<PAGE>


                                                                   Exhibit 10.21









                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                          DATED AS OF NOVEMBER 7, 2001


                                      AMONG


                          HUMAN GENOME SCIENCES, INC.,
                                   AS LESSEE,


                          GENOME STATUTORY TRUST 2001A,
                                   AS LESSOR,


                              FLEET NATIONAL BANK,
                    AS FLEET NATIONAL BANK COLLATERAL AGENT,


                                       AND


                    THE PERSONS LISTED ON SCHEDULE I HERETO,
                                AS BENEFICIARIES








[An identical liquid collateral agreement was also entered into between First
Union National Bank as First Union Collateral Agent, Human Genome Sciences, Inc.
as lessee, the Genome Statutory Trust 2001A as lessor, and the persons listed on
Schedule I of that agreement.]

<PAGE>


                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                THIS FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT, dated as
of November 7, 2001 (this "Agreement"), by and among HUMAN GENOME SCIENCES, INC.
("Lessee"), GENOME STATUTORY TRUST 2001A, a Connecticut statutory trust
("Lessor"), FLEET NATIONAL BANK ("Fleet National Bank Collateral Agent"), as
Fleet National Bank Collateral Agent for the benefit of the Beneficiaries, and
the Persons listed on Schedule I hereto (the "Beneficiaries").

                              W I T N E S S E T H:


                WHEREAS, pursuant to the Participation Agreement, Ground Lessor
and Ground Lessee have entered into the Ground Lease pursuant to which Ground
Lessee has leased the Traville Site from Ground Lessor;

                WHEREAS, pursuant to the Lease, Lessor has leased the Properties
to Lessee;

                WHEREAS, in connection with the Participation Agreement, Lessee
has opened the Account (Fleet National Bank) with the Fleet National Bank
Custodian, in the name of Lessee, subject to a first priority lien and security
interest in favor of Lessor, to hold Securities (which initially are the
Securities described in Exhibit A hereto);

                WHEREAS, in connection herewith, Lessee, Lessor, the Fleet
National Bank Collateral Agent, the Beneficiaries and the Fleet National Bank
Custodian are entering into the Fleet National Bank Custody Agreement dated as
of the Documentation Date;

                WHEREAS, as a material inducement for Lessor to enter into the
Participation Agreement and the other Operative Documents to which it is a
party, Lessee has agreed to execute and deliver this Agreement for the purpose
of securing the Secured Lessee Obligations and for the purpose of subjecting the
Fleet National Bank Liquid Collateral to the Lien of this Agreement as security
for the payment and performance of the Secured Lessee Obligations; and

                WHEREAS, as a material inducement for the Beneficiaries to enter
into the Participation Agreement and the other Operative Documents to which they
are party, Lessor has agreed to execute and deliver this Agreement for the
purpose of securing the Secured Lessor Obligations and for the purpose of
subjecting to the extent of the Lessor's interest therein the Fleet National
Bank Liquid Collateral to the Lien of this Agreement as security for the payment
and performance of the Secured Lessor Obligations.

                IT IS HEREBY COVENANTED AND DECLARED by and between the parties
hereto and their respective successors and assigns that the terms upon which the
Fleet National Bank Liquid Collateral shall be held and used are as follows:

<PAGE>
                                FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                    ARTICLE 1

                           DEFINITIONS, INTERPRETATION


                1.1     CERTAIN DEFINITIONS


                (a)     Subject to the following sentence, Appendix A to the
Participation Agreement applies (including as to rules of usage) to this
Agreement. Except as contained in Section 1.1(b), capitalized terms used herein
shall have the respective meanings assigned thereto in Appendix A to the
Participation Agreement for all purposes hereof.

                (b)     In this Agreement the following capitalized terms have
the following respective meanings:

                "ACCOUNT (FLEET NATIONAL BANK)" means Securities Account number
        _____ of Lessee maintained with the Fleet National Bank Custodian (or
        any successor custodian) subject to the Liens and security interests
        granted hereunder, together with all subaccounts thereto and any new
        accounts and subaccounts established and maintained in replacement
        thereof with the Fleet National Bank Custodian or any successor
        custodian.

                "ADDITIONAL COLLATERAL DELIVERY DATE" means, with respect to
        each Additional Collateral Demand, the day on or before the fifth
        Business Day following the making of an Additional Collateral Demand or
        if one or more Additional Collateral Demands are outstanding and the
        aggregate amount of the Pledged Security required to be transferred to
        the Account (Fleet National Bank) exceeds $5,000,000, then with respect
        to all outstanding transfers of Pledged Securities, on the Business Day
        next following the Business Day when the aggregate amounts required to
        be transferred to such Account (Fleet National Bank) first exceeds
        $5,000,000.


                "ADDITIONAL COLLATERAL DEMAND" has the meaning set forth in
        Section 2.5(a)(i).

                "ADDITIONAL COLLATERAL DEMAND DATE" has the meaning set forth in
        Section 2.5(a)(iii).

                "ADDITIONAL LIQUID COLLATERAL" has the meaning set forth in
        Section 2.5(a)(i).

                "BENEFICIARIES" has the meaning set forth in the first paragraph
        of this Agreement and shall include the successors and permitted assigns
        of the Beneficiaries.

                "ENFORCEMENT EVENT" means a Lease Event of Default or a
        Construction Agency Event of Default.

                "ENFORCEMENT NOTICE" means a notice from the Fleet National Bank
        Collateral Agent to the Fleet National Bank Custodian in substantially
        the form of Exhibit A hereto.

                "ENTITLEMENT ORDER" has the meaning set forth in Section
        8-102(a)(8) of the Uniform Commercial Code and shall include, without
        limitation, any Enforcement Notice from the Fleet National Bank
        Collateral Agent.


                                       2
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                "FINANCIAL ASSET" has the meaning set forth in Section
        8-102(a)(9) of the Uniform Commercial Code.

                "FLEET NATIONAL BANK COLLATERAL AGENT" means Fleet National Bank
        Collateral Agent and shall include the successors and permitted assigns
        of Fleet National Bank Collateral Agent.

                "FLEET NATIONAL BANK CUSTODIAN" means the Fleet National Bank
        Collateral Agent or any successor custodian appointed pursuant to the
        Fleet National Bank Custody Agreement.

                "FLEET NATIONAL BANK CUSTODY AGREEMENT" means the Fleet National
        Bank Custody Agreement, dated as of November 7, 2001, among Lessee,
        Lessor, the Fleet National Bank Collateral Agent, the Beneficiaries and
        the Fleet National Bank Custodian.

                "FLEET NATIONAL BANK LIQUID COLLATERAL" has the meaning set
        forth in Section 2.1(a)(i).

                "INVESTMENT PROPERTY" has the meaning set forth in Section
        9-102(a)(49) of the Uniform Commercial Code.

                "PARTICIPATION AGREEMENT" means the Participation Agreement,
        dated as of November 7, 2001, among Lessee, as Lessee and Construction
        Agent, Traville LLC, as Ground Lessor, Lessor, as Ground Lessee and
        Lessor, BancBoston Leasing Investments Inc. and First Union National
        Bank, as Investors, EagleFunding Capital Corporation, as Lender, Fleet
        Securities, Inc., as Administrator, Fleet National Bank and First Union
        National Bank, as Liquidity Providers, Fleet National Bank, as Fleet
        National Bank Collateral Agent, First Union National Bank, as First
        Union Collateral Agent and Fleet National Bank, as Administrative Agent
        and Liquidity Agent.

                "PLEDGED SECURITIES" means the Securities credited to the
        Account (Fleet National Bank) from time to time, less any Pledged
        Securities released to Lessee in accordance with the Fleet National Bank
        Liquid Collateral Agreement and the Participation Agreement.

                "PROCEEDS" of the Fleet National Bank Liquid Collateral has the
        meaning given in Section 9-102 of the Uniform Commercial Code and shall
        include cash, securities and other property realized in respect of, and
        distributions in kind of, the Fleet National Bank Liquid Collateral, as
        applicable.

                "SECURED LESSEE OBLIGATIONS" means all obligations of Lessee now
        or hereafter existing under the Participation Agreement, the Lease and
        each other Operative Document, whether for principal, interest, costs,
        fees, expenses or otherwise, and all other obligations of Lessee to
        Lessor and the Beneficiaries, howsoever created, arising or evidenced,
        whether direct or indirect, absolute or contingent or now or hereafter
        existing or due or to become due under the Operative Documents.

                                       3
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                "SECURED LESSOR OBLIGATIONS" means all obligations of Lessor now
        or hereafter existing under the Participation Agreement and each other
        Operative Document, whether for principal, interest, costs, fees,
        expenses or otherwise, and all other obligations of Lessor to the
        Beneficiaries, howsoever created, arising or evidenced, whether direct
        or indirect, absolute or contingent or now or hereafter existing or due
        or to become due.

                "SECURITIES" has the meaning given that term in Section
        8-102(a)(15) of the Uniform Commercial Code.

                "SECURITIES ACCOUNT" has the meaning set forth in Section
        8-501(a) of the Uniform Commercial Code.

                "SECURITIES INTERMEDIARY" has the meaning set forth in Section
        8-102(a)(14) of the Uniform Commercial Code.

                "SECURITY ENTITLEMENT" has the meaning set forth in Section
        357.2 of the Treasury Regulations and Section 8-102(a)(17) of the
        Uniform Commercial Code.

                "SETTLEMENT DATE" has the meaning set forth in Section
        2.5(a)(iv).

                "TREASURY REGULATIONS" means 31 CFR Part 357, as amended by
        regulations published at 61 Fed. Reg. 43626 (August 23, 1996) and as may
        be amended from time to time by any subsequent regulations.

                "UNIFORM COMMERCIAL CODE" and "UCC" means the Uniform Commercial
        Code, as amended, as in effect in the State of New York from time to
        time.

                                    ARTICLE 2

                              GRANTING OF SECURITY


                2.1     GRANTING OF SECURITY INTERESTS

                (a)     Granting of Security Interest from Lessee to Lessor

                (i)     Lessee has established and shall maintain at all times,
        so long as there are Secured Lessee Obligations outstanding, the Account
        (Fleet National Bank) with the Fleet National Bank Custodian, which
        Account (Fleet National Bank) shall be a Securities Account, shall be in
        the name of Lessee but subject to the first priority security interest
        of the Fleet National Bank Collateral Agent for the benefit of the
        Beneficiaries and itself, and shall have the designation as provided in
        the Fleet National Bank Custody Agreement. As security for the due,
        prompt and complete payment and performance of the Secured Lessee
        Obligations, Lessee hereby unconditionally, irrevocably and presently
        conveys, mortgages, assigns, transfers, and pledges to Lessor, and
        hereby grants to Lessor, a first Lien on, and a first priority security
        interest in, all right, title and interest in, to and under the Pledged
        Securities; the Account (Fleet National Bank) and all funds, cash and
        cash equivalents, Financial Assets, Investment Property and any other
        property from time to time credited or required to be credited thereto
        including any Additional


                                       4
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


        Liquid Collateral transferred to the Account (Fleet National Bank)
        pursuant to Section 2.5(a) (and all certificates, cash balances and
        instruments from time to time representing or evidencing the same); all
        notes, certificates of deposit, deposit amounts, checks and other
        investments from time to time hereafter delivered to or otherwise
        possessed by the Fleet National Bank Custodian in substitution for any
        or all of the foregoing; all rights, claims, and causes of action, if
        any, that Lessee may have against the Fleet National Bank Custodian or
        any other person in respect of the foregoing; all interest, dividends,
        cash, instruments and other property from time to time received,
        receivable, or distributed in respect of any or all of the foregoing;
        all Security Entitlements of Lessee in or with respect to any and all of
        the foregoing including all Security Entitlements credited to or held in
        the Account (Fleet National Bank); and all Proceeds of any and all of
        the foregoing, whether now existing or hereafter acquired (collectively,
        the "Fleet National Bank Liquid Collateral").

                (ii)    To perfect the security interest granted by Lessee to
        Lessor in the Fleet National Bank Liquid Collateral hereunder, Lessee
        hereby gives control over the Fleet National Bank Liquid Collateral to
        Lessor and shall file financing statements in respect of the Fleet
        National Bank Liquid Collateral in the manner and at the place or places
        set forth in the Uniform Commercial Code and make such other filing or
        take such other measures as may be prescribed by Applicable Law or
        reasonably requested by Lessor, the Fleet National Bank Collateral Agent
        or the Beneficiaries.

                (iii)   Lessee will cause to be done, executed, acknowledged and
        delivered all such further acts, conveyances and assurances as Lessor,
        the Fleet National Bank Collateral Agent or the Beneficiaries shall
        reasonably require for accomplishing the purposes of this Agreement, and
        which are necessary or desirable to continue the perfection and priority
        of the Liens and security interests granted under this Agreement.

                (iv)    Lessee agrees for the benefit of Lessor and the
        Beneficiaries, at no expense to Lessor, the Fleet National Bank
        Collateral Agent or the Beneficiaries, to defend Lessor's and the Fleet
        National Bank Collateral Agent's security interest in and to the Fleet
        National Bank Liquid Collateral against the claims of any Person and to
        ensure that Lessor and the Fleet National Bank Collateral Agent shall
        have at all times pursuant to this Agreement a first priority perfected
        Lien on and security interest in the Fleet National Bank Liquid
        Collateral, subject to no prior or equal Lien whatsoever.

                (v)     All rights of Lessor hereunder, and all obligations of
        Lessee hereunder, shall be absolute and unconditional irrespective of:

                        (1)     any lack of validity or enforceability of this
        Agreement or any Operative Document;

                        (2)     any change in the time, manner or place of
        payment of, or any other term of, all or any of the Secured Lessee
        Obligations, or any amendment or waiver of or any consent to any
        departure from this Agreement or the Operative Documents;



                                       5
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                        (3)     any taking, exchange, release or non-perfection
        of any other Fleet National Bank Liquid Collateral or taking, release or
        amendment or waiver of or consent to departure from any guaranty or
        indemnity for all or any of the Secured Lessee Obligations; and

                        (4)     any manner of application of Fleet National Bank
        Liquid Collateral, or Proceeds thereof, to all or any of the Secured
        Lessee Obligations, or any manner of sale or disposition of any Fleet
        National Bank Liquid Collateral for all or any of the Secured Lessee
        Obligations or any other assets of Lessee.

                (vi)    Lessee agrees, for the benefit of Lessor, the Fleet
        National Bank Collateral Agent and the Beneficiaries, that it shall not
        be entitled to withdraw, liquidate, sell, convey, endorse, negotiate, or
        in any way dispose of, or create, incur, or permit to exist any pledge,
        mortgage, Lien, charge, encumbrance or security interest whatsoever, or
        cause any of the foregoing to occur in or with respect to, any of the
        Fleet National Bank Liquid Collateral, any interest therein or any cash
        or other property held and maintained in or credited to the Account
        (Fleet National Bank).

                (vii)   Except as expressly set forth herein or in the other
        Operative Documents, Lessee hereby expressly waives diligence,
        presentment, demand for payment, protest, any requirement that any right
        or power be exhausted or any action be taken against any Person, all
        notices (whether non-payment by Lessee or any other Person, dishonor,
        protest or otherwise) with respect to any of the Secured Lessee
        Obligations and notice of acceptance of this Agreement.

                (viii)  Subject to Sections 2.1(b)(ii) and 2.1(b)(viii), all
        cash and cash equivalents deposited in or credited to the Account (Fleet
        National Bank) from time to time shall be under the sole dominion and
        control of Lessor and held by the Fleet National Bank Custodian pursuant
        to the Fleet National Bank Custody Agreement as Lessor's agent and
        bailee, and Lessor shall have the sole right to make or direct
        withdrawals of cash or cash equivalents from the Account (Fleet National
        Bank).

                (b)     Granting of Security Interest from Lessor to the Fleet
National Bank Collateral Agent

                (i) As security for the due, prompt and complete payment and
        performance of the Secured Lessor Obligations, Lessor hereby
        unconditionally, irrevocably and presently conveys, mortgages, assigns,
        transfers, and pledges to the Fleet National Bank Collateral Agent, for
        the benefit of the Beneficiaries, and hereby grants to the Fleet
        National Bank Collateral Agent, for the benefit of the Beneficiaries, a
        first Lien on, and a first priority security interest in, all of
        Lessor's right, title and interest in, to and under the Fleet National
        Bank Liquid Collateral, the Pledged Securities; the Account (Fleet
        National Bank) and all funds, cash and cash equivalents, Financial
        Assets, Investment Property and any other property from time to time
        credited or required to be credited thereto including any Additional
        Liquid Collateral transferred to the Account (Fleet National Bank)
        pursuant to Section 2.5(a) (and all certificates, cash balances and
        instruments from time to time representing or evidencing the same); all
        notes, certificates of deposit,


                                       6
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


        deposit amounts, checks and other investments from time to time
        hereafter delivered to or otherwise possessed by the Fleet National Bank
        Custodian in substitution for any or all of the foregoing; all rights,
        claims, and causes of action, if any, that Lessee or Lessor may have
        against the Fleet National Bank Custodian or any other person in respect
        of the foregoing; all interest, dividends, cash, instruments and other
        property from time to time received, receivable, or distributed in
        respect of any or all of the foregoing; all Security Entitlements of
        Lessee or Lessor in or with respect to any and all of the foregoing
        including all Security Entitlements credited to or held in the Account
        (Fleet National Bank); and all Proceeds of any and all of the foregoing,
        whether now existing or hereafter acquired.

                (ii)    To perfect the security interest granted by Lessor to
        the Fleet National Bank Collateral Agent in the Fleet National Bank
        Liquid Collateral hereunder, Lessor hereby gives control over the Fleet
        National Bank Liquid Collateral to the Fleet National Bank Collateral
        Agent and shall file financing statements in respect of the Fleet
        National Bank Liquid Collateral in the manner and at the place or places
        set forth in the Uniform Commercial Code and make such other filing or
        take such other measures as may be prescribed by Applicable Law or
        reasonably requested by the Fleet National Bank Collateral Agent or the
        Beneficiaries.

                (iii)   Lessor will cause to be done, executed, acknowledged and
        delivered all such further acts, conveyances and assurances as the Fleet
        National Bank Collateral Agent or the Beneficiaries shall reasonably
        require for accomplishing the purposes of this Agreement, and which are
        necessary or desirable to continue the perfection and priority of the
        Liens and security interests granted under this Agreement.

                (iv)    Intentionally Omitted.

                (v)     All rights of the Fleet National Bank Collateral Agent
        and the Beneficiaries hereunder, and all obligations of Lessor
        hereunder, shall be absolute and unconditional irrespective of:

                        (1)     any lack of validity or enforceability of this
        Agreement or any Operative Document;

                        (2)     any change in the time, manner or place of
        payment of, or any other term of, all or any of the Secured Lessor
        Obligations, or any amendment or waiver of or any consent to any
        departure from this Agreement or the Operative Documents;

                        (3)     any taking, exchange, release or non-perfection
        of any other Fleet National Bank Liquid Collateral or taking, release or
        amendment or waiver of or consent to departure from any guaranty or
        indemnity for all or any of the Secured Lessor Obligations; and

                        (4)     any manner of application of Fleet National Bank
        Liquid Collateral, or Proceeds thereof, to all or any of the Secured
        Lessor Obligations, or any manner of sale or disposition of any Fleet
        National Bank Liquid Collateral for all or any of the Secured Lessor
        Obligations or any other assets of Lessor.

                                       7
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                (vi)    Lessor agrees, for the benefit of the Beneficiaries,
        that it shall not be entitled to withdraw, liquidate, sell, convey,
        endorse, negotiate, or in any way dispose of, or create, incur, or
        permit to exist any pledge, mortgage, Lien, charge, encumbrance or
        security interest whatsoever, or cause any of the foregoing to occur in
        or with respect to, any of the Fleet National Bank Liquid Collateral,
        any interest therein or any cash or other property held and maintained
        in or credited to the Account (Fleet National Bank).

                (vii)   Except as expressly set forth herein or in the other
        Operative Documents, Lessor hereby expressly waives diligence,
        presentment, demand for payment, protest, any requirement that any right
        or power be exhausted or any action be taken against any Person, all
        notices (whether non-payment by Lessor or any other Person, dishonor,
        protest or otherwise) with respect to any of the Secured Lessor
        Obligations and notice of acceptance of this Agreement.

                (viii)  Anything to the contrary herein notwithstanding, all
        cash and cash equivalents deposited in or credited to the Account (Fleet
        National Bank) from time to time shall be under the sole dominion and
        control of the Fleet National Bank Collateral Agent and held by the
        Fleet National Bank Custodian pursuant to the Fleet National Bank
        Custody Agreement as the Fleet National Bank Collateral Agent's agent
        and bailee, and the Fleet National Bank Collateral Agent shall have the
        sole right to make or direct withdrawals of cash or cash equivalents
        from the Account (Fleet National Bank).

                2.2     REMEDIES

                The Fleet National Bank Collateral Agent may, upon the
occurrence and continuance of an Enforcement Event and the delivery of an
Enforcement Notice to the Fleet National Bank Custodian by the Fleet National
Bank Collateral Agent, and without the consent of Lessee or any other Person,
exercise certain remedies with respect to the Fleet National Bank Liquid
Collateral as provided herein, including, but not limited to, directing the
Fleet National Bank Custodian to sell or cause to be sold an amount of the Fleet
National Bank Liquid Collateral and otherwise acting in all respects as the
owner of the Fleet National Bank Liquid Collateral.

                2.3     PLEDGORS REMAIN LIABLE

                Anything to the contrary herein notwithstanding, (i) Lessee
shall remain liable under Operative Documents to Lessor and Lessor shall remain
liable under the Operative Documents to the Beneficiaries, each to the extent
set forth therein to perform all of their duties and obligations, if any,
thereunder to the same extent as if this Agreement had not been executed and the
pledges hereunder had not been made, (ii) the exercise by Lessor or the Fleet
National Bank Collateral Agent of any of their rights hereunder shall not
release Lessee or Lessor from any of their duties or obligations, if any, under
the Operative Documents, except to the extent that such obligations are
satisfied by the payment of an amount hereunder or pursuant to the Fleet
National Bank Custody Agreement. The execution and delivery of this Agreement
shall not in any way diminish the respective rights and obligations of Lessee,
Lessor or the Fleet National Bank Collateral Agent (or any other party thereto)
under the Operative Documents.

                                       8
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                2.4     INSTRUCTIONS REGARDING THE ACCOUNT (FLEET NATIONAL BANK)

                It is hereby acknowledged and agreed that pursuant to the Fleet
National Bank Custody Agreement, other than as expressly set forth therein and
herein, only the Fleet National Bank Collateral Agent is entitled to give
instructions and Entitlement Orders to the Fleet National Bank Custodian with
respect to the Account (Fleet National Bank) , any and all Securities credited
to the Account (Fleet National Bank) and any other Fleet National Bank Liquid
Collateral.

                2.5     ADDITIONAL FLEET NATIONAL BANK LIQUID COLLATERAL

                (a)    (i)      Pursuant to the Participation Agreement, the
Fleet National Bank Collateral Agent shall have the right at any time, and from
time to time upon delivery to Lessee of a demand given by telephone or fax (and
confirmed in writing) (a "Additional Collateral Demand"), to require Lessee to
transfer additional Permitted Investments (the "Additional Liquid Collateral")
to the Account (Fleet National Bank) by the Additional Collateral Delivery Date
to ensure that the Adjusted Market Value, in the case of Properly Margined
Liquid Collateral, and the Fair Market Value, in the case of Non-Properly
Margined Liquid Collateral of Fleet National Bank Liquid Collateral in which
Lessor and the Fleet National Bank Collateral Agent have a first priority
perfected security interest shall be greater than or equal to the applicable
Required Liquid Collateral Amount for the Fleet National Bank Liquid Collateral;
provided, that after taking into account a transfer of Pledged Securities the
Account (Fleet National Bank) shall satisfy and at all times thereafter satisfy
the Concentration Limits.

                (ii)    Without limiting Section 2.5(a)(i) above Lessee shall
        transfer such Additional Liquid Collateral to the Account (Fleet
        National Bank) by the Additional Collateral Delivery Date to ensure
        that, the Adjusted Market Value, in the case of Properly Margined Liquid
        Collateral, and the Fair Market Value, in the case of Non-Properly
        Margined Liquid Collateral of Fleet National Bank Liquid Collateral in
        which Lessor and the Fleet National Bank Collateral Agent have a first
        priority perfected security interest shall be greater than or equal to
        the applicable Required Liquid Collateral Amount for the Fleet National
        Bank Liquid Collateral.

                (b)     Pursuant to the account agreements entered into with the
Fleet National Bank, Fleet National Bank Custodian shall have the right to
direct the reinvestment of any Pledged Securities credited to the Account (Fleet
National Bank) upon the maturity of such Pledged Securities or prior thereto.

                (c)     The parties hereto acknowledge and agree that (i) any
Permitted Investments transferred to the Account (Fleet National Bank) pursuant
to Sections 2.5(a) or 2.5(b) or otherwise shall be deemed Pledged Securities for
the purposes of this Agreement, (ii) on any transfer date, the Fleet National
Bank Collateral Agent shall instruct Lessee and the Fleet National Bank
Custodian to take or cause to be taken, and Lessee and the Fleet National Bank
Custodian shall take or cause to be taken, at Lessee's sole cost and expense,
such action as is necessary create in Lessor a valid perfected first priority
security interest on such date in such Pledged Securities, and (iii) on any
transfer date, the Fleet National Bank Collateral Agent shall instruct Lessee,
Lessor and the Fleet National Bank Custodian to take or cause to be taken, and


                                       9
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


Lessee, Lessor and the Fleet National Bank Custodian shall take or cause to be
taken, at Lessee's sole cost and expense, such action as is necessary create in
the Fleet National Bank Collateral Agent a valid perfected first priority
security interest on such date in Lessor's right, title and interest in, to and
under such Pledged Securities. Without limiting the foregoing, the Fleet
National Bank Collateral Agent is hereby authorized to complete Exhibit A hereto
upon acquisition of such Pledged Securities.

                                   ARTICLE 3

                               COVENANTS OF LESSEE

                3.1     NO SET-OFF

                (a)     Lessee, Lessor, the Fleet National Bank Collateral Agent
and the Beneficiaries acknowledge that the Fleet National Bank Custodian may
from time to time have other relationships with Lessee, Lessor, the Fleet
National Bank Collateral Agent or the Beneficiaries that are not related to the
transactions contemplated by this Agreement or the Participation Agreement and
not secured hereunder.

                (b)     No set-off, counterclaim, reduction or diminution of any
obligation, or any defense of any kind or nature (other than complete
performance by Lessee of its obligations hereunder) which Lessee may have to
assert against Lessor, the Fleet National Bank Collateral Agent or any
Beneficiary shall be available hereunder to, or shall be asserted by, Lessee in
any action arising out of the transactions contemplated hereby.

                (c)     Lessee covenants that it shall not terminate the Fleet
National Bank Custody Agreement without the Beneficiaries' express prior written
consent, other than in accordance with the terms thereof.

                3.2     FURTHER TRANSFERS

                As long as the security interest in and the Lien on the Fleet
National Bank Liquid Collateral created hereunder in favor of Lessor and the
Fleet National Bank Collateral Agent shall not have been discharged or released,
Lessee shall not sell, transfer, convey, assign, grant a Lien on or security
interest in, or otherwise dispose of the Fleet National Bank Liquid Collateral,
or any part thereof, without the prior written consent of the Fleet National
Bank Collateral Agent except as provided herein or in the Fleet National Bank
Custody Agreement.

                                   ARTICLE 4

                         COVENANTS OF LESSOR AND LESSEE

                4.1     NO SET-OFF

                (a)     No set-off, counterclaim, reduction or diminution of any
obligation, or any defense of any kind or nature (other than complete
performance by Lessor of its obligations hereunder) which Lessor may have to
assert against the Fleet National Bank Collateral Agent or


                                       10
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


any Beneficiary shall be available hereunder to, or shall be asserted by, Lessor
in any action arising out of the transactions contemplated hereby.

                (b)     Lessor covenants that it shall not terminate the Fleet
National Bank Custody Agreement without the Beneficiaries' express prior written
consent, other than in accordance with the terms thereof.

                4.2     FURTHER TRANSFERS

                As long as the security interest in and the Lien on the Fleet
National Bank Liquid Collateral created hereunder in favor of the Fleet National
Bank Collateral Agent shall not have been discharged or released, Lessor shall
not sell, transfer, convey, assign, grant a Lien on or security interest in, or
otherwise dispose of the Fleet National Bank Liquid Collateral, or any part
thereof, without the prior written consent of the Fleet National Bank Collateral
Agent except as provided herein or in the Fleet National Bank Custody Agreement.

                                   ARTICLE 5

                                    REMEDIES

                5.1     REMEDIES UPON ENFORCEMENT EVENT

                (a)     Lessee and Lessor agree that if any Enforcement Event
shall have occurred and be continuing the Fleet National Bank Collateral Agent
may exercise in respect of the Fleet National Bank Liquid Collateral, in
addition to other rights and remedies provided for herein or otherwise available
to it, all the rights and remedies of a secured party under the UCC (whether or
not the UCC applies to the Fleet National Bank Liquid Collateral at issue), and
the Fleet National Bank Collateral Agent may also, without notice except as
specified below, sell the Fleet National Bank Liquid Collateral or any part
thereof in one or more parcels at public or private sale, or at any of the Fleet
National Bank Collateral Agent's offices or elsewhere, for cash, on credit or
for future delivery, and upon such other terms as Collateral Agent may deem
commercially reasonable. Lessee and Lessor agrees that, to the extent notice of
sale shall be required by law, at least five Business Days' notice to Lessee and
Lessor of the time and place of any public sale or the time after which a
private sale is to be made shall constitute reasonable notification. The Fleet
National Bank Collateral Agent shall not be obligated to make any sale of Fleet
National Bank Liquid Collateral regardless of notice of sale having been given.
The Fleet National Bank Collateral Agent may adjourn any public or private sale
from time to time by announcement at the time and place fixed therefore and such
sale may, without further notice, be made at the time and place to which it was
so adjourned. The Fleet National Bank Collateral Agent shall be entitled to
consult with legal counsel and financial advisors in connection with the sale of
the Fleet National Bank Liquid Collateral and shall be protected in any
reasonable action or forbearance taken in connection with the advice of such
counsel or advisors.

                (b)     Each and every right, power and remedy given to the
Fleet National Bank Collateral Agent specifically or otherwise in this Agreement
shall be cumulative and shall be in addition to every other right, power and
remedy herein specifically given or now or hereafter existing at law, or under
the UCC, or otherwise in equity or by statute, and each and every right,


                                       11
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


power and remedy whether specifically herein given or otherwise existing may be
exercised from time to time and as often and in such order as may be deemed
expedient by the Fleet National Bank Collateral Agent, and the exercise or the
beginning of the exercise of any power or remedy shall not be construed to be a
waiver of the right to exercise at the same time or thereafter any other right,
power or remedy. No delay or omission by the Fleet National Bank Collateral
Agent in the exercise of any right, remedy or power or in the pursuance of any
remedy shall impair any such right, power or remedy or be construed to be a
waiver of any default on the part of the Fleet National Bank Collateral Agent or
to be an acquiescence therein.

                (c)     In case the Fleet National Bank Collateral Agent shall
have instituted any proceeding to enforce any right, power or remedy under this
Agreement by foreclosure, entry or otherwise, and such proceedings shall have
been discontinued or abandoned for any reason or shall have been determined
adversely to the Fleet National Bank Collateral Agent, then and in every such
case the Fleet National Bank Collateral Agent, Lessee and Lessor shall, subject
to any determination in such proceedings, be restored to their former positions
and rights hereunder with respect to the Fleet National Bank Liquid Collateral,
and all rights, remedies and powers of the Fleet National Bank Collateral Agent
shall continue as if no such proceedings had been instituted.

                (d)     Lessee and Lessor agree, to the full extent that it may
lawfully so agree, that neither it nor any Person claiming through or under it
will set up, claim or seek to take advantage of any appraisement, valuation,
stay, extension or redemption law now or hereafter in force, in order to
prevent, hinder or delay the enforcement or foreclosure of this Agreement, or
the absolute sale of the Fleet National Bank Liquid Collateral or any part
thereof, or the final and absolute putting into possession thereof, immediately
after such sale, of the purchaser thereof, and each of Lessee and Lessor, for
itself and all who may at any time claim through or under it, hereby waives to
the full extent that it may be lawful so to do, the benefit of all such laws,
and any and all right to have any of the properties or assets comprising the
Fleet National Bank Liquid Collateral marshalled upon any such sale, and agrees
that, subject to the terms of the Fleet National Bank Custody Agreement, the
Fleet National Bank Collateral Agent or any court having jurisdiction to
foreclose the Lien hereof may sell the Fleet National Bank Liquid Collateral as
an entirety or in such portions as the Fleet National Bank Collateral Agent may
determine.

                (e)     The Fleet National Bank Collateral Agent will promptly
upon receipt of any proceeds from any sale of any Fleet National Bank Liquid
Collateral pursuant to this Section 5.1 deliver such proceeds to the
Administrative Agent for distribution in accordance with Article X of the
Participation Agreement.

                5.2     POWERS OF ATTORNEY

                (a)     Lessee hereby irrevocably appoints the Fleet National
Bank Collateral Agent the true and lawful attorney of Lessee (with full power of
substitution) in the name, place and stead of, and at the expense of, Lessee (i)
for any period for the purpose of signing documents and taking other action to
perfect Lessor's and the Fleet National Bank Collateral Agent's security
interest in the Fleet National Bank Liquid Collateral and (ii) solely in
connection with the enforcement of the rights and remedies provided herein and
in the Fleet


                                       12
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


National Bank Custody Agreement upon the occurrence and during the continuation
of an Enforcement Event:

                (i)     to give any necessary receipts or acquittances for
        amounts collected or received thereunder;

                (ii)    to make all necessary transfers of any of the Fleet
        National Bank Liquid Collateral in connection with any sale or other
        disposition made pursuant hereto;

                (iii)   to execute and deliver for value all necessary or
        appropriate bills of sale, assignments and other instruments and
        agreements in connection with any such sale or other disposition, Lessee
        hereby ratifying and confirming all that such attorney (or any
        substitute) shall lawfully do hereunder and pursuant hereto; and

                (iv)    to sign any agreements, orders or other documents in
        connection with or pursuant to this Agreement (to the extent the same
        relate to the Fleet National Bank Liquid Collateral).


Nevertheless, if so requested by the Fleet National Bank Collateral Agent or a
purchaser, Lessee shall ratify and confirm to the extent it has the power to do
so, any such sale or other disposition by executing and delivering to the Fleet
National Bank Collateral Agent or such purchaser all proper bills of sale,
assignments, releases and other instruments as may be designated in any such
request.

                (b) Lessor hereby irrevocably appoints the Fleet National Bank
Collateral Agent the true and lawful attorney of Lessor (with full power of
substitution) in the name, place and stead of, and at the expense of, Lessor (i)
for any period for the purpose of signing documents and taking other action to
perfect the Fleet National Bank Collateral Agent's security interest in the
Fleet National Bank Liquid Collateral and (ii) solely in connection with the
enforcement of the rights and remedies provided herein and in the Fleet National
Bank Custody Agreement upon the occurrence and during the continuation of an
Enforcement Event:

                (i)     to give any necessary receipts or acquittances for
        amounts collected or received thereunder;

                (ii)    to make all necessary transfers of any of the Fleet
        National Bank Liquid Collateral in connection with any sale or other
        disposition made pursuant hereto;

                (iii)   to execute and deliver for value all necessary or
        appropriate bills of sale, assignments and other instruments and
        agreements in connection with any such sale or other disposition, Lessor
        hereby ratifying and confirming all that such attorney (or any
        substitute) shall lawfully do hereunder and pursuant hereto; and

                (iv)    to sign any agreements, orders or other documents in
        connection with or pursuant to this Agreement (to the extent the same
        relate to the Fleet National Bank Liquid Collateral).

                                       13
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


Nevertheless, if so requested by the Fleet National Bank Collateral Agent or a
purchaser, Lessor shall ratify and confirm to the extent it has the power to do
so, any such sale or other disposition by executing and delivering to the Fleet
National Bank Collateral Agent or such purchaser all proper bills of sale,
assignments, releases and other instruments as may be designated in any such
request.

                                   ARTICLE 6

                          RELEASE OF SECURITY INTEREST


                6.1     This Agreement shall remain in full force and effect
until payment in full by the Lessee of the Lease Balance, Supplemental Rent,
including Break Costs and all other amounts due and owing by it under the
Operative Documents and the termination of the Commitments of the Participants,
provided, however, that this Agreement and the security interests created hereby
shall earlier terminate and this Agreement shall be of no further force or
effect upon any sale or other final disposition by the Fleet National Bank
Collateral Agent of all of the property constituting the Fleet National Bank
Liquid Collateral and the final distribution by Fleet National Bank Collateral
Agent of all monies or other property or proceeds constituting the Fleet
National Bank Liquid Collateral in accordance with the terms of the
Participation Agreement.

                6.2     Upon any termination of this Agreement pursuant to
Section 6.1, Lessor and the Fleet National Bank Collateral Agent shall execute
and deliver to or as directed in writing by Lessee, an appropriate instrument
terminating this Agreement and releasing the Fleet National Bank Liquid
Collateral and the Fleet National Bank Collateral Agent shall provide the Fleet
National Bank Custodian with written notice informing the Fleet National Bank
Custodian that the Secured Lessee Obligations have been fully discharged and
instructing the Fleet National Bank Custodian to release all funds on deposit in
the Account (Fleet National Bank) from the assignment and pledge.

                6.3     Except as otherwise provided in this Article 6, this
Agreement and the security interests created hereby shall continue in full force
and effect in accordance with the terms hereof.

                                   ARTICLE 7

                                  MISCELLANEOUS

                7.1     NOTICES

                Notices and other communications required or permitted to be
given or made under the terms of this Agreement shall be given in the manner set
forth in the Participation Agreement at the initial addresses (and any successor
address for notice may be provided in the manner set forth in the Participation
Agreement) set forth on Schedule II to the Participation Agreement.



                                       14
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                7.2     COUNTERPARTS

                This Agreement may be executed by the parties hereto in
separate counterparts, each of which when so executed and delivered shall be an
original, but all such counterparts shall together constitute but one and the
same instrument.

                7.3     CONTINUING SECURITY

                (a)     Except as provided in Article 6, the security
constituted by this Agreement with respect to the Secured Lessee Obligations
shall not be considered as satisfied by payment or satisfaction of any part of
the Secured Lessee Obligations but shall be a continuing security and extend to
cover any and all sums of money or other obligations which shall for the time
being constitute Secured Lessee Obligations and shall not be discharged or
prejudiced or affected in any way by time being given to Lessee or any other
Person or by any other indulgence or concession to Lessee or any other Person
granted by Lessor, Fleet National Bank Collateral Agent or any Beneficiary, by
the taking, holding, varying, non-enforcement or release by Lessor, the Fleet
National Bank Collateral Agent or any Beneficiary of any other security for all
or any of the Secured Lessee Obligations, by any other thing done or omitted or
neglected to be done by Lessor, Fleet National Bank Collateral Agent or any
Beneficiary or by any other dealing or thing including whatsoever that but for
this provision might operate to discharge any of the Secured Lessee Obligations
or to exonerate or discharge Lessee from its obligations hereunder or otherwise
affect the security hereby constituted.

                (b)     Except as provided in Article 6, the security
constituted by this Agreement with respect to the Secured Lessor Obligations
shall not be considered as satisfied by payment or satisfaction of any part of
the Secured Lessor Obligations but shall be a continuing security and extend to
cover any and all sums of money or other obligations which shall for the time
being constitute Secured Lessor Obligations and shall not be discharged or
prejudiced or affected in any way by time being given to Lessor or any other
Person or by any other indulgence or concession to Lessor or any other Person
granted by the Fleet National Bank Collateral Agent or any Beneficiary, by the
taking, holding, varying, non-enforcement or release by the Fleet National Bank
Collateral Agent or any Beneficiary of any other security for all or any of the
Secured Lessor Obligations, by any other thing done or omitted or neglected to
be done by the Fleet National Bank Collateral Agent or any Beneficiary or by any
other dealing or thing including whatsoever that but for this provision might
operate to discharge any of the Secured Lessor Obligations or to exonerate or
discharge Lessor from its obligations hereunder or otherwise affect the security
hereby constituted.

                7.4     AMENDMENTS

                This Agreement may be amended only by a consent in writing
signed by the parties hereto, and specifically identified as an amendment
hereto.

                7.5     SEVERABILITY

                Any provision of this Agreement which is invalid, illegal or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such invalidity, illegality or unenforceability without
invalidating, prohibiting the observance of or rendering


                                       15
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


unenforceable the remaining provisions hereof, and any such invalidity,
illegality or unenforceability in any jurisdiction shall not invalidate,
prohibit the observance of or render unenforceable such provision in any other
jurisdiction.

                7.6     GOVERNING LAW

                THIS AGREEMENT SHALL IN ALL RESPECTS BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK (INCLUDING
SECTION 5-1401 AND 5-1402 OF THE NEW YORK GENERAL OBLIGATIONS LAW BUT EXCLUDING
ALL OTHER CHOICE-OF-LAW AND CONFLICTS-OF-LAWS RULES). THE PARTIES HERETO AGREE
THAT THE STATE OF NEW YORK IS THE JURISDICTION OF THE COLLATERAL AGENT FOR
PURPOSES OF PART 3 OF ARTICLE 9 OF THE UCC.

                Any suit, action or proceeding against the parties hereto with
respect to this Agreement, or any other Operative Document or any judgment
entered by any court in respect thereof may be brought in the Supreme Court of
the State of New York, County of New York, or the United States District Court
for the Southern District of New York (provided that such jurisdiction shall be
non-exclusive). The provisions of Sections 12.13 and 12.14 of the Participation
Agreement and related definitions are incorporated herein by reference, mutatis
mutandis.

                7.7     OWNER

                Lessee acknowledges its ownership of, and its responsibility
(as opposed to Lessor, the Fleet National Bank Collateral Agent or the
Beneficiaries) to pay taxes, if any, imposed on it or with respect to, the Fleet
National Bank Liquid Collateral.

                7.8     ENTIRE AGREEMENT

                This Agreement, and all instruments and other documents
required to be executed and delivered in connection herewith, represents the
entire agreement of the parties hereto and supercedes all prior agreements and
understandings of the parties with respect to the subject matter covered hereby.

                                   ARTICLE 8

                                    PARTIES

                No Person dealing with the Fleet National Bank Collateral
Agent or any Beneficiary is bound to inquire whether an Enforcement Event shall
have occurred or whether the power that the Fleet National Bank Collateral Agent
or any Beneficiary is purporting to exercise has become exercisable or whether
any Secured Lessee Obligations or Secured Lessor Obligations remain unpaid or
unperformed or otherwise as to the propriety or regularity of any sale or other
dealing by the Fleet National Bank Collateral Agent or any Beneficiary with any
Fleet National Bank Liquid Collateral and all the protections to purchasers
conferred by Applicable Law shall apply to such Persons dealing with the Fleet
National Bank Collateral Agent or any Beneficiary. The receipt by the Fleet
National Bank Collateral Agent or any



                                       16
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


Beneficiary of the purchase moneys shall effectively discharge the purchaser who
shall not be concerned with the manner of application thereof.

                                    ARTICLE 9

                                    ELECTION

                So long as Section 6.1(y)(i) of the Participation Agreement does
not require Lessee to secure its Secured Lessee Obligations on the basis of
Properly Margined Liquid Collateral, Lessee shall have the right, upon at least
five Business Days written notice to the Fleet National Bank Collateral Agent
and each of the Participants, to secure its Secured Lessee Obligations on the
basis of either Properly Margined Liquid Collateral or Non-Properly Margined
Liquid Collateral, such change to become effective on the next succeeding
Scheduled Payment Date following such five day notice period.

                            [Signature Pages Follow]


                                       17
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



        IN WITNESS WHEREOF the parties hereto have caused this LIQUID
COLLATERAL AGREEMENT to be fully executed as of the day and year first above
written.

                                 HUMAN GENOME SCIENCES, INC.



                                 By:  /s/ STEVEN C. MAYER
                                      -----------------------------
                                      Name:  Steven C. Mayer
                                      Title: Senior Vice President and CFO



                                      S-1
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 GENOME STATUTORY TRUST 2001A

                                   By:  Wells Fargo Bank Northwest, N.A., not in
                                   its individual capacity but solely as Trustee


                                 By:  /s/ C. SCOTT NIELSON
                                      -----------------------------
                                      Name:  C. Scott Nielson
                                      Title: Vice President


                                      S-2
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 FLEET NATIONAL BANK, as Fleet National
                                 Bank Collateral Agent



                                 By:  /s/ STEVEN CRISCIONE
                                      -----------------------------
                                      Name:  Steven Criscione
                                      Title: Vice President



                                      S-3
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 BENEFICIARIES:



                                 FLEET NATIONAL BANK, as a Liquidity
                                 Provider





                                 By:  /s/ STEVEN CRISCIONE
                                      -----------------------------
                                      Name:  Steven Criscione
                                      Title: Vice President




                                      S-4
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 FIRST UNION NATIONAL BANK, as a Liquidity
                                 Provider





                                 By:  /s/ BARBARA K. ANGEL
                                      -----------------------------
                                      Name:  Barbara K. Angel
                                      Title: Vice President









                                      S-5
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                 BANCBOSTON LEASING INVESTMENTS INC.,
                                 as an Investor





                                 By:  /s/ STEVEN CRISCIONE
                                      -----------------------------
                                      Name:  Steven Criscione
                                      Title: Vice President


                                      S-6
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT




                                 FIRST UNION NATIONAL BANK, as an Investor





                                 By:  /s/ BARBARA K. ANGEL
                                      -----------------------------
                                      Name:  Barbara Kaufmann Angel
                                      Title: Vice President


                                      S-7
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 EAGLEFUNDING CAPITAL CORPORATION, as Conduit





                                 By:  /s/ THOMAS M. CALHOUN
                                      -----------------------------
                                      Name:  Thomas M. Calhoun
                                      Title: Director, its
                                             attorney-in-fact


                                      S-8
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT



                                 FLEET NATIONAL BANK, as Fleet National
                                 Bank Collateral Agent





                                 By:  /s/ STEVEN CRISCIONE
                                      -----------------------------
                                      Name:  Steven Criscione
                                      Title: Vice President



                                      S-9
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                 FIRST UNION NATIONAL BANK, as First Union
                                 Collateral Agent





                                 By:  /s/ BARBARA K. ANGEL
                                      -----------------------------
                                      Name:  Barbara Kaufmann Angel
                                      Title: Vice President


                                      S-10
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                 FLEET NATIONAL BANK, as Administrative Agent





                                 By:  /s/ STEVEN CRISCIONE
                                      -----------------------------
                                      Name:  Steven Criscione
                                      Title: Vice President




                                      S-11
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                                                      SCHEDULE I

                                  Beneficiaries

         1.       Fleet National Bank, as a Liquidity Provider

         2.       First Union National Bank, as a Liquidity Provider

         3.       BancBoston Leasing Investments, Inc., as an Investor

         4.       First Union National Bank, as an Investor

         5.       EagleFunding Capital Corporation, as Conduit

         6.       Fleet National Bank, as Fleet National Bank Collateral Agent

         7.       First Union National Bank, as First Union Collateral Agent

         8.       Fleet National Bank, as Administrative Agent





<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                    EXHIBIT A
                             TO FLEET NATIONAL BANK
                      LIQUID COLLATERAL SECURITY AGREEMENT
                        Description of Pledged Securities


              Designation by Name, Series, Amount and Maturity Date


<TABLE>
<CAPTION>
                                                                             Amount
Name                                               Series                 (At Maturity)          Maturity Date
----                                               ------                 -------------          -------------
<S>                                                <C>                    <C>                   <C>

</TABLE>


                                      Ex.A
<PAGE>
                                 FLEET NATIONAL BANK LIQUID COLLATERAL AGREEMENT


                                    EXHIBIT B

                           Form of Enforcement Notice


 Name and Address of Administrative Agent and Fleet National Bank Custodian


Re:      ENFORCEMENT NOTICE
         Securities Account No. 0006529470 (the "Account (Fleet National Bank)")
         of HUMAN GENOME SCIENCES, INC., as Pledgor (the "Pledgor"), pledged to
         and subject to a first priority security interest in favor of FLEET
         NATIONAL BANK, as Fleet National Bank Collateral Agent (the "Fleet
         National Bank Collateral Agent"), pursuant to the Fleet National Bank
         Liquid Collateral Agreement, dated as of November 7, 2001, among
         Lessee, Lessor, the Fleet National Bank Collateral Agent and the
         Beneficiaries set forth on Schedule I thereto (the "Agreement")
         (capitalized terms used but not otherwise defined herein have the
         respective meanings specified, whether or not by reference, in the
         Agreement)

Ladies and Gentlemen:

                  We hereby demand pursuant to Section 3 of the Custody
Agreement that you take the following action with respect to the Fleet National
Bank Liquid Collateral:

                  [instructions to be provided by Fleet National
                   Bank Collateral Agent]


                                 Very truly yours,

                                 FLEET NATIONAL BANK, as Fleet National
                                 Bank Collateral Agent



                                 By:
                                      -----------------------------
                                          Title:
                                          Date:



                                      Ex.B

<PAGE>




                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                              PAGE
<S>               <C>                                                                                          <C>
ARTICLE 1         DEFINITIONS, INTERPRETATION

         1.1      Certain Definitions............................................................................2

ARTICLE 2         GRANTING OF SECURITY

         2.1      Granting of Security Interests.................................................................4
         2.2      Remedies.......................................................................................8
         2.3      Pledgors Remain Liable.........................................................................9
         2.4      Instructions Regarding the Account (Fleet National Bank) ......................................9
         2.5      Additional Fleet National Bank Liquid Collateral...............................................9

ARTICLE 3         COVENANTS OF LESSEE

         3.1      No Set-off....................................................................................10
         3.2      Further Transfers.............................................................................11

ARTICLE 4         COVENANTS OF LESSOR AND LESSEE

         4.1      No Set-off....................................................................................11
         4.2      Further Transfers.............................................................................11

ARTICLE 5         REMEDIES

         5.1      Remedies Upon Enforcement Event ..............................................................12
         5.2      Powers of Attorney............................................................................13

ARTICLE 6         RELEASE OF SECURITY INTEREST

         6.1      ..............................................................................................15
         6.2      ..............................................................................................15
         6.3      ..............................................................................................15

ARTICLE 7         MISCELLANEOUS

         7.1      Notices.......................................................................................15
         7.2      Counterparts..................................................................................15
         7.3      Continuing Security...........................................................................16
         7.4      Amendments....................................................................................16
         7.5      Severability..................................................................................16
         7.6      Governing Law.................................................................................17
         7.7      Owner.........................................................................................17
         7.8      Entire Agreement..............................................................................17

ARTICLE 8         PARTIES

ARTICLE 9         ELECTION

</TABLE>

                                      -i-
<PAGE>
                               TABLE OF CONTENTS

                                  (continued)


                                                                            PAGE


EXHIBIT A - DESCRIPTION OF SECURITIES

EXHIBIT B - FORM OF ENFORCEMENT NOTICE






                                      -ii-