5 Xcyte shall, and shall ensure that its Affiliates and/or its and its
Affiliates' distributors, licensees and agents shall, only sell and distribute
the Products for use in the Field in the Territory pursuant to the terms and
conditions of this Agreement, and in doing so neither Xcyte nor its Affiliates
shall use or sell or otherwise distribute, and shall ensure that their
respective distributors, licensees and agents shall not use or sell or otherwise
distribute, the Dynabeads(R) M-450 Epoxy T for any use except in connection with
the Dynabeads(R) M-450 CD3/CD28 T and only in the Field. Xcyte shall remain
primarily liable and responsible for the performance and observance of all of
its and its Affiliates' and each of their consultants,



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distributors' and licensees' and agents' duties and obligations in accordance
with the terms and conditions of this Agreement. Any agreement between Xcyte and
any of its Affiliates or any of their consultants, distributors, licensees or
agents shall be consistent with the terms and conditions of this Agreement and
shall include appropriate obligations of confidentiality and a limitation to use
of the Products solely within the Field.

        3.6 During the term of this Agreement, Xcyte shall purchase all of its
requirements for CD3x28 Beads and Nascent Beads for use in the Field; however,
if Xcyte must substitute another CD3x28 Bead for the Dynabeads(R) M-450 CD3/CD28
T and/or another Nascent Bead for the Dynabeads(R) M-450 Epoxy T for medical
(e.g., adverse medical reaction arising from use of the Dynabeads(R) M-450
CD3/CD28 T Product and/or the Dynabeads(R) M-450 Epoxy T Product) or regulatory
(e.g., rejection of the Dynabeads(R) M-450 CD3/CD28 T Product and/or the
Dynabeads(R) M-450 Epoxy T Product by a regulatory agency) reasons for use in
the Field in any country or countries of the Territory, Xcyte shall promptly
notify Dynal and provide Dynal with sufficient information and documentation to
evidence the medical and/or regulatory reason or reasons that require Xcyte to
substitute the Dynabeads(R) M-450 CD3/CD28 I Product and/or the Dynabeads(R)
M-450 Epoxy T Product. After such notice and provision of information and
documentation have been provided to Dynal by Xcyte, the parties shall discuss in
good faith what would be an acceptable substitute CD3x28 Bead and/or substitute
Nascent Bead, and after the parties mutually identify, or a party identifies, in
writing, an acceptable substitute, unless Dynal notifies Xcyte in writing that
it does not wish (as determined by Dynal in its sole discretion) to supply Xcyte
with the substitute CD3x28 Bead and/or substitute Nascent Bead, the parties
shall negotiate in good faith the terms and conditions of a development and/or
supply agreement for the substitute CD3x28 Bead and/or substitute Nascent Bead
for such country or countries upon commercially reasonable terms and conditions
(subject to the limitations on Dynal's obligations set forth in Section 2.5). If
the parties do not execute a full agreement which covers such development and/or
supply arrangement within one hundred and twenty (120) days of commencing such
good faith negotiations, Xcyte may obtain the substitute CD3x28 Bead and/or the
substitute Nascent Bead from a Third Party; provided that Xcyte may not offer
terms or conditions to any such Third Party which are more favorable in the
aggregate to those offered to Dynal hereunder, unless such new terms and
conditions have first been offered to Dynal and Dynal has not accepted such
terms and conditions (or terms and conditions substantially similar thereto) in
writing within sixty (60) days of such offer by Xcyte. If Dynal notifies Xcyte
in writing at any time during the discussions or negotiations set forth in this
Section above that it does not wish to supply Xcyte with the substitute CD3x28
Bead and/or substitute Nascent Bead as provided in this Section above, Xcyte may
obtain the substitute CD3x28 Bead and/or the substitute Nascent Bead from a
Third Party.

        3.7 In the event that Xcyte plans to acquire, use, develop, sell or
distribute any beads or paramagnetic particles (other than the Products, CD3x28
Beads and Nascent Beads) for use in the Field in addition to either or both of
the Products, Xcyte shall promptly notify Dynal detailing the beads or
paramagnetic particles that Xcyte requires and thereafter the parties shall in
good faith attempt to negotiate the terms and conditions of a development and/or
supply agreement for such beads and/or paramagnetic particles for the Territory.
If the parties do not



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execute an agreement which covers such development and/or supply arrangement
within ninety (90) days of commencing such good faith negotiations, Xcyte may
obtain such beads or paramagnetic particles from a Third Party.

        3.8 Notwithstanding anything contained in this Agreement, if Xcyte
undergoes a change of control during the Development Phase, such that Xcyte is
directly or indirectly controlled by any person or entity that derives at least
fifty percent (50%) of its revenue from the development and/or manufacture of
beads and/or paramagnetic particles, Xcyte hereby agrees that it shall not, and
hereby agrees to ensure that any such person or entity shall not, until the
non-renewal of this Agreement or three (3) years after such change of control
(whichever occurs first), disclose to such person or entity any information
relating to the Products, or supply any Products to such person or entity.
Notwithstanding anything contained in this Agreement, both during and after the
term of this Agreement, such person or entity shall be treated as a Third Party
for all purposes of this Agreement, regardless of whether such person or entity
may be an "Affiliate" of Xcyte after such change of control. As used in this
clause, "CHANGE OF CONTROL" means any event (whether in one or more
transactions) which results in a transfer of direct or indirect ownership of
more than fifty percent (50%) of the voting stock of Xcyte to a previously
unaffiliated third party.

        3.9 For the avoidance of doubt and without limiting either party's
development and supply obligations under this Agreement, in no event shall this
Agreement restrict: [*]

                     SECTION 4: PRICE, PAYMENT AND DELIVERY

        4.1 Dynal shall supply to Xcyte reasonable quantities of samples of the
Dynabeads(R) M-450 Epoxy T and of the Dynabeads(R) M-450 CD3/CD28 T, in
quantities and supply schedules as are more fully described in the Work Plans
for use by Xcyte and Xcyte's consultants during the Development Phase. During
the Development Phase and prior to the point at which the Products being
supplied will be used in Phase I clinical trials, the Products shall be provided
by Dynal without charge to Xcyte.

        4.2 Starting at the point during the Development Phase at which the
Products being supplied to Xcyte by Dynal will be used in Phase I clinical
trials, the initial price of Products sold to Xcyte shall be the applicable
price set forth on Attachment E hereto (regardless of the concentration of beads
in each vial, which concentration shall be determined by Xcyte, provided that no
such concentration shall be in excess of 4 x 108 beads/ml in a 10 ml vial). All
such prices are quoted FCA, Oslo, Norway (Incoterms 1990). Such prices shall not
be increased until [*] and thereafter, Dynal may raise such prices no more often
than [*] Anything in this Section 4.2 to the contrary notwithstanding, no annual
increase shall have the effect of raising the previous year's price by [*]

        4.3 Dynal shall deliver the Products ordered by Xcyte pursuant to this
Agreement to Xcyte, FCA Oslo, Norway (Incoterms 1990). Risk of loss shall pass
to Xcyte on delivery of the Products to the carrier selected by Xcyte. Dynal
shall include the information as described in Attachment F with each shipment of
the Products. Upon delivery of the Products to Xcyte's

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carrier, Dynal shall invoice Xcyte, and Xcyte shall make payment to Dynal within
thirty (30) days from the date of the invoice. Upon request by Xcyte, Dynal
shall transmit invoices by facsimile or by any other means mutually agreed to by
the parties. Notwithstanding the foregoing, or anything contained in this
Agreement, with respect to Dynabeads(R) M-450 CD3/CD28 T Product ordered by
Xcyte and delivered to Xcyte hereunder that is part of a batch of the
Dynabeads(R) M-450 CD3/CD28 T produced by Dynal for Phase I clinical trials
and/or other development work to be performed during such period of the
Development Phase, Xcyte may make payment to Dynal for such Dynabeads(R) M-450
CD3/CD28 T Product so ordered by Xcyte within twelve (12) months (instead of
thirty (30) days) from the date of the invoices for such Product.

        4.4 Xcyte shall pay interest to Dynal on any overdue payments under this
Agreement at a rate of [*] per month overdue from the date due until payment.

        4.5 Dynal reserves the right to alter the payment procedures set forth
in this Agreement in the event that Xcyte has previously (within the then-most
recent three-month period) failed to conform to the payment provisions hereof
and if and for so long as Dynal is reasonably concerned about Xcyte's financial
condition. Such alterations in payment terms shall be either a requirement of an
irrevocable, confirmed letter of credit or a requirement of cash prior to
delivery.

        4.6 Xcyte shall not require a delivery date of earlier than ninety (90)
days after the date of receipt of an order for Products by Dynal. Orders by
Xcyte for Products shall be sent to Dynal at P.O. Box 158, Skoyen N-0212, Oslo,
Norway, or as otherwise may be directed by Dynal from time to time. Dynal shall
use its reasonable efforts to fill orders from Xcyte which are in accordance
with this Section 4 by the delivery date requested by Xcyte. Dynal shall
acknowledge each Xcyte purchase order in writing and notify Xcyte of the
estimated delivery date. Dynal shall promptly notify Xcyte if at any time Dynal
has reason to be concerned that Dynal will not be able to fill any Xcyte order
on time or as estimated or agreed.

        4.7 Xcyte shall, starting at the thirtieth (30th) day following the end
of the Development Phase and thereafter on a quarterly basis (by March 31st,
June 30th, September 30th, and December 31st) of each Year, provide to Dynal a
forecast of Xcyte's requirements for the Products for the ensuing twelve (12)
month period for the Territory. The amount of Products specified for the first
quarter of such twelve (12) month period shall be binding on Xcyte, and Dynal
shall supply, and Xcyte shall be required to take delivery and pay for such
amount of the Products. All amounts specified for succeeding quarters of a
twelve (12) month period are considered a non-binding but good faith forecast.

        4.8 In addition to the forecasts provided pursuant to Section 4.7, Xcyte
shall provide to Dynal good faith non-binding three (3) Year forecasts for the
Products for capacity and long-term manufacturing planning purposes. This three
(3) Year forecast shall be provided by Xcyte to Dynal on or before the thirtieth
(30th) day following the end of the Development Phase, and thereafter by August
31st of each Year, covering the succeeding three-Year period. In the event

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that the manufacture of the volumes of Dynabeads(R) M-450 CD3/CD28 T indicated
by such three-Year forecast would require Dynal to make any capital expansions
(including entering into any leases), the parties may meet to discuss in good
faith how to proceed and whether Xcyte would be willing to commit to such
forecasts if Dynal decides to make any capital expansion and/or enter into any
leases (as Dynal shall decide in its sole discretion). Subject to the provisions
of Section 4.10, in no event shall Dynal be required to meet any such forecast
for the Dynabeads(R) M-450 CD3/CD28 T (beyond the levels stated therein that
would not require Dynal to make such capital expansions) nor to obtain such
capital expansions unless the parties agree in writing how to proceed and
without Xcyte agreeing to purchase sufficient volumes of the Products and to
amend this Agreement to increase the minimums set forth in Section 8.5.

        4.9 All sales of Products to Xcyte shall be controlled by the terms and
conditions of this Agreement and the standard terms and conditions of the
business forms of the parties shall not form part of the agreement of the
parties.

        4.10 During the term of this Agreement, Dynal shall notwithstanding
Section 4.8, fill any order (or series of orders) for any calendar quarter which
are in accordance with this Article 4 and that is (or are) not in excess of one
hundred twenty five percent (125%) of the volumes specified for such calendar
quarter in Xcyte's most recent good faith quarterly estimate for such calendar
quarter (i.e., that was not a binding order for such calendar quarter under
Section 4.7), and Dynal shall not be required to fill any order or series of
orders that are for any calendar quarter in excess of one hundred twenty five
percent (125%) of the volumes specified for such calendar in Xcyte's most recent
good faith quarterly estimate for such calendar quarter. However, Dynal shall
nevertheless exert commercially reasonable efforts to fill all Xcyte orders and
to supply all requested volumes to the extent the same may be done without extra
cost to Dynal, and in doing so Dynal would not be in violation of any other
agreement.

        4.11 Notwithstanding anything contained herein, in no event shall Dynal
be liable for any delay or failure to deliver Products for reasons beyond the
control of Dynal, provided, however, that Dynal shall notify Xcyte promptly of
anticipated delays and shall use all commercially reasonable efforts to fill
such orders as soon as possible.

        4.12 If Dynal is not able to manufacture the Products in the quantities
ordered by Xcyte in accordance with the terms and conditions of this Agreement
either itself or through its Affiliates, Dynal shall undertake to engage and
qualify a Third Party contract manufacturer to manufacture those quantities of
the Products that Dynal and/or its Affiliates are unable to supply to Xcyte, for
supply to Xcyte subject to and in accordance with the terms and conditions of
this Agreement (including the terms and conditions of this Agreement relating to
Specifications, quality control and assurance, price, ordering, delivery,
indemnities and warranties) and Xcyte shall continue to pay Dynal for the
Products in accordance with Section 4. The parties recognize that use of such a
Third Party contract manufacturer would constitute a "Major Change" as such term
defined in Attachment F, and that it will be handled in accordance with and
shall be governed by the requirements in that Attachment.



                                      -10-
<PAGE>   11

        4.13 All payments due to Dynal under this Agreement shall be paid in
full, regardless of whether Xcyte or its Affiliates or their distributors or
licensees are required to withhold taxes, levies or other duties on payments
made under this Agreement. If Xcyte is required to withhold taxes, levies or
other duties on payments made under this Agreement, then Xcyte shall gross up
such payments so that Dynal receives the payment in full regardless of any
withholdings, and if Dynal obtains any credit for the amount of the withholding,
such amount shall be repaid by Dynal to Xcyte when it is received by Dynal.

                       SECTION 5: WARRANTY AND DISCLAIMER

        5.1 Dynal warrants that the Products shall conform to the Specifications
upon delivery to Xcyte's carrier, provided that in no event shall Dynal be
responsible or liable for any failure of the Products to meet the Specifications
as a result of defects in the Antibodies (other than any defect in the
Antibodies caused solely because of a failure of Dynal or its Affiliates to act
in conformity with any applicable quality control guidelines provided to Dynal
by Xcyte). Xcyte shall promptly inspect the Products upon receipt and in
accordance with any applicable quality control guidelines provided to Xcyte by
Dynal, and shall promptly notify Dynal of any discovered failure of the Products
to conform to the Specifications, but in no event later than thirty (30) days
after Xcyte's receipt of the Products. Upon request by Dynal, Xcyte shall
promptly return the non-conforming Products to Dynal. Upon verification that the
Products failed to comply with the Specifications upon delivery to Xcyte's
carrier other than because of defects in the Antibodies (other than any defect
in the Antibodies caused solely because of a failure of Dynal or its Affiliates
to act in conformity with any applicable quality control guidelines provided to
Dynal by Xcyte), Xcyte shall receive, at Dynal's sole option, a credit, refund
or replacement for such non-conforming Products. In the event that Dynal decides
to replace such non-conforming Products with conforming Products, Dynal shall
use reasonable commercial efforts to do so within sixty (60) days of such
confirmation by Dynal, and Dynal shall in such event bear the cost of delivery
and risk of loss or damage to the replacement Products during delivery.
Notwithstanding anything to the contrary contained in this Agreement, Dynal
shall not be responsible for any Products if such Products are removed from
their original vials prior to inspection by Xcyte or are modified in any manner
not in conformity with any applicable quality control guidelines provided to
Xcyte by Dynal, nor for any use or misuse or actions or inactions by any person
or entity after delivery of the Products to Xcyte's carrier.

THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
AND DYNAL EXPRESSLY DISCLAIMS ANY IMPLIED WARRANTIES INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. EXCEPT AS SET FORTH IN SECTION 10, XCYTE'S EXCLUSIVE REMEDY
FOR ANY DEFECT IN THE PRODUCTS OR BREACH OF WARRANTY SHALL AT DYNAL'S OPTION BE
CREDIT, REFUND OR REPLACEMENT AS SET FORTH IN THIS SECTION 5. EXCEPT AS SET
FORTH IN SECTION 10, IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY SPECIAL,
CONSEQUENTIAL OR INCIDENTAL DAMAGES BASED



                                      -11-
<PAGE>   12

UPON BREACH OF WARRANTY, BREACH OF CONTRACT, NEGLIGENCE, STRICT TORT OR ANY
OTHER LEGAL THEORY.

                        SECTION 6: INTELLECTUAL PROPERTY

        6.1 Except as provided in Section 6.2, ownership of any and all
inventions or other proprietary rights ("Inventions") developed in connection
with activities under or performed in connection with this Agreement, including
in connection with development and acceptance testing of the Dynabeads(R) M-450
Epoxy T and the Dynabeads(R) M-450 CD3/CD28 T or during or in connection with
work performed under the Work Plans, shall be determined by reference to United
States laws pertaining to inventorship. For example, (a) if Inventions is
developed in connection with the development activities hereunder by one (1) or
more employees or consultants of each party, it shall be jointly owned ("Joint
Inventions"), and if one (1) or more claims included in an issued Patent or
pending Patent application which is filed in a patent office in the Territory
claim such Joint Inventions such claims shall be jointly owned ("Joint Patent
Rights"); and (b) if Inventions is developed in connection with development
activities hereunder solely by an employee or consultant of a party, it shall be
solely owned by such party, and any Patent filed claiming such solely owned
Inventions shall also be solely owned by such party. Each party shall ensure
that its employee and consultant inventors of Inventions developed in connection
with this Agreement shall assign his/her interest in such Inventions to his/her
respective party employer (e.g., Dynal or Xcyte, as the case may be), and such
rights shall therefore vest in the respective party employer to whom the
inventor assigns his/her rights. The parties shall discuss and consult with each
other in good faith as to the filing and prosecution of any joint patent
applications covering Joint Inventions, the maintenance of any ensuing Joint
Patent Rights covering such Joint Inventions, and the enforcement, defense and
protection of any such Joint Patent Rights.

        6.2 Notwithstanding anything contained in this Agreement, including
Section 6.1: (a) any Inventions, including any know-how and data relating to any
Dynabeads(R), including the Dynabeads(R) M-450 and/or coupling to Dynabeads(R)
and/or the coating of Dynabeads(R), shall be owned solely by Dynal regardless of
inventorship and Xcyte shall assign any and all such rights that Xcyte and/or
its Affiliates or any of their agents may have in or to any such Inventions to
Dynal, and such rights shall therefore vest in Dynal; and (b) any Inventions,
including any know-how and data relating to the Antibodies shall be owned solely
by Xcyte regardless of inventorship and Dynal shall assign any and all such
rights that Dynal and/or its Affiliates or any of their agents may have in or to
any such Inventions to Xcyte, and such rights shall therefore vest in Xcyte.

        6.3 This Agreement contains no grants to either party under any
intellectual property of the other party, except as expressly set forth in this
Agreement.

        6.4 Xcyte retains all right, title and interest in and to the Antibodies
delivered or to be delivered to Dynal hereunder. Unless otherwise agreed by the
parties, Dynal shall not at any time during the term of this Agreement, divert
or use any of the Antibodies for any other purpose or in



                                      -12-
<PAGE>   13

support of any other product or service than the Dynabeads(R) M-450 CD3/CD28 T
to be developed and manufactured hereunder solely for supply to Xcyte, and Dynal
shall not authorize anyone else to do so.

                  SECTION 7: TRADEMARK, LABELING AND PACKAGING

        7.1 Xcyte shall use the registered trademark "Dynabeads(R)" in the
package inserts, labels and packaging and, to the extent appropriate, promotion
and marketing materials, used in connection with the sale of the Products or the
performance of the treatments using the Products, and each such package insert,
label and packing and promotion and marketing materials that uses such trademark
shall state: "Dynabeads(R) is a registered trademark of Dynal A.S., Oslo Norway,
licensed to Xcyte" or equivalent language approved by Dynal. Xcyte and Dynal
shall cooperate reasonably in the use by Xcyte of Dynal's trademark, so that
such use will be consistent with applicable regulations, including any
concerning or affecting the designation of Xcyte as the manufacturer. Subject to
the terms and conditions of this Agreement, during the term of this Agreement,
Dynal hereby grants to Xcyte a non-exclusive license to use the Dynabeads(R)
trademark to such limited extent. The registered trademark "Dynabeads(R)" is and
shall remain the sole and exclusive property of Dynal and all goodwill arising
from the use of the Dynabeads(R) trademark shall enure to the benefit of Dynal.
If necessary in any market to maintain Dynal's rights in Dynal's trademarks,
Xcyte shall enter into a reasonable separate royalty-free license or registered
user agreement regulating its use of the Dynal trademarks. Approval of such
material by Dynal shall not be unreasonably withheld. Approval shall be deemed
given in the event that Dynal does not otherwise so notify Xcyte within
twenty-one (21) days after receipt of such material from Xcyte. During any
periods in which Xcyte is so using any Dynal trademark(s), Xcyte shall
periodically and upon reasonable request, provide Dynal with samples of any
products and packages that bear, or that have been associated with, copies of
all product literature, promotional material, advertising, product inserts,
labeling and packaging and other printed materials that use, the "Dynabeads(R)"
trademark, in order that Dynal may monitor the quality of products associated
with such trademark(s).

        7.2 The Products shall be labeled and packaged for delivery to Xcyte as
provided in Attachment F.

                         SECTION 8: TERM AND TERMINATION

        8.1 This Agreement shall come into effect on the Effective Date and
unless terminated earlier as provided herein shall continue for a period often
(10) years. Either party shall have the option to extend the term of this
Agreement for an additional five (5) years after the initial ten (10) year term,
by written notice to the other at any time at least one hundred and eighty (180)
days prior to the end of the initial ten (10) year term. Following the end of
the initial ten (10) year term (if it is not so renewed for an additional five
(5) years), or the end of such five (5) year renewal term (if the ten (10) year
initial term is so renewed), this Agreement shall be automatically renewed for
successive one (1) year terms unless either party gives the other party



                                      -13-
<PAGE>   14

written notice of termination of the term at least ninety (90) days prior to the
conclusion of the then-current term, to be effective at the end of such current
term.

        8.2 This Agreement may be terminated by either party upon the happening
of any of the following events:

            (i) if the other party shall generally cease to pay debts as they
come due; or

            (ii) if the other party shall cease to do business, enter into
liquidation, or become subject to any bankruptcy law or enter into any agreement
with its creditors or commit any similar act.

        8.3 If either party shall fail to perform its material obligations under
this Agreement, the other party shall have the right to terminate this Agreement
upon ninety (90) days written notice to the defaulting party, provided, however,
that if:

            (i) such default is cured within the notice period, this Agreement
shall not be terminated therefor; or

            (ii) such failure is a failure by Dynal to accomplish an activity
under the Work Plans or an obligation under this Agreement that is the
responsibility of Dynal, within the time frame established in the applicable
Work Plan or otherwise under this Agreement for such accomplishment or
obligation, Dynal shall be afforded additional time to accomplish such activity
to the extent necessary to account for any factors beyond its reasonable control
(such as, without limitation, as a result of any action or inaction of the FDA)
or as a result of any delay caused by or as a result of actions or inactions of
Xcyte or its Affiliates or agents.

        8.4 Either party may terminate this Agreement upon written notice to the
other party at any time prior to the first filing by Xcyte with the FDA for a
marketing approval of the treatments and/or products utilizing the Products in
the Field, if the parties mutually agree in writing that the Products cannot,
for scientific, regulatory or technical reasons not due to a breach hereof by
the party seeking such a termination, be developed and certified for commercial
use in the Field. Neither party shall unreasonably withhold its consent to any
such mutual agreement.

        8.5 Dynal may terminate this Agreement upon at least one hundred and
eighty (180) days advance written notice to Xcyte:

            (i) if Xcyte does not order from Dynal at least [*] of Dynabeads(R)
M-450 CD3/CD28 T (measured by the [*] pursuant to Section 4.2) prior to end of
the first twelve-month period following the [*] and Dynal gives Xcyte its notice
of such termination no later than sixty (60) days following the end of such
twelve (12) month period; or

            (ii) if Xcyte does not order from Dynal at least [*] pursuant to
Section 4.2) in any twelve (12) month period that begins after the end of the
first twelve-month period described


*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.


                                      -14-
<PAGE>   15

above in clause (i) of this section and Dynal gives its notice of such
termination no later than sixty (60) days following the end of such twelve (12)
month period.

        8.6 No termination or non-renewal of this Agreement shall extinguish any
right or obligation that has accrued prior thereto, or that is a
post-termination or post-non-renewal right or obligation under the terms and
conditions of this Agreement, including those set forth in Section 11. Upon
termination or non-renewal of this Agreement:

            (i) Xcyte shall cease all use of Dynal's trademarks and other
intellectual property rights and shall cooperate with Dynal in terminating any
separate license or registered user agreement or recordal thereof; except that
upon non-renewal of this Agreement or termination of this Agreement pursuant to
Section 8.3 by Xcyte, Xcyte may continue to use the Dynabeads(R) trademark,
subject to the terms and conditions of this Agreement, until the occurrence of
the earlier of: (a) receipt by Xcyte of all applicable regulatory approvals to
alter labeling, packaging, and promotional materials (which regulatory approvals
Xcyte shall use reasonably commercial efforts to obtain as soon as possible
after any such non-renewal or termination of this Agreement), and (b) one (1)
year after such non-renewal or termination, and thereafter Xcyte shall cease all
use of Dynal's trademarks and other intellectual property rights and shall
cooperate with Dynal in terminating any separate license or registered user
agreement or recordal thereof

            (ii) all sums accrued hereunder prior to such termination or
non-renewal shall become immediately due and payable; and

            (iii) Xcyte shall continue after such termination or non-renewal to
have the right to cross-reference the DMFs as provided in Section 2.3.

                          SECTION 9: QUALITY ASSURANCE

        9.1 Certain obligations and responsibilities of Dynal and Xcyte with
respect to the manufacture and quality control analysis of the Products under
the Agreement shall be set forth in the applicable quality assurance guidelines
set forth in Attachment F.

        9.2 Certain obligations and responsibilities of Dynal and Xcyte with
respect to the manufacture and quality control analysis of the Antibodies under
the Agreement shall be set forth in the applicable quality assurance guidelines
set forth in Attachment G.

              SECTION 10: WARRANTIES; INDEMNIFICATION'S; INSURANCE

        10.1 Each of Xcyte and Dynal represents and warrants to the other that:

            (i) it has the full right, power and authority to enter into and
perform this Agreement;



                                      -15-
<PAGE>   16

            (ii) the execution and performance of this Agreement by it does not
and will not violate any law or regulation, or any agreement to which it is a
party or by which it is bound;

            (iii) when executed and delivered, this Agreement will constitute
the legal, valid and binding obligation of such party, enforceable against it in
accordance with its terms; and

            (iv) it has obtained, and shall at all times during the term of this
Agreement hold and comply with, all licenses, permits and authorizations
necessary to perform this Agreement as now or hereafter required under any
applicable statutes, laws, ordinances, rules and regulations of the United
States and any applicable foreign, state, and local governments and governmental
entities.

        10.2 Dynal hereby indemnifies and agrees to defend and to hold Xcyte,
its successors and its Affiliates and each of their employees, directors,
officers and agents harmless from and against all Third Party claims,
liabilities, losses and expenses (other than lost profits) (including reasonable
attorneys' fees) arising out of:

            (i) the failure of the Products to meet the warranty set forth in
Section 5; provided that in no event shall Dynal be responsible or liable for
any failure of the Products to meet the Specifications as a result of: (a)
defects in the Antibodies (other than any defect in the Antibodies caused solely
because of a failure of Dynal or its Affiliates to act in conformity with any
applicable quality control guidelines provided to Dynal by Xcyte) or (b) actions
or inactions by any person or entity after delivery of the Products to Xcyte;

            (ii) any Third Party claims for infringement or misappropriation of
any intellectual property rights based on the method of manufacture or
composition of the Dynabeads(R) included in the Product (but not for any other
claims for infringement or misappropriation based on the use or sale of
Dynabeads(R) or the Products, for which Xcyte shall indemnify and defend Dynal,
its successors and its Affiliates and each of their employees, directors,
officers and agents pursuant to Section 10.3) or

            (iii) any breach or inaccuracy of any of Dynal's representations or
warranties made herein.

        10.3 Xcyte hereby indemnifies and agrees to defend and to hold Dynal,
its successors and its Affiliates and each of their employees, directors,
officers and agents harmless from and against all Third Party claims,
liabilities, losses and expenses (other than lost profits) (including reasonable
attorneys' fees) arising out of:

            (i) the development, use, promotion, marketing, manufacture,
distribution, sale or import of any of the Products and performance of
treatments using any of the Products, including any actual or alleged
infringement or misappropriation of any Intellectual Property of any Third
Party, except for any Third Party claims expressly covered by Dynal's
indemnification of Xcyte pursuant to Section 10.2 or



                                      -16-
<PAGE>   17

            (ii) any breach or inaccuracy of any of Xcyte's representations or
warranties made herein.

        10.4 Each party shall communicate to the other notice of all claims
falling within the indemnity provided by the other pursuant to Sections 10.2 and
10.3, as soon as possible after their receipt. The indemnified party shall
cooperate fully with the indemnifying party in defending or otherwise resolving
such claims. The indemnifying party shall have full control of the defense and
settlement of all litigation brought against the indemnified party arising out
of such claims, provided that any settlement or voluntary consent judgment shall
require the consent of the indemnified party, such consent not to be
unreasonably withheld. The indemnified party, at its expense, shall be entitled
to participate in such defense through its own counsel, subject to the retention
of control of such defense by the indemnifying party.

        10.5 Each party shall obtain and keep in force during the term of this
Agreement, and for a period of three (3) years after the non-renewal or
termination of this Agreement, comprehensive general liability insurance
covering bodily injury and property damage in amounts of not less than [*] per
year combined single limit; covering completed operations liability and
contractual liability in amounts of not less than [*] and, [*] Each party shall
provide written proof of the existence of such insurance to the other party upon
request.

                 SECTION 11: CONFIDENTIALITY AND PRESS RELEASES

        11.1 It is understood by both Dynal and Xcyte that misuse or disclosure
of Confidential Information of the other party could irreparably harm the
business of the disclosing party or that party's Affiliates. As used herein,
"Confidential Information" shall mean, subject to the exceptions set forth in
Section 11.2, all confidential and proprietary information (including all other
technology, know-how, data and records, whether written or oral or obtained
through inspection of facilities or samples), which is obtained by a receiving
party (Xcyte or Dynal, as the case may be) from a disclosing party (Xcyte or
Dynal, as the case may be), where either it is identified by the disclosing
party as being confidential at the time of disclosure or the circumstances of
disclosure otherwise reasonably put the recipient on notice that the information
or materials are treated as confidential or which receiving party should
reasonably know should be treated as confidential. The parties agree:

            (i) not to use such Confidential Information for any purpose other
than for the purpose of this Agreement or as may otherwise be agreed by the
parties in writing;

            (ii) to use the same degree of care to maintain such Confidential
Information in confidence as it applies to confidential information of its own
of the same type, but in no event less than a reasonable standard of care, and
not to disclose any portion of such Confidential Information to any person or
entity other than as needed for the purposes of this Agreement;

            (iii) to cause its Affiliates and each of its and its Affiliates'
employees, Affiliates, licensees and consultants (and the employees of any
thereof) who are to be given


*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.

                                      -17-
<PAGE>   18

access to such Confidential Information to agree to be bound by the provisions
of this Section 11 or by other provisions at least as protective as those set
forth in this Section 11.

        11.2 The provisions of this Section 11 shall not apply to:

            (i) Information that can be demonstrated by the receiving party by
credible evidence to be in the public domain at the time of disclosure.

            (ii) Information that, after disclosure, can be demonstrated by the
receiving party by credible evidence to have subsequently become part of the
public domain other than as a consequence of a breach of this Agreement by the
receiving party or its employees or agents.

            (iii) Information that can be demonstrated by the receiving party by
credible evidence to have been known or otherwise available to the receiving
party prior to the disclosure by the disclosing party.

            (iv) Information that, after disclosure, can be demonstrated by the
receiving party by credible evidence to have been subsequently provided to the
receiving party by a Third Party having the right to disclose such information
and without obligations of confidentiality if the receiving party reasonably
believes such disclosure does not violate any obligations of the Third Party to
the disclosing party.

            (v) Information that has been independently developed without the
benefit of any reference to any disclosure hereunder from the other party.

            (vi) Information that is required to be disclosed by law or
regulation, provided that the party required to make such disclosure shall, to
the extent practicable under such law or regulation and the circumstances, give
the other party prior notice of such requirement and afford it an opportunity to
seek restrictions or limitations on such disclosure.

        11.3 Upon non-renewal or termination of this Agreement. the receiving
party shall, upon the disclosing party's written request, promptly return to the
disclosing party, all copies of Confidential Information received from the
disclosing party, and shall return or destroy, and document the destruction of,
all summaries, abstracts, extracts or other documents that contain any
Confidential Information of the disclosing Party; except that the receiving
party may retain copies of Confidential Information (including summaries,
abstracts, extracts or other documents that contain any Confidential
Information) received from the disclosing party if the retention of the same is
necessary for regulatory purposes or is otherwise required by law or regulation,
and in any event the receiving party may retain one (1) copy of Confidential
Information received from the disclosing party for archival purposes.

        11.4 The provisions of this Section 11 shall not terminate upon
non-renewal or termination of this Agreement, but shall continue for a period of
seven (7) years following the termination or non-renewal of this Agreement.



                                      -18-
<PAGE>   19

        11.5 Unless otherwise agreed by the parties, the parties agree to issue,
within thirty (30) days from the Signing Date, a mutually agreed upon press
release. Neither party to this Agreement shall otherwise issue any press release
or other publicity materials, or make any public presentation with respect to
the terms or conditions of this Agreement without the prior written consent of
the other party (such consent not to be unreasonably withheld or delayed). This
restriction shall not apply to disclosures required by law or regulation,
including as may be required in connection with any filings made with the
Securities and Exchange Commission or similar non-U.S. regulatory authority, or
by the disclosure policies of a major stock exchange; provided, however, that if
reasonably possible, the party making such disclosures shall inform the other
party prior to any such disclosures.

                         SECTION 12: DISPUTE RESOLUTION

        12.1 The parties intend that they shall resolve disputes and differences
regarding the performance of their respective obligations under this Agreement
in a spirit of cooperation and common purpose. In cases in which that does not
occur (other than as to a question relating to patent validity), any differences
between the parties arising from or in connection with this Agreement shall be
resolved in accordance with the procedures set forth in this Section 12.

        12.2 Any dispute arising from or in connection with this Agreement
during the Development Phase shall be first presented to a senior executive of
each party (with each party designating its own senior executive that shall
handle such dispute) for resolution. If the designated senior executives are
unable to resolve the dispute within thirty (30) days, then either party may
initiate arbitration pursuant to Section 12.3.

        12.3 Subject to Section 12.2, any and all disputes or legal proceedings
to enforce this Agreement (other than as to a question relating to patent
validity and except for any action to compel arbitration hereunder or an action
to enforce any award or judgment rendered thereby) or in any way related to this
Agreement shall be governed by this Section 12.3. Both the agreement of the
parties to arbitrate any and all claims and disputes under this Agreement as
provided in this Section 12.3, and the results, determination, finding, judgment
and/or award rendered through such arbitration, shall be final and binding on
the parties thereto and may be specifically enforced by legal proceedings in a
court having jurisdiction over the party in question. Arbitration proceedings
under this Agreement shall be conducted under the auspices of the International
Arbitration Rules of the American Arbitration Association (the "AAA") in New
York. Dynal shall appoint one (1) arbitrator, and Xcyte one (1) arbitrator,
within a term of thirty (30) days from the date arbitration is required or
invoked by the parties, and the two (2) arbitrators so appointed shall appoint
the third arbitrator within a term of thirty (30) days from the date on which
the later of the two (2) arbitrators have been selected, all in accordance with
the rules of the AAA. If either party fails to select its arbitrator within the
term mentioned above, or in the event that the two (2) selected arbitrators are
unable or unwilling to select a third arbitrator within thirty (30) days, one
shall be appointed in accordance with the rules of the AAA, and the three (3)
arbitrators so selected shall constitute the arbitration panel for purposes of
the dispute. Unless agreed otherwise by the parties, the parties shall have
thirty (30) days thereafter to submit



                                      -19-
<PAGE>   20

their position to the arbitrators, and the arbitrators shall be instructed and
required to render their decision within thirty (30) days following completion
of the arbitration. In any arbitration, the prevailing party shall be entitled
to reimbursement of its reasonable attorneys' fees and the parties shall use all
reasonable efforts to keep arbitration costs to a minimum.

        12.4 Notwithstanding anything in this Section 12 to the contrary, if
either party shall reasonably determine the need to seek injunctive or other
expedited relief in connection with this Agreement, such party may do so in a
court of competent jurisdiction.

                          SECTION 13: OTHER PROVISIONS

        13.1 This Agreement contains the entire agreement between the parties
relating to the subject matter hereof and all prior understandings,
representations and warranties between the parties (including the Letter
Agreement) are superseded by this Agreement.

        13.2 None of the terms of this Agreement shall be deemed to be waived or
amended by either party unless such a waiver or amendment specifically
references this Agreement and is in writing signed by the party to be bound.

        13.3 Notwithstanding anything contained herein, in no event shall either
party be liable for any delay or failure hereunder for reasons beyond the
control of such party, provided, however, that such party shall notify the other
promptly of anticipated delays and shall use all reasonable efforts to perform
as soon as possible.

        13.4 All notices and demands required or permitted to be given or made
pursuant to this Agreement shall be deemed effective upon receipt, in English
and in writing (which term shall include telecopy) addressed to the people named
below and shall be personally delivered or mailed by prepaid air mail, or sent
by international courier requiring signed receipt for delivery, or sent by
telecopy, provided such telecopy is promptly confirmed by electronic return
receipt, addressed as follows:

<TABLE>
        <S>                                 <C>
        If to Xcyte:                        If to Dynal:

        Xcyte Therapies, Inc.               Dynal A.S.
        1124 Columbia St., Suite 130        P.O. Box 158 Skoyen
        Seattle, WA 98104                   N-0212 Oslo, Norway
        Telecopy: 206-262-0900              Telecopy:  011-47-22-50-7015
        Attn: President, CEO                Attn:  President, CEO
</TABLE>

or to such other address or person which either party may notify the other in
writing.

        13.5 This Agreement shall be binding upon and inure to the benefit of
the parties and their permitted successors and assigns. This Agreement shall be
assignable by either party (i) with the written consent of the other party, such
consent not to be unreasonably withheld; or (ii) to an Affiliate; or (iii) to
any successor by merger or upon sale of all or substantially all of its



                                      -20-
<PAGE>   21

assets. Any attempted assignment which does not comply with the terms of this
Section 13.4 shall be void.

        13.6 This Agreement shall be governed by the laws of the State of New
York, and all rights and remedies shall be governed by such laws without regard
to principles of conflicts of law. The Convention on Contracts for the
International Sale of Goods shall not apply to this Agreement.

        13.7 The parties do not intend to violate any public policy or statutory
or common law. However, if any sentence, paragraph, clause or combination of
this Agreement is in violation of any law or is found to be otherwise
unenforceable by a court from which there is no appeal, or no appeal is taken,
such sentence, paragraph, clause, or combination of the same shall be deleted
and the remainder of this Agreement shall remain binding, provided that such
deletion does not alter the basic structure of this Agreement. The parties shall
negotiate in good faith to substitute for any such invalid or unenforceable
provision, a valid and enforceable provision that achieves to the greatest
extent possible the economic, legal and commercial objectives of the invalid or
unenforceable provision. In the event the basic structure of this Agreement is
altered as a result of such deletion, the parties shall renegotiate this
Agreement in good faith, but should such negotiations not result in a new
Agreement within ninety (90) days of the initiation of such negotiations, then
this Agreement may be terminated by either party by thirty (30) days notice to
the other.

        13.8 The titles to sections of this Agreement are intended for the
purpose of assisting the parties when working with this Agreement, and are not
intended to have any effect on the interpretation of this Agreement. Where
appropriate herein, singular terms shall be interpreted in the plural and plural
terms interpreted as singular.

        13.9 Dynal acknowledges that it is not an agent of Xcyte and has no
authority to speak for, represent, or obligate Xcyte in any way, without first
receiving written authorization from Xcyte. Xcyte acknowledges that it is not an
agent of Dynal and has no authority to speak for, represent, or obligate Dynal
in any way, without first receiving written authorization from Dynal. This
Agreement does not and shall not be deemed to create any relationship of a joint
venture or a partnership.

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

                                     * * *



                                      -21-
<PAGE>   22

        IN WITNESS WHEREOF, the parties have executed this Agreement by their
duly authorized representatives.

XCYTE THERAPIES, INC.                       DYNAL A.S.


By:     /s/ Ronald Jay Berenson             By:     /s/ Jeff Bork
   ---------------------------------           ---------------------------------
Name:          Ronald Jay Berenson          Name:          Jeff Bork
     -------------------------------             -------------------------------
Title:  President & CEO                     Title:  CEO/President
      ------------------------------              ------------------------------
7 December 1999                             7 December 1999



<PAGE>   23

                                 ATTACHMENT LIST



        Attachment A         The Antibodies

        Attachment B         Work Plans

        Attachment C         Dynabeads(R) M-450 Epoxy T Specifications

        Attachment D         Dynabeads(R) M-450 CD3/CD28 T Specifications

        Attachment E         Per Vial Prices

        Attachment F         Quality Assurance -- Products

        Attachment G         Quality Assurance -- Antibodies



<PAGE>   24

        EXECUTION COPY

        [*]


*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.


<PAGE>   25

                                  Attachment A
                                       to
       Development and Supply Agreement dated as of August 1, 1999 between
             Xcyte Therapies, Inc. and Dynal A.S. (the "Agreement")

               (Terms used herein and not otherwise defined below
                   have the meanings defined in the Agreement)


                                 The Antibodies

[*]


*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.



<PAGE>   26

                                  Attachment B

                                       to

       Development and Supply Agreement dated as of August 1, 1999 between
             Xcyte Therapies, Inc. and Dynal A.S. (the "Agreement")

               (Terms used herein and not otherwise defined below
                   have the meanings defined in the Agreement)

                                   Work Plans

                           Work Plans attached hereto.



<PAGE>   27

                             [Attachment B-1 to B-4]

                             [illustrations/graphs]

                                       [*]


*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.

<PAGE>   28

                                                                    ATTACHMENT C

                                       [*]




*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.
<PAGE>   29

                                  Attachment D

[*]



*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.
<PAGE>   30

                                  ATTACHMENT E
                                       TO
       DEVELOPMENT AND SUPPLY AGREEMENT DATED AS OF AUGUST 1, 1999 BETWEEN
             XCYTE THERAPIES, INC. AND DYNAL A.S. (THE "AGREEMENT")

               (Terms used herein and not otherwise defined below
                  have the meanings defined in the Agreement)

[*]



*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.
<PAGE>   31

                                  ATTACHMENT F

                                       TO

                        DEVELOPMENT AND SUPPLY AGREEMENT

                       DATED AS OF AUGUST 1, 1999 BETWEEN

             XCYTE THERAPIES, INC. AND DYNAL A.S. (THE "AGREEMENT")

               (Terms used herein and not otherwise defined below

                   have the meanings defined in the Agreement)

                          QUALITY ASSURANCE -- PRODUCTS

[*]




*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.
<PAGE>   32

                                  ATTACHMENT G
                                       TO
       DEVELOPMENT AND SUPPLY AGREEMENT DATED AS OF AUGUST 1, 1999 BETWEEN
             XCYTE THERAPIES, INC. AND DYNAL A.S. (THE "AGREEMENT")

               (Terms used herein and not otherwise defined below
                   have the meanings defined in the Agreement)

[*]



*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.