DATED October 27, 2000



                                (1) TOLERRX, INC.

                          (2) PROFESSOR HERMAN WALDMANN



                              Consulting Agreement

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THIS CONSULTING AGREEMENT ("Agreement") is entered into as of October 27, 2000
("Effective Date") by and between TolerRx, Inc., a Delaware corporation having
its principal place of business at 84 Berkeley St, Boston, Massachusetts,
02116, USA ("Company"), and Herman Waldmann of 4 Apsley Road, Oxford OX27QY.
United Kingdom ("Consultant").

1.   CONSULTING SERVICES

     1.1    Subject to and upon the terms and conditions set forth in this
            Agreement, the Company hereby retains the Consultant, and the
            Consultant hereby agrees to provide to the Company the Consulting
            Services defined in Section 1.2. In rendering the Consulting
            Services hereunder, the Consultant shall act solely as an
            independent contractor, and this Agreement shall not be construed to
            create any employee/employer or principal/agent relationship between
            the Consultant and the Company.

     1.2    During the Term (as defined in Section 4.1 below) of this Agreement,
            it is hereby acknowledged and agreed by the Company and the
            Consultant that the Consultant's consulting services (the
            "Consulting Services") shall be: (i) chairing and attending meetings
            of the Company's Scientific Advisory Board no less than 4 times per
            year and no more than 6 times per year, (ii) serving as a
            nonexecutive member of the Board of Directors, and (iii) such
            consulting and technical advisory services as shall be reasonably
            requested from time to time by the President or the Board of
            Directors of the Company in the field of investigation and
            commercial development of therapies with the intended purpose of
            inducing immunotolerance using antibodies against antigens CD4 and
            CD8 and the regulatory mechanisms associated with these forms of
            immunotolerance ("the Field"). This Field may be changed or expanded
            through a written amendment to this Agreement and subject to the
            consent of the Consultant's employer, the University of Oxford.

     1.3    During the Term of this Agreement, the Consultant will devote the
            time equivalent of fifteen (15) working days per year (which
            includes time spent in attendance at Scientific Advisory Board
            meetings and up to ten (10) visits to the Company) in the
            performance of the Consulting Services.

     1.4    The Consultant shall provide the Consulting Services hereunder at
            such times and locations as are mutually agreed upon by the
            Consultant and the Company; provided, however, that the Consultant
            shall not provide such Consulting Services at the University of
            Oxford, or at the offices or facilities of any future employer of
            the Consultant, or of any other person to whom the Consultant
            provides consulting services, unless otherwise specified in any
            development agreement, license agreement or other agreement between
            the Company, on one hand, and the University of Oxford or such other
            employer or person, on the other hand, or unless the parties agree
            otherwise.

     1.5    It is understood and agreed that, during the Term and subject to the
            provisions of Section 10, the Consultant may not be involved in any
            capacity in other businesses, endeavours and undertakings, except
            for his consulting relationships

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            with Millennium Pharmaceuticals, Inc., Nextran, Inc. and any venture
            capitalist companies or firms and except for his employment role at
            the University of Oxford, and provided that the Consultant may be
            involved with not-for-profit organisations and professional
            societies and may allocate time to academic appointments. In
            addition the Company agrees that the Consultant shall be allowed
            until 31 December 2000 to terminate his consultancies with Peptor,
            Ltd. and XTL Pharmaceuticals and the period until 31 December 2001
            to terminate his consultancy with Xoma Corporation.

     1.6    It is hereby expressly acknowledged and agreed by the Company and
            the Consultant that, in determining and mutually agreeing upon the
            times and locations for the performance by the Consultant of his
            consulting services to the Company, due consideration shall be given
            to the Consultant's commitments to the University of Oxford or any
            future employer of the Consultant or to any of the other permitted
            activities referred to in Section 1.5. The Company shall use its
            best efforts to schedule such times and locations so as to avoid any
            conflict with the Consultant's obligations to the University of
            Oxford or any future employer of the Consultant or any of such other
            business endeavours or undertakings and in relation to the
            Consultant's obligations to the University of Oxford, those
            obligations shall take precedence over obligations to the Company.

2.   COMPENSATION

     2.1    Subject to the provisions of this Section 2.1, the Company shall, so
            long as the Consultant is providing the Consulting Services to the
            Company under this Agreement, pay the Consultant a consulting fee in
            an amount equal to $80,000.00 per year (the "Consulting Fee") which
            amount is to be paid in arrears in equal quarterly instalments,
            commencing within thirty days of the Company receiving proceeds from
            a debt, convertible debt or equity financing of not less than
            $2,000,000.

     2.2    The company will not withhold any tax or Social Security payments
            due from the Consultant to any governmental taxing authority. The
            Consultant hereby agrees that he or she will promptly pay all taxes
            and fees upon the income he or she has earned from the Company, and
            will indemnify and hold the Company harmless against the claims of
            any governmental taxing authority made in connection with the
            revenue derived by the Consultant under this Agreement.

     2.3    Except for the Consulting Fee provided for under this Section 2
            (payment of which is subject to the provisions of Section 2.1) and
            the expense reimbursement provided pursuant to Section 3, the
            Company shall have no obligation to provide any other compensation
            to the Consultant with respect to the Consulting Services rendered
            by the Consultant to the Company.

3.   EXPENSES

     The Company shall reimburse the Consultant for any actual expenses incurred
     by the Consultant while rendering the Consulting Services under this
     Agreement so long as such expenses are reasonable and necessary,
     appropriately documented, and, where feasible, approved in advance by the
     Company.

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4.   TERM; TERMINATION

     4.1    This Agreement shall take effect as of the Effective Date and shall
            continue thereafter in full force and effect until terminated in
            accordance with the provisions of Section 4.2-4.3 or otherwise
            provided that permission for the continuance of this Agreement must
            be obtained from the Consultant's employer in advance on an annual
            basis and failure to obtain such permission shall result in
            termination of this Agreement on the day before the next anniversary
            of this Agreement. For the purposes of this Agreement, the period
            commencing on the Effective Date and ending on the effective date of
            termination shall be referred to as the "Term". The Consultant shall
            begin providing the Consulting Services to the Company on the
            Effective Date.

     4.2    This Agreement and the Consulting Services provided by the
            Consultant hereunder shall terminate immediately upon the
            Consultant's death (but without prejudice to any accrued rights of
            the Consultant).

     4.3    This Agreement and the Consulting Services provided by the
            Consultant hereunder may be terminated at any time by either the
            Consultant or the Company for any reason or no reason by giving at
            least thirty (30) days' prior written notice of termination to the
            other party.

     4.4    The provisions of Sections 5, 6.1, 6.3, 7, 8, 9, 10, 11 and 12 shall
            survive the termination of this Agreement.

5.   CONFIDENTIAL INFORMATION

     5.1    For purposes of this Agreement, the term "Confidential Information"
            shall mean (i) confidential information, knowledge or data of the
            Company; (ii) trade secrets of the Company; and (iii) any other
            information of the Company disclosed to the Consultant or to which
            the Consultant is given access by the Company during the Term.
            Without limiting the generality of the foregoing, the term
            Confidential Information shall include

            5.1.1   all inventions, improvements, developments, ideas,
                    processes, prototypes, plans, drawings, designs, models,
                    formulations, specifications, methods, techniques,
                    shop-practices, discoveries, innovations, creations,
                    technologies, formulae, algorithms, data, computer
                    databases, reports, laboratory notebooks, papers, writings,
                    photographs, source and object codes, software programs,
                    other works of authorship, know-how, patents, trademarks and
                    copyrights (including all records pertaining to any of the
                    foregoing), whether or not reduced to writing and whether or
                    not patented or patentable or registered or registrable
                    under patent, copyright, trademark or similar statute, that
                    are owned by the Company or that are required to be assigned
                    to the Company by any person, including, without limitation,
                    any employee or consultant of the Company, or that are
                    licensed to the Company by any person (collectively,
                    "Inventions");

            5.1.2   information regarding the Company's plans for research and
                    development or for new products;

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            5.1.3   engineering or manufacturing information proprietary to the
                    Company or any of its operations or products;

            5.1.4   information regarding regulatory matters concerning the
                    Company;

            5.1.5   information regarding any acquisition or strategic alliance
                    effected by the Company or any proposed acquisition or
                    strategic alliance being considered by the Company;

            5.1.6   information regarding the status or outcome of any
                    negotiations engaged in by the Company;

            5.1.7   information regarding the existence or terms of any contract
                    entered into by the Company;

            5.1.8   information regarding any aspect of the Company's
                    intellectual property position;

            5.1.9   information regarding prices or costs of the Company;

            5.1.10  information regarding any aspect of the Company's business
                    strategy, including, without limitation, the Company's
                    marketing, selling and distribution strategies;

            5.1.11  information regarding customers or suppliers of the Company;

            5.1.12  information regarding the skills, compensation and other
                    terms of employment or engagement of the Company's employees
                    and consultants;

            5.1.13  business plans, budgets, unpublished financial statements
                    and unpublished financial data of the Company;

            5.1.14  information regarding marketing and sales of any actual or
                    proposed produce or services of the Company; and

            5.1.15  any other information that the Company may designate as
                    confidential.

            Provided that it shall be the Company's responsibility to ensure
            that it has in place and enforces its own systems for maintenance of
            confidentiality in its Confidential Information and that such
            Confidential Information is not disclosed to the Consultant except
            to the extent reasonably necessary to enable him to perform the
            Consulting Services.

     5.2    The Consultant acknowledges that, except to the extent otherwise
            provided in this Section 5.2 or in Section 5.4, all Confidential
            Information disclosed to or acquired by the Consultant may be a
            valuable, special, and unique asset of the Company and is to be held
            in trust by the Consultant for the Company's sole benefit. Except as
            otherwise provided in this Section 5.2 or in Section 5.4, the
            Consultant shall use all reasonable endeavours not to, at any time
            during or after the Term, use for himself or others, or disclose or
            communicate to any person for any reason, any Confidential
            Information without the prior written consent of the Company.
            Notwithstanding anything in this Section 5.2 to the contrary, it is

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            understood that, (i) except to the extent otherwise expressly
            prohibited by the Company the Consultant may disclose or use
            Confidential Information in performing the Consulting Services and
            (ii) the Consultant may disclose any Confidential Information
            pursuant to a request or order of any court or governmental agency,
            provided that, if permitted or not prohibited, the Consultant
            promptly notifies the Company of any such request or order and
            provides reasonable co-operation (at the Company's expense) in the
            efforts, if any, of the Company to contest or limit the scope of
            such request or order.

     5.3    The Consultant acknowledges and agrees that the Company has
            received, and may receive in the future, confidential or proprietary
            information from third parties ("Third Party Confidential
            Information") subject to a duty on the Company's part to maintain
            the confidentiality for such Third Party Confidential Information
            and to use it only for certain limited purposes. During the Term and
            thereafter and provided that such Third Party Confidential
            Information is clearly identified to him prior to its disclosure by
            the Company, the Consultant shall hold Third Party Confidential
            Information in the strictest confidence and will not use or disclose
            to anyone any Third Party Confidential Information, unless expressly
            authorised in writing by the Company or unless otherwise provided
            below in this Section 5.3 or in Section 5.4. Notwithstanding
            anything in this Section 5.3 to the contrary, it is understood that,
            (i) except to the extent otherwise expressly prohibited by the
            Company, the Consultant may disclose or use Confidential Third Party
            Information in performing his Consulting Services for the Company
            but only to the extent required or reasonably necessary for the
            performance of such Consulting Services in the ordinary course and
            within the scope of his Consulting Services and (ii) the Consultant
            may disclose any Third Party Confidential Information pursuant to a
            request or order of any court or governmental agency, provided that,
            if permitted or not prohibited, the Consultant promptly notifies the
            Company of any such request or order and provides reasonable
            co-operation (at the Company's expense) in the efforts, if any, of
            the Company to contest or limit the scope of such request or order.

     5.4    The Consultant's obligations under Sections 5.2 and 5.3 not to use,
            disclose or communicate Confidential Information or Third Party
            Confidential Information to any person without the prior written
            consent of the Company shall not apply to any Confidential
            Information or Third Party Confidential Information which (i) is or
            becomes publicly known under circumstances involving no breach by
            the Consultant of this Agreement or (ii) was or is approved for
            release by the Board or an authorised representative of the Company
            or (iii) is known to the Consultant before the Effective Date, and
            not impressed already with any obligation of confidentiality to the
            Company; or (iv) is independently developed by the Consultant; or
            (v) is obtained by the Consultant from a third party in
            circumstances where the Consultant has no reason to believe that
            there has been a breach of an obligation of confidentiality owed to
            the Company.

6.   NO IMPROPER DISCLOSURE OR USE OF MATERIALS

     6.1    The Consultant shall not improperly use or disclose to or for the
            Company's benefit any confidential information or trade secrets of
            (i) any former, current or future employers, (ii) any person to whom
            the Consultant has previously provided or currently provides
            consulting services or (iii) any other person to

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            whom the Consultant owes an obligation of confidentiality. The
            Consultant shall not bring onto the premises of the Company any
            unpublished documents or any property belonging to any person
            referred to in any of the foregoing clauses (i), (ii) and (iii)
            unless consented to in writing by such person. Without limiting be
            generality of the foregoing, the Consultant shall not disclose to
            the Company, and shall not use for the Company's benefit, any
            information relating to or arising out of his work conducted at the
            University of Oxford, or utilising the funds, personnel, facilities,
            materials or other resources of the University of Oxford, until such
            information has been published; provided, however, that the
            foregoing shall not apply to any and all such information to the
            extent that the Company shall be legally entitled to such
            information pursuant to any license granted by the University of
            Oxford's subsidiary company Isis Innovation Limited to the Company.

     6.2    The Consultant agrees that any property situated on the Company's
            premises, including disks and other storage media, filing cabinets
            or other work areas, is subject to inspection by Company personnel
            at any time with or without notice.

     6.3    The Consultant will promptly deliver to the Company, upon the
            termination of the Consultant's Consulting Services to the Company
            or, if earlier, upon the request of the Company, all documents and
            other tangible media (including all originals, copies,
            reproductions, digests, abstracts, summaries, analyses, notes,
            notebooks, drawings, manuals, memoranda, records, reports, plans,
            specifications, devices, formulas, storage media, including
            software, and computer printouts) in the Consultant's actual or
            constructive possession or control that contain, reflect, disclose
            or directly relate to any Confidential Information, Third Party
            Confidential Information, Assigned Inventions or Proprietary Rights.
            The Consultant will destroy any related computer entries on
            equipment or media not owned by the Company.

7.   INVENTIONS; ASSIGNMENT

     7.1    For purposes of this Agreement, the term "Assigned Inventions"
            (subject to the provisions of Section 7.3) shall mean any and all
            Inventions that (i) are made, conceived, invented, discovered,
            originated, authored, created, learned or reduced to practice by the
            Consultant, either alone or together with others, in the course of
            rendering his Consulting Services hereunder regardless of whether or
            not such Inventions were made, conceived, invented, discovered,
            originated, authored, created, learned or reduced to practice by the
            Consultant at the Company's facilities or during regular business
            hours or utilising resources of the Company or (ii) arise out of or
            are based upon any Confidential Information or Third Party
            Confidential Information. Notwithstanding the foregoing, the term
            Assigned Inventions shall expressly exclude any Inventions in
            relation to which any work is carried out at the university of
            Oxford or using facilities or resources of the University of Oxford.
            For purposes of this Agreement, the term "Proprietary Rights" shall
            mean any and all rights under or in connection with any patents,
            patent applications, copyrights, copyright applications, mask works,
            trade secrets and other intellectual property rights with respect to
            Assigned Inventions.

     7.2    The Consultant hereby agrees to hold any and all Assigned Inventions
            and Proprietary Rights in trust for the sole right and benefit of
            the Company and such

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            other person or persons as the Company shall designate in writing,
            and the Consultant hereby assigns to the Company and such other
            person or persons as the Company shall designate in writing all of
            his right, title and interest in and to any and all Assigned
            Inventions and Proprietary Rights. The Consultant agrees to give the
            Company prompt written notice of any Assigned Invention or
            Proprietary Rights and agrees to execute such instruments of
            transfer. assignment, conveyance of confirmation and such other
            documents as the Company may request to evidence, confirm or perfect
            the assignment of all of the Consultant's right, title and interest
            in and to any Assigned Invention or Proprietary Rights pursuant to
            the foregoing provisions of this Section 7.2. The Consultant hereby
            waives to the Company any and all claims of any nature whatsoever
            that the Consultant may now or hereafter have for infringement of
            any Proprietary Rights assigned hereunder to the Company. The
            obligations of the Consultant under this Section are without
            prejudice, and are in addition to, any other obligations or duties
            of the Consultant, imposed by the applicable law of this Contract,
            to assign to the Company all Assigned Inventions and all Proprietary
            Rights.

     7.3    Notwithstanding anything expressed or implied in Section 7.1 or 7.2
            to the contrary, it is hereby understood and agreed that the
            Consultant is not assigning, and has not agreed to assign, to the
            Company pursuant to this Section 7, and that the term "Assigned
            Inventions" shall not include, any right, title or interest in and
            to any inventions, improvements, developments, ideas, innovations,
            discoveries, designs, creations, processes, methods, techniques,
            technologies, prototypes, models, plans, formulations,
            specifications, shop-practices, formulas, algorithms, data,
            drawings, reports, writings, laboratory notebooks, source and object
            codes, software programs, other works of authorship, product names
            or marks, marketing materials or programs and know-how (including
            all records pertaining to any of the foregoing). Whether or not
            reduced to writing and whether or not patentable or registrable
            under patent, copyright, trademark or similar statues, that are
            made, conceived, invented, discovered, originated, authored,
            created, learned or reduced to practice by the Consultant, either
            alone or together with others, in the course of his research
            activities at the University of Oxford or any other third party or
            through the use of funds, personnel, facilities, materials or other
            resources of the University of Oxford or any other third party. The
            Company hereby expressly acknowledges and agrees that the Consultant
            may have a preexisting obligation to assign to the University of
            Oxford all of his rights to any and all of the items referred to
            above in this Section 7.3.

     7.4    At the request and expense of the Company, the Consultant will
            assist the Company in every proper way (including, without
            limitation, by executing patent applications and assignments of
            patents or copyrights) to obtain and enforce in any country in the
            world Proprietary Rights relating to any or all Assigned Inventions.
            The Consultant's obligation under this Section 7.4 shall continue
            beyond the Term. If and to the extent that, at any time after the
            Term, the Company requests assistance from the Consultant with
            respect to obtaining and enforcing in any country in the world any
            Proprietary Rights relating to Assigned Inventions, the Company
            shall, in addition to bearing expenses, compensate the Consultant at
            a reasonable rate for the time actually spent by the Consultant on
            such assistance.

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     7.5    By this Agreement, the Consultant hereby irrevocably constitutes and
            appoints the Company as his attorney-in-fact for the purpose of
            executing, in the Consultant's name and on his behalf, (i) such
            instruments or other documents as may be necessary to evidence,
            confirm or perfect any assignment pursuant to the provisions of this
            Section 7 or (ii) such applications, certificates, instruments or
            documents as may be necessary to obtain or enforce any Proprietary
            Rights in any country of the world. This power of attorney is
            coupled with an interest on the part of the Company and is
            irrevocable provided that the Company shall give the Consultant
            prior written notice of any such execution in his name or on his
            behalf.

     7.6    Without the prior written consent of the Company, the Consultant
            shall not, at any time, file any patent or copyright application
            with respect to, or claiming, any Assigned Inventions.

8.   AGREEMENT NOT TO COMPETE

     8.1    In view of the nature of the business of the Company and the need of
            the Company to maintain its competitive advantage in the industry,
            the Consultant agrees that, during the Restricted Period (as defined
            in Section 8.2), the Consultant shall not, directly or indirectly,
            within the United States of America or its Territories or
            Possessions or within any other country in the world, engage in, own
            an interest in (except as a holder of no more than one per cent (1%)
            of the shares of any publicly traded corporation), be employed by,
            consult for, act as an advisor to, or otherwise in any way
            participate in or become associated with, any Competitive Business
            (as defined in Section 8.2) or any corporation, partnership, limited
            liability company, business, enterprise, venture or other person or
            entity that is engaged or participates in any Competitive Business
            (each, a "competitive Business Entity"), unless, in each case, the
            Consultant shall have given notice to the Board of Directors of the
            Company of his intention to be employed by, consult for, act as an
            advisor to, or otherwise in any way participate in or become
            associated with, any Competitive Business or any Competitive
            Business Entity and the Board of Directors of the Company shall have
            approved the Consultant's relationship with or engagement in such
            Competitive Business or Competitive Business Entity; provided,
            however, that nothing in this Section 8 shall be construed to limit
            the ability of the Consultant to be employed by, to conduct research
            for, or to engage in research-related activities for, the University
            of Oxford or any sponsor of any research carried out by the
            University of Oxford. During the Restricted Period, the Consultant
            also shall not solicit, or arrange to have any other person or
            entity solicit, any person or entity engaged by the Company as an
            employee, customer or supplier of, or consultant or advisor to, the
            Company to terminate such party's relationship with the Company.

     8.2    For purposes of this Section 8, the following terms shall have the
            meanings provided therefore below:

            "Competitive Business" shall mean any business that involves the
            research, development or commercialisation of any products in the
            Field.

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            "Restricted Period" shall mean the period commencing on the
            Effective Date and ending on the second anniversary of the effective
            date of the termination of the Consulting Services.

     8.3    The time periods provided for in this Section 8 shall be extended
            for a period of time equal to any period of time in which the
            Consultant shall be in violation of any provision of this Section 8
            and any period of time required for litigation to enforce the
            provisions of this Section 8. If at any time the provisions of this
            Section 8 shall be determined to be invalid or unenforceable, by
            reason of being vague or unreasonable as to area, duration or scope
            of activity, this Section 8 shall be considered divisible and scope
            of activity shall be as determined to be reasonable by the court of
            other body having jurisdiction over the matter; and the Consultant
            agrees that this Section 8, as so amended, shall be valid and
            binding as though any invalid or unenforceable provision had not
            been included herein.

9.   NO USE OF NAME, ETC.

     9.1    Without the prior written consent of the Company, the Consultant
            shall not, at any time, use, for himself or on behalf of any other
            person, any name that is identical or similar to or likely to be
            confused with the name of the Company or any product or service
            produced or provided by the Company. Without the prior written
            consent of the Company, the Consultant shall not, at any time after
            the termination of the Consultant's Consulting Services to the
            Company, directly or indirectly represent himself, whether on his
            behalf or on behalf of any other person, as then being in any way
            connected or associated with the Company.

     9.2    Without the prior written consent of the University of Oxford, the
            Company shall not, at any time, use, for itself or on behalf of any
            other person, any name or logo or mark that is identical or similar
            to or likely to be confused with the name of the University of
            Oxford, whether or not such use is in conjunction with the name of
            the Consultant. The provisions of this Section 9.2 are intended to
            confer a right on the University of Oxford pursuant to the Contacts
            (Rights of Third Parties) Act 1999 and may not be amended without
            the prior written consent of the University of Oxford.

10.  NO CONFLICTING OBLIGATION

     The Consultant represents that he is free to enter into this Agreement and
     that his performance of all of the terms of this Agreement and of all of
     his duties as a consultant to the Company do not and will not breach (a)
     any agreement to keep information acquired by the Consultant in confidence
     or in trust, (b) any agreement to assign to any third party inventions made
     by the Consultant or (c) any agreement not to compete against the business
     of any third party. The Consultant further represents that he has not made
     and will not make any agreements in conflict with this Agreement. The
     Consultant hereby further represents to the Company that he has provided to
     the Company true, correct and complete copies of (i) all relevant sections
     of written agreements between the Consultant and the University of Oxford
     and (ii) any written documents known to the Consultant that set forth the
     rights and responsibilities of, or the restrictions imposed upon, faculty
     members of the University of Oxford with respect to the involvement by such
     faculty members in consulting activities outside of the University of
     Oxford.

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11.  LIABILITY

     The liability of either party for any breach of this Agreement, or arising
     in any other way out of the subject matter of this Agreement, will not
     extend to loss of business or profit or any incidental or consequential
     damages or losses. In any event, the Company accepts and agrees that the
     Consultant's maximum liability under or otherwise in connection with this
     Agreement or its subject matter shall not exceed the amount of the
     compensation which he has received under section 2.

12.  MISCELLANEOUS

     12.1   ENTIRE AGREEMENT. This Agreement represents the entire Agreement of
            the parties with respect to the arrangements contemplated hereby. No
            prior agreement, whether written or oral, shall be construed to
            change, amend, alter, repeal or invalidate this Agreement. This
            Agreement may be amended only by a written instrument executed in
            one or more counterparts by the parties.

     12.2   WAIVER. No consent to or waiver of any breach or default in the
            performance of any obligations hereunder shall be deemed or
            construed to be a consent to or waiver of any other breach or
            default in the performance of any of the same or any other
            obligations hereunder. Failure on the part of either party to
            complain of any act or failure to act of the other party or to
            declare the other party in default, irrespective of the duration of
            such failure, shall not constitute a waiver of rights hereunder and
            no waiver hereunder shall be effective unless it is in writing,
            executed by the party waiving the breach or default hereunder.

     12.3   ASSIGNMENT. This Agreement shall be binding upon and inure to the
            benefit of the parties hereto and their respective successors and
            permitted assigns. This Agreement may be assigned by the Company to
            any affiliate of the Company and to a successor of its business to
            which this Agreement relates (whether by purchase of otherwise).
            "Affiliate of the Company" means any person which directly or
            indirectly, controls or is controlled by or is under common control
            with the Company and, for the purposes of this definition, "control"
            (including the terms "controlled by" and "under common control
            with") shall mean the possession, directly or indirectly, of the
            power to direct or cause the direction of the management and
            policies of another whether through the ownership or voting
            securities or holding of office in another, by contract or
            otherwise. The Consultant may not assign or transfer any or all of
            his rights or obligations under this Agreement.

     12.4   Except as stated in clauses 1.6, 6.1, 7.1, and 9.2 (which are
            intended to be enforceable by the University of Oxford and which may
            not be amended or affected by any other amendment or any term to
            this Agreement without the prior written consent of the University
            of Oxford), the parties to this Agreement do not intend that by
            virtue of the Contracts (Rights of Third Parties) Act 1999 any of
            the terms of this Agreement should be enforceable by a person who is
            not a party to it.

     12.5   NOTICES. Any notices required or permitted hereunder shall be given
            to the recipient in person or shall be delivered to such recipient
            at the address which

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            appears above or at such other address as the recipient shall
            specify in writing or, in the case of the University of Oxford to:

                  The Director,
                  Research Services Office
                  University of Oxford
                  University Offices
                  Wellington Square
                  Oxford
                  OX1 2JD

            Such notice shall be deemed given upon delivery to the recipient in
            person or upon personal delivery to the recipient's appropriate
            address or, if sent by certificate or registered mail, three days
            after the date of mailing.

     12.6   GOVERNING LAW. This Agreement shall be governed by and construed
            in accordance with the laws of England and the English Courts shall
            have exclusive jurisdiction to hear any matters arising at, or in
            connection with this Agreement. Section headings of this Agreement
            are for reference only and shall not affect its interpretation. In
            the event that any provision of this Agreement should be held
            unenforceable by a court of competent jurisdiction, such court is
            hereby authorised to amend such provision so as to be enforceable to
            the fullest extent permitted by law, and all remaining provisions
            shall continue in full force without being impaired or invalidated
            in any way.

     12.7   COUNTERPARTS. This Agreement may be executed in counterparts, all of
            which together shall for all purposes constitute one agreement
            binding on each of the parties hereto notwithstanding that each such
            party shall not have signed the same counterpart.

     12.8   ACKNOWLEDGEMENT. THE CONSULTANT UNDERSTANDS THAT THIS AGREEMENT
            AFFECTS HIS RIGHTS TO ASSIGNED INVENTIONS, AND RESTRICTS CONSULTANTS
            RIGHTS TO DISCLOSE OR USE CONFIDENTIAL INFORMATION OR THIRD PARTY
            CONFIDENTIAL INFORMATION OR TO COMPETE WITH THE COMPANY DURING THE
            RESTRICTED PERIOD.

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IN WITNESS WHEREOF, the parties have signed this Agreement as of the date
written above intending it to take effect as a sealed instrument.


SIGNED for and on behalf of
TOLERRX, INC.


By:       /s/ Douglas J. Ringler
   -----------------------------------
Douglas J. Ringler, President


CONSULTANT

     /s/ Herman Waldmann
--------------------------------------
Herman Waldmann

Source: OneCLE Business Contracts.