Document:

QuickLinks
 -- Click here to rapidly navigate through this document

Exhibit 10.21  

 
 

TRUST COMMON SECURITIES GUARANTEE AGREEMENT
  American Equity Investment Life Holding Company    
    
    Dated as of October 29, 1999    
    

  

 
 

TABLE OF CONTENTS    
    

	 
	 	 
	 	Page

	 	 	ARTICLE I

DEFINITIONS AND INTERPRETATION	 	 
	

Section 1.1	
 	

Definitions and Interpretation	
 	

1
	

 	
 	

ARTICLE II

TRUST INDENTURE ACT	
 	

 
	

Section 2.1	
 	

Trust Indenture Act; Application	
 	

4
	Section 2.2	 	Lists of Holders of Securities	 	4
	Section 2.3	 	Reports by the Common Guarantee Trustee	 	4
	Section 2.4	 	Periodic Reports to Common Guarantee Trustee	 	4
	Section 2.5	 	Evidence of Compliance with Conditions Precedent	 	4
	Section 2.6	 	Events of Default; Waiver	 	4
	Section 2.7	 	Event of Default; Notice	 	5
	Section 2.8	 	Conflicting Interests	 	5
	

 	
 	

ARTICLE III

POWERS, DUTIES AND RIGHTS OF COMMON GUARANTEE TRUSTEE	
 	

 
	

Section 3.1	
 	

Powers and Duties of the Common Guarantee Trustee	
 	

5
	Section 3.2	 	Certain Rights of Common Guarantee Trustee	 	6
	Section 3.3	 	Not Responsible for Recitals or Issuance of Trust Common Securities Guarantee	 	8
	

 	
 	

ARTICLE IV

COMMON GUARANTEE TRUSTEE	
 	

 
	

Section 4.1	
 	

Common Guarantee Trustee; Eligibility	
 	

8
	Section 4.2	 	Appointment, Removal and Resignation of Common Guarantee Trustees	 	9
	

 	
 	

ARTICLE V

TRUST COMMON SECURITIES GUARANTEE	
 	

 
	

Section 5.1	
 	

Trust Common Securities Guarantee	
 	

9
	Section 5.2	 	Subordination	 	9
	Section 5.3	 	Waiver of Notice and Demand	 	9
	Section 5.4	 	Obligations Not Affected	 	10
	Section 5.5	 	Rights of Holders	 	10
	Section 5.6	 	Guarantee of Payment	 	11
	Section 5.7	 	Subrogation	 	11
	Section 5.8	 	Independent Obligations	 	11
	

 	
 	

ARTICLE VI

LIMITATION OF TRANSACTIONS; SUBORDINATION	
 	

 
	

Section 6.1	
 	

Limitation of Transactions	
 	

11
	Section 6.2	 	Ranking	 	12
	

 	
 	

ARTICLE VII

TERMINATION	
 	

 
	

Section 7.1	
 	

Termination	
 	

12
	 	 	 	 	 

i

 

	

 	
 	

ARTICLE VIII

INDEMNIFICATION	
 	

 
	

Section 8.1	
 	

Exculpation	
 	

12
	Section 8.2	 	Indemnification	 	12
	

 	
 	

ARTICLE IX

MISCELLANEOUS	
 	

 
	

Section 9.1	
 	

Successors and Assigns	
 	

13
	Section 9.2	 	Amendments	 	13
	Section 9.3	 	Notices	 	13
	Section 9.4	 	Benefit	 	14
	Section 9.5	 	Governing Law	 	14

ii

 
 

TRUST COMMON SECURITIES GUARANTEE AGREEMENT    
    

        This TRUST COMMON SECURITIES GUARANTEE AGREEMENT (this "Trust Common Securities Guarantee"), dated as of October 29, 1999, is executed and delivered by
American Equity Investment Life Holding Company, an Iowa corporation (the "Guarantor"), and West Des Moines State Bank, an Iowa banking corporation, as trustee (the "Common Guarantee Trustee"), for
the benefit of the Holders (as defined herein) from time to time of the Trust Common Securities (as defined herein) of American Equity Capital Trust II, a Delaware statutory business trust (the
"Trust"). 

        WHEREAS,
pursuant to an Amended and Restated Declaration of Trust, dated as of October 29, 1999 (the "Declaration"), among the trustees of the Trust named therein, the Guarantor,
as sponsor, and the holders from time to time of undivided beneficial interests in the assets of the Trust, the Trust is issuing on the date hereof 3,000 common securities, having an aggregate
liquidation amount of $3,000,000 designated the "Trust Common Securities" (the "Trust Common Securities"); 

        WHEREAS,
as incentive for the Holders to purchase the Trust Common Securities, the Guarantor desires irrevocably and unconditionally to agree, to the extent set forth in this Trust
Common Securities Guarantee, to guarantee the obligations of the Trust to the Holders of Trust Common Securities on the terms and conditions set forth herein; and 

        WHEREAS,
the Guarantor is also executing and delivering a guarantee agreement (the "Trust Preferred Securities Guarantee") in substantially identical terms to this Trust Common
Securities Guarantee for the benefit of the holders of the Trust Preferred Securities (as defined herein), except that if an Indenture Event of Default (as defined herein) has occurred and is
continuing, the rights of holders of the Trust Common Securities to receive Guarantee Payments (as defined herein) under the Trust Common Securities Guarantee shall be subordinated to the rights of
Holders of Trust Preferred Securities to receive Guarantee Payments (as defined in the Trust Preferred Securities Guarantee) under this Trust Common Securities Guarantee; 

        NOW,
THEREFORE, in consideration of the purchase by each Holder of Trust Common Securities, which purchase the Guarantor hereby agrees shall benefit the Guarantor, the Guarantor executes
and delivers this Trust Common Securities Guarantee for the benefit of the Holders. 

 
 

ARTICLE I    
    
    DEFINITIONS AND INTERPRETATION    
    

        Section
1.1    Definitions and Interpretation.    

        In
this Trust Common Securities Guarantee, unless the context otherwise requires: 

        (a)   capitalized
terms used in this Trust Common Securities Guarantee but not defined in the preamble above have the respective meanings assigned to them in this
Section 1.1; 

        (b)   terms
defined in the Declaration as at the date hereof have the same meaning when used in this Trust Common Securities Guarantee unless otherwise defined in the Trust
Common Securities Guarantee; 

        (c)   a
term defined anywhere in this Trust Common Securities Guarantee has the same meaning throughout; 

        (d)   all
references to "the Trust Common Securities Guarantee" or "this Trust Common Securities Guarantee" are to this Trust Common Securities Guarantee as modified,
supplemented or amended from time to time; 

        (e)   all
references in this Trust Common Securities Guarantee to Articles and Sections are to Articles and Sections of this Trust Common Securities Guarantee, unless
otherwise specified; 

        (f)    a
term defined in the Trust Indenture Act has the same meaning when used in this Trust Common Securities Guarantee, unless otherwise defined in this Trust Common
Securities Guarantee or unless the context otherwise requires; 

 

        (g)   a
reference to the singular includes the plural and vice versa; 

        (h)   a
reference to any Person shall include its successors and assigns; 

        (i)    a
reference to any agreement or instrument shall mean such agreement or instrument, as supplemented, modified, amended, or amended and restated, and in effect from time
to time; and 

        (j)    a
reference to any statute, law, rule or regulation, shall include any amendments thereto applicable to the relevant Person, and any successor statute, law, rule or
regulation. 

        "Affiliate"
has the same meaning as given to that term in Rule 405 of the Securities Act of 1933, as amended, or any successor rule thereunder. 

        "Business
Day" means any day other than a Saturday, Sunday or day on which banking institutions in West Des Moines, Iowa or in Wilmington, Delaware are authorized or required by any
applicable law or executive order to close. 

        "Common
Guarantee Trustee" means West Des Moines State Bank, until a Successor Common Guarantee Trustee has been appointed and has accepted such appointment pursuant to the terms of this
Trust Common Securities Guarantee and thereafter means each such Successor Common Guarantee Trustee. 

        "Common
Stock" means the common stock, par value $1.00 per share, of the Guarantor. 

        "Corporate
Trust Office" means the office of the Common Guarantee Trustee at which the corporate trust business of the Common Guarantee Trustee shall, at any particular time, be
principally administered, which office at the date of execution of this Agreement is located at West Des Moines State Bank, 1601 22nd Street, West Des Moines, Iowa 50266, Attention:
Corporate Trust Administration. 

        "Covered
Person" means any Holder or beneficial owner of Trust Common Securities. 

        "Debentures"
means the 5% Subordinated Debentures due 2047 of the Guarantor held by the Property Trustee (as defined in the Declaration). 

        "Event
of Default" means a default by the Guarantor on any of its payment or other obligations under this Trust Common Securities Guarantee. 

        "Guarantee
Payments" means the following payments or distributions, without duplication, with respect to the Trust Common Securities, to the extent not paid or made by the Trust:
(i) any accrued and unpaid Distributions (as defined in the Declaration) that are required to be paid on such Trust Common Securities to the extent the Trust shall have funds available
therefor, (ii) the redemption price, including all accrued and unpaid Distributions to the date of redemption (the "Redemption Price"), with respect to any Trust Common Securities called for
redemption by the Trust to the extent the Trust has funds available therefor, and (iii) upon a voluntary or involuntary dissolution, winding-up or termination of the Trust (other
than in connection with a distribution of the Debentures to the Holders in exchange for Trust Common Securities or the redemption of all of the Trust Common Securities as provided in the Declaration),
the lesser of (a) the aggregate of the total liquidation amount and all accrued and unpaid Distributions on the Trust Common Securities to the date of payment, to the extent the Trust shall
have funds available therefor, and (b) the amount of assets of the Trust remaining available for distribution to Holders upon liquidation of the Trust (in either case, the "Liquidation
Distribution"). If an Indenture Event of Default has occurred and is continuing, the rights of holders of the Trust Common Securities to receive Guarantee Payments under this Trust Common Securities
Guarantee are subordinate to the rights of Holders of Trust Preferred Securities to receive Guarantee Payments under the Trust Preferred Securities Guarantee. 

        "Holder"
shall mean any holder, as registered on the books and records of the Trust, of any Trust Common Securities; provided, however, that in determining whether the holders of the
requisite 

2

 

percentage
of Trust Common Securities have given any request, notice, consent or waiver hereunder, "Holder" shall not include the Guarantor or any Affiliate of the Guarantor. 

        "Indemnified
Person" means the Common Guarantee Trustee, any Affiliate of the Common Guarantee Trustee, or any officers, directors, shareholders, members, partners, employees,
representatives, nominees, custodians or agents of the Common Guarantee Trustee. 

        "Indenture"
means the Indenture, dated as of October 29, 1999, among the Guarantor and West Des Moines State Bank, an Iowa banking corporation, as trustee, pursuant to which the
Debentures are to be issued to the Property Trustee of the Trust. 

        "Indenture
Event of Default" means an "Indenture Event of Default" as defined in the Indenture. 

        "Indenture
Trustee" means the Person acting as trustee under the Indenture, initially West Des Moines State Bank, Iowa. 

        "Majority
in liquidation amount of the Trust Common Securities" means, except as provided by the Trust Indenture Act, a vote by Holder(s) of Trust Common Securities, voting separately as
a class, of more than 50% of the liquidation amount (including the stated amount that would be paid on redemption, liquidation or otherwise, plus accrued and unpaid Distributions to the date upon
which the voting percentages are determined) of all Trust Common Securities. 

        "Officers'
Certificate" means, with respect to any Person, a certificate signed by two Authorized Officers of such Person. Any Officers' Certificate delivered with respect to compliance
with a condition or covenant provided for in this Trust Common Securities Guarantee shall include: 

        (a)   a
statement that each officer signing the Officers' Certificate has read the covenant or condition and the definition relating thereto; 

        (b)   a
brief statement of the nature and scope of the examination or investigation undertaken by each officer in rendering the Officers' Certificate; 

        (c)   a
statement that each such officer has made such examination or investigation as, in such officer's opinion, is necessary to enable such officer to express an informed
opinion as to whether or not such covenant or condition has been complied with; and 

        (d)   a
statement as to whether, in the opinion of each such officer, such condition or covenant has been complied with. 

        "Person"
means a legal person, including any individual, corporation, estate, partnership, joint venture, association, joint stock company, limited liability company, trust,
unincorporated association, or government or any agency or political subdivision thereof, or any other entity of whatever nature. 

        "Responsible
Officer" means, with respect to the Common Guarantee Trustee, any officer within the Corporate Trust Office of the Common Guarantee Trustee, including any vice president,
any assistant vice president, any assistant secretary, the treasurer, any assistant treasurer or other officer of the Corporate Trust Office of the Common Guarantee Trustee customarily performing
functions similar to those performed by any of the above designated officers and also means, with respect to a particular corporate trust matter, any other officer to whom such matter is referred
because of that officer's knowledge of and familiarity with the particular subject. 

        "Successor
Common Guarantee Trustee" means a successor Common Guarantee Trustee possessing the qualifications to act as Common Guarantee Trustee under Section 4.1. 

        "Trust
Indenture Act" means the Trust Indenture Act of 1939, as amended. 

        "Trust
Preferred Securities" means the securities representing preferred undivided beneficial interests in the assets of the Trust. 

3

 

 
 

ARTICLE II    
    
    TRUST INDENTURE ACT    
    

        Section
2.1    Trust Indenture Act; Application.    

        (a)   This
Trust Common Securities Guarantee is subject to the provisions of the Trust Indenture Act that would be required to be part of this Trust Common Securities
Guarantee were this Trust Common Securities Guarantee to be qualified under the Trust Indenture Act, which provisions are incorporated by reference in and made part of this Trust Common Securities
Guarantee and this Trust Common Securities Guarantee shall, to the extent applicable, be governed by such provisions; and 

        (b)   if
and to the extent that any provision of this Trust Common Securities Guarantee limits, qualifies or conflicts with the duties imposed by Sections 310 to 317,
inclusive, of the Trust Indenture Act, such imposed duties shall control. 

        Section
2.2    Lists of Holders of Securities.    

        (a)   The
Guarantor shall provide the Common Guarantee Trustee with a list, in such form as the Common Guarantee Trustee may reasonably require, of the names and addresses of
the Holders of the Trust Common Securities ("List of Holders") as of such date, (i) within 14 days after each record date for payment of Distributions, and (ii) at any other time
within 30 days of receipt by the Trust of a written request for a List of Holders as of a date no more than 14 days before such List of Holders is given to the Common Guarantee Trustee,
provided that the Guarantor shall not be obligated to provide such List of Holders at any time the List of Holders does not differ from the most recent List of Holders given to the Common Guarantee
Trustee by the Guarantor. The Common Guarantee Trustee may destroy any List of Holders previously given to it on receipt of a new List of Holders. 

        (b)   The
Common Guarantee Trustee shall comply with its obligations under Section 311(a), 311(b) and Section 312(b) of the Trust Indenture Act. 

        Section
2.3    Reports by the Common Guarantee Trustee.    Within 60 days after December 31of each year,
the Common Guarantee Trustee shall provide to the Holders of the Trust Common Securities such reports as are required by Section 313 of the Trust Indenture Act, if any, in the form and in the
manner provided by Section 313 of the Trust Indenture Act. The Common Guarantee Trustee shall also comply with the requirements of Section 313(d) of the Trust Indenture Act. 

        Section
2.4    Periodic Reports to Common Guarantee Trustee.    The Guarantor shall provide to the Common Guarantee
Trustee such documents, reports and information as required by Section 314 (if any) and the compliance certificate required by Section 314 of the Trust Indenture Act in the form, in the
manner and at the times required by Section 314 of the Trust Indenture Act. 

        Section
2.5    Evidence of Compliance with Conditions Precedent.    The Guarantor shall provide to the Common
Guarantee Trustee such evidence of compliance with any conditions precedent, if any, provided for in this Trust Common Securities Guarantee that relate to any of the matters set forth in
Section 314(c) of the Trust Indenture Act. Any certificate or opinion required to be given by an officer pursuant to Section 314(c)(1) may be given in the form of an Officers'
Certificate. 

        Section
2.6    Events of Default; Waiver.    The Holders of a Majority in liquidation amount of Trust Common
Securities may, by vote, on behalf of the Holders of all of the Trust Common Securities, waive any past Event of Default and its consequences. Upon such waiver, any such Event of Default shall cease
to exist, and any Event of Default arising therefrom shall be deemed to have been cured, for every purpose of this Trust Common Securities Guarantee, but no such waiver shall extend to any subsequent
or other default or Event of Default or impair any right consequent thereon. 

4

 

        Section
2.7    Event of Default; Notice.    

        (a)   The
Common Guarantee Trustee shall, within 90 days after the occurrence of an Event of Default, transmit by mail, first class postage prepaid, to the Holders of
the Trust Common Securities, notices of all Events of Default of which the Common Guarantee Trustee is deemed to have knowledge (as defined in Section 2.7(b)), unless such defaults have been
cured before the giving of such notice; provided that the Common Guarantee Trustee shall be protected in withholding such notice if and so long as a Responsible Officer of the Common Guarantee Trustee
in good faith determines that the withholding of such notice is in the interests of the Holders of the Trust Common Securities. 

        (b)   The
Common Guarantee Trustee shall be deemed to have knowledge of an Event of Default if (i) the Common Guarantee Trustee shall have received written notice of
such Event of Default or (ii) a Responsible Officer of the Common Guarantee Trustee charged with the administration of the Declaration shall have obtained actual knowledge of such Event of
Default. 

        Section
2.8    Conflicting Interests.    The Declaration shall be deemed to be specifically described in this Trust
Common Securities Guarantee for the purposes of clause (i) of the first proviso contained in Section 310(b) of the Trust Indenture Act. 

 
 

ARTICLE III    
    
    POWERS, DUTIES AND RIGHTS
  OF COMMON GUARANTEE TRUSTEE    
    

        Section
3.1    Powers and Duties of the Common Guarantee Trustee.    

        (a)   This
Trust Common Securities Guarantee shall be held by the Common Guarantee Trustee for the benefit of the Holders of the Trust Common Securities, and the Common
Guarantee Trustee shall not transfer this Trust Common Securities Guarantee to any Person except a Holder of Trust Common Securities exercising his or her rights pursuant to Section 5.5(b) or
to a Successor Common Guarantee Trustee on acceptance by such Successor Common Guarantee Trustee of its appointment to act as Successor Common Guarantee Trustee. The right, title and interest of the
Common Guarantee Trustee shall automatically vest in any Successor Common Guarantee Trustee, and such vesting and cessation of title shall be effective whether or not conveyancing documents have been
executed and delivered pursuant to the appointment of such Successor Common Guarantee Trustee. 

        (b)   If
an Event of Default of which the Common Guarantee Trustee is deemed to have knowledge (as defined in Section 2.7(b)) has occurred and is continuing, the Common
Guarantee Trustee shall enforce this Trust Common Securities Guarantee for the benefit of the Holders of the Trust Common Securities. 

        (c)   The
Common Guarantee Trustee, before the occurrence of any Event of Default and after the curing of all Events of Default that may have occurred, shall undertake to
perform only such duties as are specifically set forth in this Trust Common Securities Guarantee, and no implied covenants shall be read into this Trust Common Securities Guarantee against the Common
Guarantee Trustee. In case an Event of Default has occurred (that has not been cured or waived pursuant to Section 2.6) and of which the Common Guarantee Trustee is deemed to have knowledge (as
defined in Section 2.7(b)), the Common Guarantee Trustee shall exercise such of the rights and powers vested in it by this Trust Common Securities Guarantee, and use the same degree of care and
skill in its exercise thereof, as a prudent person would exercise or use under the circumstances in the conduct of such person's own affairs. 

5

 

        (d)   No
provision of this Trust Common Securities Guarantee shall be construed to relieve the Common Guarantee Trustee from liability for its own negligent action, its own
negligent failure to act, or its own willful misconduct, except that: 

          (i)  prior
to the occurrence of any Event of Default and after the curing or waiving of all such Events of Default that may have occurred: 

        (A)  the
duties and obligations of the Common Guarantee Trustee shall be determined solely by the express provisions of this Common Securities Guarantee, and the Common
Guarantee Trustee shall not be liable except for the performance of such duties and obligations as are specifically set forth in this
Trust Common Securities Guarantee, and no implied covenants or obligations shall be read into this Trust Common Securities Guarantee against the Common Guarantee Trustee; and 

        (B)  in
the absence of bad faith on the part of the Common Guarantee Trustee, the Common Guarantee Trustee may conclusively rely, as to the truth of the statements and the
correctness of the opinions expressed therein, upon any certificates or opinions furnished to the Common Guarantee Trustee and conforming to the requirements of this Trust Common Securities Guarantee;
but in the case of any such certificates or opinions that by any provision hereof are specifically required to be furnished to the Common Guarantee Trustee, the Common Guarantee Trustee shall be under
a duty to examine the same to determine whether or not they conform to the requirements of this Trust Common Securities Guarantee; 

         (ii)  the
Common Guarantee Trustee shall not be liable for any error of judgment made in good faith by a Responsible Officer of the Common Guarantee Trustee, unless it shall
be proved that the Common Guarantee Trustee was negligent in ascertaining the pertinent facts upon which such judgment was made; 

        (iii)  the
Common Guarantee Trustee shall not be liable with respect to any action taken or omitted to be taken by it in good faith in accordance with the direction of the
Holders of not less than a Majority in liquidation amount of the Trust Common Securities relating to the time, method and place of conducting any proceeding for any remedy available to the Common
Guarantee Trustee, or exercising any trust or power conferred upon the Common Guarantee Trustee under this Trust Common Securities Guarantee; and 

        (iv)  no
provision of this Trust Common Securities Guarantee shall require the Common Guarantee Trustee to expend or risk its own funds or otherwise incur personal financial
liability in the performance of any of its duties or in the exercise of any of its rights or powers, if the Common Guarantee Trustee shall have reasonable grounds for believing that the repayment of
such funds or liability is not reasonably assured to it under the terms of this Trust Common Securities Guarantee or indemnity, reasonably satisfactory to the Common Guarantee Trustee, against such
risk or liability is not reasonably assured to it. 

        Section
3.2    Certain Rights of Common Guarantee Trustee.    

        (a)   Subject
to the provisions of Section 3.1: 

          (i)  The
Common Guarantee Trustee may conclusively rely, and shall be fully protected in acting or refraining from acting upon, any resolution, certificate, statement,
instrument, opinion, report, notice, request, direction, consent, order, bond, debenture, note, other evidence of indebtedness or other paper or document believed by it to be genuine and to have been
signed, sent or presented by the proper party or parties. 

         (ii)  Any
direction or act of the Guarantor contemplated by this Trust Common Securities Guarantee shall be sufficiently evidenced by an Officers' Certificate. 

6

 

        (iii)  Whenever,
in the administration of this Trust Common Securities Guarantee, the Common Guarantee Trustee shall deem it desirable that a matter be proved or established
before taking, suffering or omitting any action hereunder, the Common Guarantee Trustee (unless other evidence is herein specifically prescribed) may, in the absence of bad faith on its part, request
and conclusively rely upon an Officers' Certificate which, upon receipt of such request, shall be promptly delivered by the Guarantor. 

        (iv)  The
Common Guarantee Trustee shall have no duty to see to any recording, filing or registration of any instrument (or any rerecording, refiling or registration
thereof). 

         (v)  The
Common Guarantee Trustee may consult with counsel of its selection, and the written advice or opinion of such counsel with respect to legal matters shall be full and
complete authorization and protection in respect of any action taken, suffered or omitted by it hereunder in good faith and in accordance with such advice or opinion. Such counsel may be counsel to
the Guarantor or any of its Affiliates and may include any of its employees. The Common Guarantee Trustee shall have the right at any time to seek instructions concerning the administration of this
Trust Common Securities Guarantee from any court of competent jurisdiction. 

        (vi)  The
Common Guarantee Trustee shall be under no obligation to exercise any of the rights or powers vested in it by this Trust Common Securities Guarantee at the request
or direction of any Holder, unless such Holder shall have provided to the Common Guarantee Trustee such security and indemnity, reasonably satisfactory to the Common Guarantee Trustee, against the
costs, expenses (including attorneys' fees and expenses) and liabilities that might be incurred by it in complying with such request or direction, including such reasonable advances as may be
requested by the Common Guarantee Trustee; provided that nothing contained in this Section 3.2(a)(vi) shall be taken to relieve the Common Guarantee Trustee, upon the occurrence of an
Event of Default, of its obligation to exercise the rights and powers vested in it by this Trust Common Securities Guarantee. 

       (vii)  The
Common Guarantee Trustee shall not be bound to make any investigation into the facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture, note, other evidence of indebtedness or other paper or document, but the Common Guarantee Trustee, in its discretion, may
make such further inquiry or investigation into such facts or matters as it may see fit. 

      (viii)  The
Common Guarantee Trustee may execute any of the trusts or powers hereunder or perform any duties hereunder either directly or by or through agents, nominees,
custodians or attorneys, and the Common Guarantee Trustee shall not be responsible for any misconduct or negligence on the part of any agent or attorney appointed with due care by it hereunder. 

        (ix)  Any
action taken by the Common Guarantee Trustee or its agents hereunder shall bind the Holders of the Trust Common Securities, and the signature of the Common
Guarantee Trustee or its agents alone shall be sufficient and effective to perform any such action. No third party shall be required to inquire as to the authority of the Common Guarantee Trustee to
so act or as to its compliance with any of the terms and provisions of this Trust Common Securities Guarantee, both of which shall be conclusively evidenced by the Common Guarantee Trustee's or its
agent's taking such action. 

7

  

         (x)  Whenever
in the administration of this Trust Common Securities Guarantee the Common Guarantee Trustee shall deem it desirable to receive instructions with respect to
enforcing any remedy or right or taking any other action hereunder, the Common Guarantee Trustee (i) may request instructions from the Holders of a Majority in liquidation amount of the Trust
Common Securities, (ii) may refrain from enforcing such remedy or right or taking such other action until such instructions are received, and (iii) shall be protected in conclusively
relying on or acting in accordance with such instructions. 

        (xi)  The
Common Guarantee Trustee shall not be liable for any action taken, suffered, or omitted to be taken by it in good faith and reasonably believed by it to be
authorized or within the discretion or rights or powers conferred upon it by this Trust Common Securities Guarantee. 

        (b)   No
provision of this Trust Common Securities Guarantee shall be deemed to impose any duty or obligation on the Common Guarantee Trustee to perform any act or acts or
exercise any right, power, duty or obligation conferred or imposed on it in any jurisdiction in which it shall be illegal, or in which the Common Guarantee Trustee shall be unqualified or incompetent
in accordance with applicable law to perform any such act or acts or to exercise any such right, power, duty or obligation. No permissive power or authority available to the Common Guarantee Trustee
shall be construed to be a duty. 

        Section
3.3    Not Responsible for Recitals or Issuance of Trust Common Securities Guarantee.    The recitals
contained in this Trust Common Securities Guarantee shall be taken as the statements of the Guarantor, and the Common Guarantee Trustee does not assume any responsibility for their correctness. The
Common Guarantee Trustee makes no representation as to the validity or sufficiency of this Trust Common Securities Guarantee. 

 
 

ARTICLE IV    
    
    COMMON GUARANTEE TRUSTEE    
    

        Section
4.1    Common Guarantee Trustee; Eligibility.    

        (a)   There
shall at all times be a Common Guarantee Trustee which shall: 

          (i)  not
be an Affiliate of the Guarantor; and 

         (ii)  be
a corporation organized and doing business under the laws of the United States of America or any State or Territory thereof or of the District of Columbia, or a
corporation or Person permitted by the Securities and Exchange Commission to act as an institutional trustee under the Trust Indenture Act, authorized under such laws to exercise corporate trust
powers, having a combined capital and surplus of at least 50 million U.S. dollars ($50,000,000), and subject to supervision or examination by Federal, State, Territorial or District of Columbia
authority. If such corporation publishes reports of condition at least annually, pursuant to law or to the requirements of the supervising or examining authority referred to above, then, for the
purposes of this Section 4.1(a)(ii), the combined capital and surplus of such corporation shall be deemed to be its combined capital and surplus as set forth in its most recent report of
condition so published. 

        (b)   If
at any time the Common Guarantee Trustee shall cease to be eligible to so act under Section 4.1(a), the Common Guarantee Trustee shall immediately resign in
the manner and with the effect set out in Section 4.2(c). 

        (c)   If
the Common Guarantee Trustee has or shall acquire any "conflicting interest" within the meaning of Section 310(b) of the Trust Indenture Act, the Common
Guarantee Trustee and 

8

 

Guarantor
shall in all respects comply with the provisions of Section 310(b) of the Trust Indenture Act. 

        Section
4.2    Appointment, Removal and Resignation of Common Guarantee Trustees.    

        (a)   Subject
to Section 4.2(c), the Common Guarantee Trustee may be appointed or removed without cause at any time by the Guarantor. 

        (b)   Subject
to Section 4.2(c), the Common Guarantee Trustee may resign from office (without need for prior or subsequent accounting) by an instrument in writing
executed by the Common Guarantee Trustee and delivered to the Guarantor. 

        (c)   The
Common Guarantee Trustee shall hold office and shall not be removed in accordance with Section 4.2(a) or resign in accordance with Section 4.2(b)
unless and until a Successor Common
Guarantee Trustee has been appointed and has accepted such appointment by written instrument executed by such Successor Common Guarantee Trustee and delivered to the Guarantor and, in the case of a
resignation in accordance with Section 4.2(b), the resigning Common Guarantee Trustee. 

        (d)   If
no Successor Common Guarantee Trustee shall have been appointed and accepted appointment as provided in this Section 4.2 within 60 days after delivery
to the Guarantor of an instrument of removal or resignation, the resigning or removed Common Guarantee Trustee may petition any court of competent jurisdiction for appointment of a Successor Common
Guarantee Trustee. Such court may thereupon, after prescribing such notice, if any, as it may deem proper, appoint a Successor Common Guarantee Trustee. 

        (e)   No
Common Guarantee Trustee shall be liable for the acts or omissions to act of any Successor Common Guarantee Trustee. 

        (f)    Upon
termination of this Trust Common Securities Guarantee or removal or resignation of the Common Guarantee Trustee pursuant to this Section 4.2, the Guarantor
shall pay to the Common Guarantee Trustee all amounts accrued to the date of such termination, removal or resignation. 

 
 

ARTICLE V    
    
    TRUST COMMON SECURITIES GUARANTEE    
    

        Section
5.1    Trust Common Securities Guarantee.    The Guarantor irrevocably and unconditionally agrees to pay in
full to the Holders the Guarantee Payments (without duplication of amounts theretofore paid by the Trust), as and when due, regardless of any defense, right of set-off or counterclaim that
the Trust may have or assert. The Guarantor's obligation to make a Guarantee Payment may be satisfied by direct payment of the required amounts by the Guarantor to the Holders or by causing the Trust
to pay such amounts to the Holders. 

        Section
5.2    Subordination.    If an Indenture Event of Default has occurred and is continuing, the rights of
holders of Trust Common Securities to receive Guarantee Payments under this Trust Common Securities Guarantee are subordinate to the rights of Holders of Trust Preferred Securities to receive
Guarantee Payments under the Trust Preferred Securities Guarantee. 

        Section
5.3    Waiver of Notice and Demand.    The Guarantor hereby waives notice of acceptance of this Trust Common
Securities Guarantee and of any liability to which it applies or may apply, presentment, demand for payment, any right to require a proceeding first against the Trust or any other Person before
proceeding against the Guarantor, protest, notice of nonpayment, notice of dishonor, notice of redemption and all other notices and demands. 

9

 

        Section
5.4    Obligations Not Affected.    The obligations, covenants, agreements and duties of the Guarantor under
this Trust Common Securities Guarantee shall in no way be affected or impaired by reason of the happening from time to time of any of the following: 

        (a)   the
release or waiver, by operation of law or otherwise, of the performance or observance by the Trust of any express or implied agreement, covenant, term or condition
relating to the Trust Common Securities to be performed or observed by the Trust; 

        (b)   the
extension of time for the payment by the Trust of all or any portion of the Distributions, Redemption Price, Liquidation Distribution or any other sums payable under
the terms of the Trust Common Securities or the extension of time for the performance of any other obligation under, arising out of, or in connection with, the Trust Common Securities (other than an
extension of time for payment of Distributions, Redemption Price, Liquidation Distribution or other sum payable that results from the extension of any interest payment period on the Debentures or any
extension of the maturity date of the Debentures permitted by the Indenture); 

        (c)   any
failure, omission, delay or lack of diligence on the part of the Holders to enforce, assert or exercise any right, privilege, power or remedy conferred on the
Holders pursuant to the terms of the Trust Common Securities, or any action on the part of the Trust granting indulgence or extension of any kind; 

        (d)   the
voluntary or involuntary liquidation, dissolution, sale of any collateral, receivership, insolvency, bankruptcy, assignment for the benefit of creditors,
reorganization, arrangement, composition or readjustment of debt of, or other similar proceedings affecting, the Trust or any of the assets of the Trust; 

        (e)   any
invalidity of, or defect or deficiency in, the Trust Common Securities; 

        (f)    the
settlement or compromise of any obligation guaranteed hereby or hereby incurred; or 

        (g)   any
other circumstance whatsoever that might otherwise constitute a legal or equitable discharge or defense of a guarantor, it being the intent of this
Section 5.4 that the obligations of the Guarantor hereunder shall be absolute and unconditional under any and all circumstances. 

        There
shall be no obligation of the Holders to give notice to, or obtain consent of, the Guarantor with respect to the happening of any of the foregoing. 

        Section
5.5    Rights of Holders.    

        (a)   The
Holders of a Majority in liquidation amount of the Trust Common Securities have the right to direct the time, method and place of the conducting of any proceeding
for any remedy available to the Common Guarantee Trustee in respect of this Trust Common Securities Guarantee or exercising any trust or power conferred upon the Common Guarantee Trustee under this
Trust Common Securities Guarantee. 

        (b)   Any
Holder of Trust Common Securities may institute a legal proceeding against the Guarantor to enforce the obligations of the Guarantor under this Trust Common
Securities Guarantee without first instituting a legal proceeding against the Trust, the Common Guarantee Trustee or any other Person. 

        (c)   If
an Indenture Event of Default constituting the failure to pay interest, principal or premium, if any, on the Debentures on the date such interest, principal or
premium, if any, is otherwise payable has occurred and is continuing, then a Holder of Trust Common Securities may directly, at any time on or after the respective due date specified in the Debentures
for such payment, institute a proceeding for enforcement of payment to such Holder of the interest, principal or premium, if any, on the Debentures having a principal amount equal to the aggregate
liquidation amount of the Trust Common Securities of such Holder. The Holders of Trust 

10

 

Common
Securities will not be able to exercise directly any other remedy available to the holders of the Debentures unless the Property Trustee (as defined in the Indenture) fails to do so. 

        Section
5.6    Guarantee of Payment.    This Trust Common Securities Guarantee creates a guarantee of payment and not
of collection. 

        Section
5.7    Subrogation.    The Guarantor shall be subrogated to all (if any) rights of the Holders of Trust Common
Securities against the Trust in respect of any amounts paid to such Holders by the Guarantor under this Trust Common Securities Guarantee; provided, however, that the Guarantor shall not
(except to the extent required by mandatory provisions of law) be entitled to enforce or exercise any right that it may acquire by way of subrogation or any indemnity, reimbursement or other
agreement, in all cases as a result of payment under this Trust Common Securities Guarantee, if, at the time of any such payment, any amounts are due and unpaid under this Trust Common Securities
Guarantee. If any amount shall be paid to the Guarantor in violation of the preceding sentence, the Guarantor agrees to hold such amount in trust for the Holders and to pay over such amount to the
Holders. 

        Section
5.8    Independent Obligations.    The Guarantor acknowledges that its obligations hereunder are independent
of the obligations of the Trust with respect to the Trust Common Securities, and that the Guarantor shall be liable as principal and as debtor hereunder to make Guarantee Payments pursuant to the
terms of this Trust Common Securities Guarantee notwithstanding the occurrence of any event referred to in subsections (a) through (g), inclusive, of Section 5.4 hereof. 

 
 

ARTICLE VI    
    
    LIMITATION OF TRANSACTIONS; SUBORDINATION    
    

        Section
6.1    Limitation of Transactions.    So long as any Trust Common Securities remain outstanding, if
(i) the Guarantor has exercised its option to defer interest payments on the Debentures by extending the interest payment period and such extension shall be continuing, (ii) the
Guarantor shall be in default with respect to its payment or other obligations under the Guarantee or (iii) there shall have occurred and be continuing any event that, with the giving of notice
or the lapse of time or both, would constitute an Indenture Event of Default, then the Guarantor shall not (a) declare or pay dividends on, or make a distribution with respect to, or redeem or
purchase or acquire, or make a liquidation payment with respect to, any of its capital stock (other than (1) purchases or acquisitions of shares of Company Common Stock (or Company Common Stock
equivalents) in connection with the satisfaction by the Guarantor of its obligations under any employee benefit or agent plans or the satisfaction by the Guarantor of its obligations pursuant to any
contract or security requiring the Guarantor to purchase shares of Company Common Stock (or Company Common Stock equivalents), (2) purchases of shares of Company Common Stock (or Company Common
Stock equivalents) from officers or employees of the Guarantor or its subsidiaries upon termination of employment or retirement not pursuant to any obligation under any contract or security requiring
the Guarantor to purchase shares of Company Common Stock (or Company Common Stock equivalents), (3) as a result of a reclassification of the Guarantor's capital stock or the exchange or
conversion of one class or series of the Guarantor's capital stock for another class or series of the Guarantor's capital stock, (4) dividends or distributions of shares of Company Common Stock
on Company Common Stock or (5) the purchase of fractional interests in shares of the Guarantor's capital stock pursuant to the conversion or exchange provisions of such capital stock or the
security being converted or exchanged), (b) make any payment of principal of (premium, if any) or interest on or repay, repurchase or redeem any debt securities (including guarantees) issued by
the Guarantor that rank pari passu with or junior to the Debentures and (c) make any guarantee payments with respect to any of the foregoing
(other than pursuant to the Guarantee). 

11

 

        Section
6.2    Ranking.    

        (a)   This
Trust Common Securities Guarantee will constitute an unsecured obligation of the Guarantor and will rank (i) senior to the Guarantor's common stock,
(ii) pari passu with the most senior preferred or preference securities now or hereafter issued by the Guarantor and with any guarantee now or
hereafter entered into by the Guarantor with respect to any preferred or preference securities of the Guarantor or any Affiliate of the Guarantor, and (iii) junior and subordinate in right of
payment to all other liabilities of the Guarantor except any liabilities that may be pari passu expressly by their terms. 

        (b)   The
holders of any obligations of the Guarantor that are senior in priority to the obligations under this Trust Common Securities Guarantee will be entitled to all of
the rights inuring to the holders of "Senior Debt" under Article 12 of the Indenture, and the Holders of the Trust Common Securities will be subject to all of the terms and conditions of such
Article 12 with respect to any claims or rights hereunder with the same effect as though fully set forth herein. 

 
 

ARTICLE VII    
    
    TERMINATION    
    

        Section
7.1    Termination.    This Trust Common Securities Guarantee shall terminate as to each Holder of Trust
Common Securities upon (i) full payment of the applicable Redemption Price (as defined in the Declaration) with respect to all Trust Common Securities, (ii) the distribution of the
Debentures held by the Trust to the Holders of all of the Trust Common Securities of the Trust or (iii) liquidation of the Trust, and will terminate completely upon full payment of the amounts
payable in accordance with the Declaration of the Trust. Notwithstanding the foregoing, this Trust Common Securities Guarantee will continue to be effective or will be reinstated, as the case may be,
if at any time any Holder of Trust Common Securities must restore payment of any sums paid under the Trust Common Securities or under this Trust Common Securities Guarantee. 

 
 

ARTICLE VIII    
    
    INDEMNIFICATION    
    

        Section
8.1    Exculpation.    

        (a)   No
Indemnified Person shall be liable, responsible or accountable in damages or otherwise to the Guarantor or any Covered Person for any loss, damage or claim incurred
by reason of any act or omission performed or omitted by such Indemnified Person in good faith in accordance with this Trust Common Securities Guarantee and in a manner that such Indemnified Person
reasonably believed to be within the scope of the authority conferred on such Indemnified Person by this Trust Common Securities Guarantee or by law, except that an Indemnified Person shall be liable
for any such loss, damage or claim incurred by reason of such Indemnified Person's negligence or willful misconduct with respect to such acts or omissions. 

        (b)   An
Indemnified Person shall be fully protected in relying in good faith upon the records of the Guarantor and upon such information, opinions, reports or statements
presented to the Guarantor by any Person as to matters the Indemnified Person reasonably believes are within such other Person's
professional or expert competence and who has been selected with reasonable care by or on behalf of the Guarantor, including information, opinions, reports or statements as to the value and amount of
the assets, liabilities, profits, losses, or any other facts pertinent to the existence and amount of assets from which Distributions to Holders of Trust Common Securities might properly be paid. 

        Section
8.2    Indemnification.    The Guarantor agrees to indemnify each Indemnified Person for, and to hold each
Indemnified Person harmless against, any loss, liability or expense incurred without 

12

 

negligence
or bad faith on its part, arising out of or in connection with the acceptance or administration of the trust or trusts hereunder, including the costs and expenses (including reasonable
legal fees and expenses) of defending itself against, or investigating, any claim or liability in connection with the exercise or performance of any of its powers or duties hereunder. The obligation
to indemnify as set forth in this Section 8.2 shall survive the termination of this Trust Common Securities Guarantee. 

 
 

ARTICLE IX    
    
    MISCELLANEOUS    
    

        Section
9.1    Successors and Assigns.    All guarantees and agreements contained in this Trust Common Securities
Guarantee shall bind the successors, assigns, receivers, trustees and representatives of the Guarantor and shall inure to the benefit of the Holders of the Trust Common Securities then outstanding.
Except in connection with any merger or consolidation of the Guarantor with or into another entity or any sale, transfer or lease of the Guarantor's assets to another entity, each as permitted by the
Indenture, the Guarantor may not assign its rights or delegate its obligations under this Trust Common Securities Guarantee without the prior approval of the Holders of at least a Majority in
liquidation amount of the Trust Common Securities. 

        Section
9.2    Amendments.    Except with respect to any changes that do not materially adversely affect the rights of
Holders (in which case no consent of Holders will be required), this Trust Common Securities Guarantee may be amended only with the prior approval of the Holders of at least a Majority in liquidation
amount of the Trust Common Securities. The provisions of Section 12.2 of the Declaration with respect to meetings of Holders of the Trust Common Securities apply to the giving of such approval. 

        Section
9.3    Notices.    All notices provided for in this Trust Common Securities Guarantee shall be in writing,
duly signed by the party giving such notice, and shall be delivered, sent by facsimile or mailed by registered or certified mail, as follows: 

        (a)   if
given to the Common Guarantee Trustee, at the Common Guarantee Trustee's mailing address set forth below (or such other address as the Common Guarantee Trustee may
give notice of to the Holders of the Trust Common Securities): 

West
Des Moines State Bank

601 22nd Street

West Des Moines, Iowa 50266

Attention: Corporate Trust Administration 

        (b)   if
given to the Guarantor, at the Guarantor's mailing address set forth below (or such other address as the Guarantor may give notice of to the Holders of the Trust
Common Securities): 

American
Equity Investment Life Holding Company

5000 Westown Parkway, Suite 440

West Des Moines, Iowa 50266

Attention: Chief Financial Officer 

        (c)   If
given to any Holder of Trust Common Securities, at the address set forth on the books and records of the Trust. 

        All
such notices shall be deemed to have been given when received in person, telecopied with receipt confirmed, or mailed by first class mail, postage prepaid except that if a notice or
other document is refused delivery or cannot be delivered because of a changed address of which no notice was given, such notice or other document shall be deemed to have been delivered on the date of
such refusal or inability to deliver. 

13

 

        Section
9.4    Benefit.    This Trust Common Securities Guarantee is solely for the benefit of the Holders of the
Trust Common Securities and, subject to Section 3.1(a), is not separately transferable from the Trust Common Securities. 

        Section
9.5    Governing Law.    THIS TRUST COMMON SECURITIES GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED AND
INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF IOWA AND ALL RIGHTS AND REMEDIES SHALL BE GOVERNED BY SUCH LAWS WITHOUT REGARD TO ITS PRINCIPLES OF CONFLICTS OF LAWS. 

14

        THIS
TRUST COMMON SECURITIES GUARANTEE is executed as of the day and year first above written. 

	 	AMERICAN EQUITY INVESTMENT LIFE HOLDING COMPANY
	

 	

By:	
 	

/s/  DEBRA J. RICHARDSON      

	 	Name:	 	Debra J. Richardson
	 	Title:	 	Sr. VP & Secty.
	

 	

WEST DES MOINES STATE BANK,

as Common Guarantee Trustee
	

 	

By:	
 	

/s/  DAVID V. MAURER      

	 	Name:	 	David V. Maurer
	 	Title:	 	SVP/STO

QuickLinks

TRUST COMMON SECURITIES GUARANTEE AGREEMENT American Equity Investment Life Holding Company Dated as of October 29, 1999

TABLE OF CONTENTS

TRUST COMMON SECURITIES GUARANTEE AGREEMENT

ARTICLE I DEFINITIONS AND INTERPRETATION

ARTICLE II TRUST INDENTURE ACT

ARTICLE III POWERS, DUTIES AND RIGHTS OF COMMON GUARANTEE TRUSTEE

ARTICLE IV COMMON GUARANTEE TRUSTEE

ARTICLE V TRUST COMMON SECURITIES GUARANTEE

ARTICLE VI LIMITATION OF TRANSACTIONS; SUBORDINATION

ARTICLE VII TERMINATION

ARTICLE VIII INDEMNIFICATION

ARTICLE IX MISCELLANEOUS<Page>

                                                                    EXHIBIT 10.1

                                  TOLERRX, INC.

                              AMENDED AND RESTATED
                           2000 EQUITY INCENTIVE PLAN

1.   PURPOSE

     This Plan is intended to encourage ownership of Common Stock by employees,
consultants and directors of the Company and its Affiliates and to provide
additional incentive for them to promote the success of the Company's business.
The Plan is intended to be an incentive stock option plan within the meaning of
Section 422 of the Code but not all Awards granted hereunder are required to be
Incentive Options.

2.   DEFINITIONS

     As used in the Plan the following terms shall have the respective meanings
set out below, unless the context clearly requires otherwise:

     2.1.  ACCELERATE, ACCELERATED, and ACCELERATION, when used with respect to
an Option, means that as of the time of reference such Option will become
exercisable with respect to some or all of the shares of Common Stock for which
it was not then otherwise exercisable by its terms, and, when used with respect
to Restricted Stock, means that the Risk of Forfeiture otherwise applicable to
such Common Stock shall expire with respect to some or all of the shares of
Restricted Stock then still otherwise subject to the Risk of Forfeiture.

     2.2.  ACQUIRING PERSON means, with respect to any Transaction or any
acquisition described in clause (ii) of the definition of Change of Control, the
surviving or acquiring person or entity in connection with such Transaction or
acquisition, as the case may be, PROVIDED THAT if such surviving or acquiring
person or entity is controlled, directly or indirectly, by any other person or
entity (an "ULTIMATE PARENT ENTITY") that is not itself controlled by any entity
or person that is not a natural person, the term "ACQUIRING PERSON" shall mean
such Ultimate Parent Entity.

     2.3.  AFFILIATE means, with respect to any person or entity, any other
person or entity controlling, controlled by or under common control with the
first person or entity.

     2.4.  AWARD means any grant or sale pursuant to the Plan of Options,
Restricted Stock, or Stock Grants.

     2.5.  AWARD AGREEMENT means an agreement between the Company and the
recipient of an Award, setting forth the terms and conditions of the Award.

<Page>

                                      - 2 -

     2.6.  BENEFICIAL OWNERSHIP has the meaning ascribed to such term in Rule
13d-3, or any successor rule thereto, promulgated by the Securities and Exchange
Commission pursuant to the Exchange Act.

     2.7.  BOARD means the Company's Board of Directors.

     2.8.  CHANGE OF CONTROL means (i) the closing of any Sale of the Company
Transaction or (ii) the direct or indirect acquisition, in a single transaction
or a series of related transactions, by any person or Group (other than the
Company or a Controlled Affiliate of the Company) of Beneficial Ownership of
previously outstanding shares of capital stock of the Company if (A) immediately
after such acquisition, such person or Group, together with their respective
Affiliates, shall own or hold shares of capital stock of the Company possessing
at least twenty-five percent (25%) of the total voting power of the outstanding
capital stock of the Company, (B) immediately prior to such acquisition, such
person or Group, together with their respective Affiliates, did not own or hold
shares of capital stock of the Company possessing at least twenty-five percent
(25%) of the total voting power of the outstanding capital stock of the Company,
and (C) within thirty (30) days after the Company is notified or first becomes
aware of such acquisition, whichever is earlier, a majority of the members of
the Board of Directors of the Company as constituted immediately prior to such
acquisition do not consent in writing to exclude such acquisition from the scope
of this definition.

     2.9.  CODE means the Internal Revenue Code of 1986, as amended from time to
time, or any successor statute thereto, and any regulations issued from time to
time thereunder.

     2.10. CONTROLLED AFFILIATE means, with respect to any person or entity, any
other person or entity that is controlled by such person or entity.

     2.11. COMMITTEE means any committee of the Board delegated responsibility
by the Board for the administration of the Plan, as provided in Section 5 of the
Plan. For any period during which no such committee is in existence, "Committee"
shall mean the Board and all authority and responsibility assigned the Committee
under the Plan shall be exercised, if at all, by the Board.

     2.12. COMMON STOCK means common stock, par value $0.001 per share, of the
Company.

     2.13. COMPANY means TolerRx, Inc., a corporation organized under the laws
of the State of Delaware.

     2.14. EXCHANGE ACT means the Securities Exchange Act of 1934, as amended.

     2.15. GRANT DATE means the date as of which an Option is granted, as
determined under Section 7.1(a).

<Page>

                                      - 3 -

     2.16. GROUP has the meaning ascribed to such term in Section 13(d)(3) of
the Exchange Act or any successor section thereto.

     2.17. INCENTIVE OPTION means an Option which by its terms is to be treated
as an "incentive stock option" within the meaning of Section 422 of the Code.

     2.18. MARKET VALUE means the value of a share of Common Stock on any date
as determined by the Committee.

     2.19. NONSTATUTORY OPTION means any Option that is not an Incentive Option.

     2.20. OPTION means an option to purchase shares of Common Stock.

     2.21. OPTIONEE means a Participant to whom an Option shall have been
granted under the Plan.

     2.22. PARTICIPANT means any holder of an outstanding Award under the Plan.

     2.23. PLAN means this Amended and Restated 2000 Equity Incentive Plan of
the Company, as amended and in effect from time to time.

     2.24. RESTRICTED STOCK means a grant or sale of shares of Common Stock to a
Participant subject to a Risk of Forfeiture.

     2.25. RESTRICTION PERIOD means the period of time, established by the
Committee in connection with an Award of Restricted Stock, during which the
shares of Restricted Stock are subject to a Risk of Forfeiture described in the
applicable Award Agreement.

     2.26. RISK OF FORFEITURE means a limitation on the right of a Participant
to retain an Award of Restricted Stock, including a right in the Company to
reacquire such Restricted Stock at less than its then Market Value, arising
because of the occurrence or non-occurrence of specified events or conditions.

     2.27. SALE OF THE COMPANY TRANSACTION means any Transaction in which the
stockholders of the Company immediately prior to such Transaction, together with
any and all of such stockholders' Affiliates, do not own or hold, immediately
after consummation of such Transaction, shares of capital stock of the Acquiring
Person in connection with such Transaction possessing at least a majority of the
total voting power of the outstanding capital stock of such Acquiring Person.

     2.28. SECURITIES ACT means the Securities Act of 1933, as amended.

     2.29. STOCK GRANT means the grant of shares of Common Stock not subject to
restrictions or other forfeiture conditions.

     2.30. TEN PERCENT OWNER means a person who owns, or is deemed within the
meaning of Section 422(b)(6) of the Code to own, stock possessing more than 10%
of the total combined voting power of all classes of stock of the Company (or
any parent or

<Page>

                                      - 4 -

subsidiary corporations of the Company, as defined in Section 424(e) and (f),
respectively, of the Code). Whether a person is a Ten Percent Owner shall be
determined with respect to each Option based on the facts existing immediately
prior to the Grant Date of such Option.

     2.31. TRANSACTION means any merger or consolidation of the Company with or
into another person or entity or the sale or transfer of all or substantially
all of the assets of the Company, in each case in a single transaction or in a
series of related transactions.

3.   TERM OF THE PLAN

     Unless the Plan shall have been earlier terminated by the Board, Awards may
be granted under this Plan at any time in the period commencing on the effective
date of approval of the Plan by the Board and ending immediately prior to the
tenth anniversary of the earlier of the adoption of the Plan by the Board or
approval of the Plan by the Company's stockholders. Awards granted pursuant to
the Plan within such period shall not expire solely by reason of the termination
of the Plan. Awards of Incentive Options granted prior to stockholder approval
of the Plan are hereby expressly conditioned upon such approval, but in the
event of the failure of the stockholders to approve the Plan shall thereafter
and for all purposes be deemed to constitute Nonstatutory Options.

4.   STOCK SUBJECT TO THE PLAN

     Subject to adjustment in accordance with the provisions of Section 8 of the
Plan, the aggregate number of shares of Common Stock that may initially be
issued pursuant to or subject to outstanding Awards granted under the Plan
will not exceed 3,000,000. Notwithstanding the foregoing, and subject to
adjustment in accordance with the provisions of Section 8 of the Plan, no
more than an aggregate of 5,000,000 shares of Stock may be issued pursuant to
the exercise of Incentive Stock Options granted under the Plan. For purposes
of applying the foregoing limitations, if any Option expires, terminates, or
is cancelled for any reason without having been exercised in full, or if any
Award of Restricted Stock is forfeited by the recipient, the shares not
purchased by the Optionee or forfeited by the recipient shall again be
available for Awards thereafter to be granted under the Plan. Shares of
Common Stock issued pursuant to the Plan may be either authorized but
unissued shares or shares held by the Company in its treasury.

5.   ADMINISTRATION

     The Plan shall be administered by the Committee; PROVIDED, HOWEVER, that at
any time and on any one or more occasions the Board may itself exercise any of
the powers and responsibilities assigned the Committee under the Plan and when
so acting shall have

<Page>

                                      - 5 -

the benefit of all of the provisions of the Plan pertaining to the Committee's
exercise of its authorities hereunder; AND PROVIDED FURTHER that the Committee
may delegate to an executive officer or officers the authority to grant Awards
hereunder to employees who are not officers, and to consultants, in accordance
with such guidelines as the Committee shall set forth at any time or from time
to time. Subject to the provisions of the Plan, the Committee shall have
complete authority, in its discretion, to make or to select the manner of making
all determinations with respect to each Award to be granted by the Company under
the Plan in addition to any other determination allowed the Committee under the
Plan including, without limitation: (a) the employee, consultant or director to
receive the Award; (b) the form of Award; (c) whether an Option (if granted to
an employee) will be an Incentive Option or a Nonstatutory Option; (d) the time
of granting an Award; (e) the number of shares subject to an Award; (f) the
exercise price of an Option or purchase price for shares of Restricted Stock or
for a Stock Grant and the method of payment of such exercise price or such
purchase price; (g) the term of an Option; (h) the vesting period of shares of
Restricted Stock and any acceleration thereof; (i) the exercise date or dates of
an Option and any acceleration thereof; and (j) the effect of termination of any
employment, consulting or Board member relationship with the Company or any of
its Affiliates on the subsequent exercisability of an Option or on the Risk of
Forfeiture of Restricted Stock. In making such determinations, the Committee may
take into account the nature of the services rendered by the respective
employees, consultants and directors, their present and potential contributions
to the success of the Company and its Affiliates, and such other factors as the
Committee in its discretion shall deem relevant. Subject to the provisions of
the Plan, the Committee shall also have complete authority to interpret the
Plan, to prescribe, amend and rescind rules and regulations relating to it, to
determine the terms and provisions of the respective Award Agreements (which
need not be identical), and to make all other determinations necessary or
advisable for the administration of the Plan. The Committee's determinations
made in good faith on matters referred to in this Plan shall be final, binding
and conclusive on all persons having or claiming any interest under the Plan or
an Award made pursuant to hereto.

6.   AUTHORIZATION AND ELIGIBILITY

     The Committee may grant from time to time and at any time prior to the
termination of the Plan one or more Awards, either alone or in combination with
any other Awards, to any employee of or consultant to one or more of the Company
and its Affiliates or to any non-employee member of the Board or of any board of
directors (or similar governing authority) of any Affiliate. However, only
employees of the Company, and of any parent or subsidiary corporations of the
Company, as defined in Sections 424(e) and (f), respectively, of the Code, shall
be eligible for the grant of an Incentive Option. Further, in no event shall the
number of shares of Common Stock covered by Options or other Awards granted to
any one person in any one calendar year (or portion of a year) ending after such
date exceed thirty (30%) of the aggregate number of shares of Common Stock
subject to the Plan.

<Page>

                                      - 6 -

     Each grant of an Award shall be subject to all applicable terms and
conditions of the Plan (including but not limited to any specific terms and
conditions applicable to that type of Award set out in the following Section),
and such other terms and conditions, not inconsistent with the terms of the
Plan, as the Committee may prescribe. No prospective Participant shall have any
rights with respect to an Award, unless and until such Participant has executed
an agreement evidencing the Award, delivered a fully executed copy thereof to
the Company, and otherwise complied with the applicable terms and conditions of
such Award.

7.   SPECIFIC TERMS OF AWARDS

     7.1.  OPTIONS.

           (a)  DATE OF GRANT. The granting of an Option shall take place at the
time specified in the Award Agreement. Only if expressly so provided in the
applicable Award Agreement shall the Grant Date be the date on which the Award
Agreement shall have been duly executed and delivered by the Company and the
Optionee.

           (b)  EXERCISE PRICE. The price at which shares of Common Stock may be
acquired under each Incentive Option shall be not less than 100% of the Market
Value of Common Stock on the Grant Date, or not less than 110% of the Market
Value of Common Stock on the Grant Date if the Optionee is a Ten Percent Owner.
The price at which shares may be acquired under each Nonstatutory Option shall
not be so limited solely by reason of this Section.

           (c)  OPTION PERIOD. No Incentive Option may be exercised on or after
the tenth anniversary of the Grant Date, or on or after the fifth anniversary of
the Grant Date if the Optionee is a Ten Percent Owner. The Option period under
each Nonstatutory Option shall not be so limited solely by reason of this
Section.

           (d)  EXERCISABILITY. An Option may be immediately exercisable or
become exercisable in such installments, cumulative or non-cumulative, as the
Committee may determine. In the case of an Option not otherwise immediately
exercisable in full, the Committee may Accelerate such Option in whole or in
part at any time; PROVIDED, HOWEVER, that in the case of an Incentive Option,
any such Acceleration of such Incentive Option would not cause such Incentive
Option to fail to comply with the provisions of Section 422 of the Code or the
Optionee consents to such Acceleration.

           (e)  EFFECT OF TERMINATION OF EMPLOYMENT, CONSULTING OR BOARD MEMBER
RELATIONSHIP. Unless the Committee shall provide otherwise with respect to any
Option, if the Optionee's employment, consulting or Board member relationship
with the Company and its Affiliates ends for any reason, including because an
entity with which the Optionee has an employment, consulting or Board member
relationship ceases to be an Affiliate of the Company, any outstanding Option
held by the Optionee shall cease to be exercisable in any respect not later than
ninety (90) days following that event and, for the period it remains exercisable
following that event, shall be exercisable only to the extent exercisable at the
date of that event. Military or sick leave or other bona fide leave

<Page>

                                      - 7 -

shall not be deemed a termination of employment, PROVIDED that it does not
exceed the longer of ninety (90) days or the period during which the absent
Optionee's reemployment rights, if any, are guaranteed by statute or by
contract.

           (f)  TRANSFERABILITY. Except as otherwise provided in this subsection
(f), Options shall not be transferable, and no Option or interest therein may be
sold, transferred, pledged, assigned, or otherwise alienated or hypothecated,
other than by will or by the laws of descent and distribution. Except as
otherwise provided in this subsection (f), all of a Participant's rights in any
Option may be exercised during the life of the Participant only by the
Participant or the Participant's legal representative. However, the Committee
may, at or after the grant of a Nonstatutory Option, provide that such Option
may be transferred by the recipient to a family member; PROVIDED, HOWEVER, that
any such transfer is without payment of any consideration whatsoever and that no
transfer of an Option shall be valid unless first approved by the Committee,
acting in its sole discretion. For this purpose, "family member" means any
child, stepchild, grandchild, parent, stepparent, spouse, former spouse,
sibling, niece, nephew, mother-in-law, father-in-law, son-in-law,
daughter-in-law, brother-in-law, or sister-in-law, including adoptive
relationships, any person sharing the Participant's household (other than a
tenant or employee), a trust in which the foregoing persons have more than fifty
percent (50%) of the beneficial interests, a foundation in which the foregoing
persons (or the Participant) control the management of assets, and any other
entity in which these persons (or the Participant) own more than fifty percent
(50%) of the voting interests.

           (g)  METHOD OF EXERCISE. An Option may be exercised by the Optionee
giving written notice, in the manner provided in Section 15, specifying the
number of shares of Common Stock with respect to which the Option is then being
exercised. The notice shall be accompanied by payment in the form of cash or
check payable to the order of the Company in an amount equal to the exercise
price of the shares of Common Stock to be purchased or, if the Committee had so
authorized on the grant of an Incentive Option or on or after grant of a
Nonstatutory Option (and subject to such conditions, if any, as the Committee
may deem necessary to avoid adverse accounting effects to the Company) by
delivery to the Company of shares of Common Stock having a Market Value equal to
the exercise price of the shares to be purchased. Payment may also be made
through and under the terms and conditions of any formal cashless exercise
program authorized by the Company entailing the sale of Common Stock subject to
an Option in a brokered transaction (other than to the Company). Receipt by the
Company of such notice and payment in any authorized or combination of
authorized means shall constitute the exercise of the Option. Within thirty (30)
days thereafter but subject to the remaining provisions of the Plan, the Company
shall deliver or cause to be delivered to the Optionee or his agent a
certificate or certificates for the number of shares then being purchased. Such
shares shall be fully paid and nonassessable. Notwithstanding any of the
foregoing provisions in this subsection (g) to the contrary, (A) no Option shall
be considered to have been exercised unless and until all of the provisions
governing such exercise specified in the Plan and in the relevant Award
Agreement shall have been duly complied with; and (B) the obligation of the
Company to issue any shares upon exercise

<Page>

                                      - 8 -

of an Option is subject to the provisions of Section 9.1 hereof and to
compliance by the Optionee with all of the provisions of the Plan and the
relevant Award Agreement.

           (h)  LIMIT ON INCENTIVE OPTION CHARACTERIZATION. An Incentive Option
shall be considered to be an Incentive Option only to the extent that the number
of shares of Common Stock for which the Option first becomes exercisable in a
calendar year do not have an aggregate Market Value (as of the date of the grant
of the Option) in excess of the "current limit". The current limit for any
Optionee for any calendar year shall be $100,000 MINUS the aggregate Market
Value at the date of grant of the number of shares of Common Stock available for
purchase for the first time in the same year under each other Incentive Option
previously granted to the Optionee under the Plan, and under each other
incentive stock option previously granted to the Optionee under any other
incentive stock option plan of the Company and its Affiliates. Any shares of
Common Stock which would cause the foregoing limit to be violated shall be
deemed to have been granted under a separate Nonstatutory Option, otherwise
identical in its terms to those of the Incentive Option.

           (i)  NOTIFICATION OF DISPOSITION. Each person exercising any
Incentive Option granted under the Plan shall be deemed to have covenanted with
the Company to report to the Company any disposition of such shares prior to the
expiration of the holding periods specified by Section 422(a)(1) of the Code
and, if and to the extent that the realization of income in such a disposition
imposes upon the Company federal, state, local or other withholding tax
requirements, or any such withholding is required to secure for the Company an
otherwise available tax deduction, to remit to the Company an amount in cash
sufficient to satisfy those requirements.

           (j)  RIGHTS PENDING EXERCISE. No person holding an Option shall be
deemed for any purpose to be a stockholder of the Company with respect to any of
the shares of Common Stock issuable pursuant to his Option, except to the extent
that the Option shall have been exercised with respect thereto and, in addition,
a certificate shall have been issued therefor and delivered to such holder or
his agent.

     7.2.  RESTRICTED STOCK.

           (a)  PURCHASE PRICE. Shares of Restricted Stock shall be issued under
the Plan for such consideration, in cash, other property or services, or any
combination thereof, as is determined by the Committee.

           (b)  ISSUANCE OF CERTIFICATES. Subject to subsection (c) below, each
Participant receiving an Award of Restricted Stock shall be issued a stock
certificate in respect of such shares of Restricted Stock. Such certificate
shall be registered in the name of such Participant, and, if applicable, shall
bear an appropriate legend referring to the terms, conditions, and restrictions
applicable to such Award substantially in the following form:

     The transferability of this certificate and the shares represented by this
     certificate are subject to the terms and conditions of the TolerRx, Inc.

<Page>

                                      - 9 -

     Amended and Restated 2000 Equity Incentive Plan and an Award Agreement
     entered into by the registered owner and TolerRx, Inc. Copies of such Plan
     and Agreement are on file in the offices of TolerRx, Inc.

           (c)  ESCROW OF SHARES. The Committee may require that the stock
certificates evidencing shares of Restricted Stock be held in custody by a
designated escrow agent (which may but need not be the Company) until the
restrictions thereon shall have lapsed, and that the Participant deliver a stock
power, endorsed in blank, relating to the Common Stock covered by such Award.

           (d)  RESTRICTIONS AND RESTRICTION PERIOD. During the Restriction
Period applicable to shares of Restricted Stock, such shares shall be subject to
limitations on transferability and a Risk of Forfeiture arising on the basis of
such conditions related to the performance of services, Company or Affiliate
performance or otherwise as the Committee may determine and provide for in the
applicable Award Agreement. Any such Risk of Forfeiture may be waived or
terminated, or the Restriction Period shortened, at any time by the Committee on
such basis as it deems appropriate.

           (e)  RIGHTS PENDING LAPSE OF RISK OF FORFEITURE OR FORFEITURE OF
AWARD. Except as otherwise provided in the Plan or the applicable Award
Agreement, at all times prior to lapse of any Risk of Forfeiture applicable to,
or forfeiture of, an Award of Restricted Stock, the Participant shall have all
of the rights of a stockholder of the Company, including the right to vote the
shares of Restricted Stock.

           (f)  EFFECT OF TERMINATION OF EMPLOYMENT, CONSULTING OR BOARD MEMBER
RELATIONSHIP. Unless otherwise determined by the Committee at or after grant and
subject to the applicable provisions of the Award Agreement, if a Participant's
employment, consulting or Board member relationship with the Company and its
Affiliates ends for any reason during the Restriction Period, including because
an entity with which the Participant has an employment, consulting or Board
member relationship ceases to be an Affiliate of the Company, all shares of
Restricted Stock still subject to Risk of Forfeiture shall be forfeited or
otherwise subject to return to or repurchase by the Company on the terms
specified in the Award Agreement; PROVIDED, HOWEVER, that military or sick leave
or other bona fide leave shall not be deemed a termination of employment, if it
does not exceed the longer of ninety (90) days or the period during which the
absent Participant's reemployment rights, if any, are guaranteed by statute or
by contract.

           (g)  LAPSE OF RESTRICTIONS. If and when the Restriction Period
expires without a prior forfeiture of the Restricted Stock, the certificates for
such shares shall be delivered to the Participant promptly if not theretofore so
delivered.

     7.3.  STOCK GRANTS.

           (a)  IN GENERAL. Stock Grants shall be issued for such consideration,
in cash, other property or services, or any combination thereof, as is
determined by the Committee. Without limiting the generality of the foregoing,
Stock Grants may be

<Page>

                                     - 10 -

awarded in such circumstances as the Committee deems appropriate, including
without limitation in recognition of significant contributions to the success of
the Company or its Affiliates or in lieu of compensation otherwise already due.
Stock Grants shall be made without forfeiture conditions of any kind.

           (b)  ISSUANCE OF CERTIFICATES. Each Participant receiving a Stock
Grant shall be issued a stock certificate in respect of such Stock Grant. Such
certificate shall be registered in the name of such Participant, and, if
applicable, shall bear an appropriate legend referring to the terms, conditions,
and restrictions applicable to such Award substantially in the following form:

     The transferability of this certificate and the shares represented by this
     certificate are subject to the terms and conditions of the TolerRx, Inc.
     Amended and Restated 2000 Equity Incentive Plan. A copy of such Plan is on
     file in the offices of TolerRx, Inc.

     7.4.  AWARDS TO PARTICIPANTS OUTSIDE THE UNITED STATES. The Committee may
modify the terms of any Award under the Plan granted to a Participant who is, at
the time of grant or during the term of the Award, resident or primarily
employed outside of the United States in any manner deemed by the Committee to
be necessary or appropriate in order that such Award shall conform to laws,
regulations, and customs of the country in which the Participant is then
resident or primarily employed, or so that the value and other benefits of the
Award to the Participant, as affected by foreign tax laws and other restrictions
applicable as a result of the Participant's residence or employment abroad,
shall be comparable to the value of such an Award to a Participant who is
resident or primarily employed in the United States. An Award may be modified
under this Section 7.4 in a manner that is inconsistent with the express terms
of the Plan, so long as such modifications will not contravene any applicable
law or regulation.

     7.5.  AUTOMATIC GRANTS TO NON-MANAGEMENT DIRECTORS.

           (a)  Each non-management director shall be granted upon his
initial election to the board an Award covering 30,000 shares of Common
Stock, which Award shall be, at the election of each non-management director,
in the form of either (i) an Option which shall become exercisable,
cumulatively, in a series of three (3) successive, equal annual installments,
with the first installment to become exercisable on, or at any time after,
the first year anniversary of the Grant Date or (ii) Restricted Stock for
which the Risk of Forfeiture shall expire in a series of three (3)
successive, equal annual installments, with the first installment to expire
on, or at any time after, the first year anniversary of the grant date of the
Award.

           (b)  Each non-management director shall be granted automatically
each year on the anniversary of the first date of his or her term of service on
the Board an Award

<Page>

                                     - 11 -

covering 20,000 shares of Common Stock, which Award shall be, at the election
of each non-management director, in the form of either (i) an Option which
shall become fully exercisable on the first year anniversary of the Grant
Date or (ii) Restricted Stock for which the Risk of Forfeiture shall expire
on the first year anniversary of the grant date of the Award.

8.   ADJUSTMENT PROVISIONS

     8.1.  ADJUSTMENT FOR CORPORATE ACTIONS. All of the share numbers set forth
in the Plan reflect the capital structure of the Company as of
__________________, 2003. Subject to the provisions of Section 8.2, if
subsequent to such date the outstanding shares of Common Stock (or any other
securities covered by the Plan by reason of the prior application of this
Section) are increased, decreased, or exchanged for a different number or kind
of shares or other securities, or if additional shares or new or different
shares or other securities are distributed with respect to such shares of Common
Stock or other securities, through merger, consolidation, sale of all or
substantially all the property of the Company, reorganization, recapitalization,
reclassification, stock dividend, stock split, reverse stock split, or other
distribution with respect to such shares of Common Stock, or other securities,
an appropriate and proportionate adjustment will be made in (i) the maximum
numbers and kinds of shares provided in Section 4, (ii) the numbers and kinds of
shares or other securities subject to the then outstanding Awards, (iii) the
exercise price for each share or other unit of any other securities subject to
then outstanding Options (without change in the aggregate purchase price as to
which such Options remain exercisable), and (iv) the repurchase price of each
share of Restricted Stock then subject to a Risk of Forfeiture in the form of a
Company repurchase right.

        8.2.  CHANGE OF CONTROL. Subject to the applicable provisions of the
Award Agreement, in the event of a Change of Control, the Board of Directors
shall have the discretion, exercisable in advance of, at the time of, or
(except to the extent otherwise provided below) at any time after, such
Change of Control, to provide for any or all of the following (subject to and
upon such terms as the Board of Directors may deem appropriate): (A) the
Acceleration of any or all outstanding Options (including Options that are
assumed or replaced pursuant to clause (C) below) that are not exercisable in
full at the time the Change of Control, such Acceleration to become effective
at the time of the Change of Control, or at such time following the Change of
Control that the employment, consulting or Board member relationship of the
applicable Optionee or Optionees with the Company and its Affiliates
terminates, or at such other time or times as the Board of Directors shall
determine; (B) the termination of any or all of the Company's repurchase
rights with respect to Restricted Stock Awards, such termination to become
effective at the time of the Change of Control, or at such time following the
Change of Control that the employment, consulting or Board member
relationship with the Company and its Affiliates of the Participant or
Participants that hold such Restricted

<Page>

                                     - 12 -

Stock Awards terminates, or at such other time or times as the Board of
Directors shall determine; (C) the assumption of outstanding Options, or the
substitution of outstanding Options with equivalent options, by the acquiring
or succeeding corporation or entity (or an affiliate thereof); or (D) the
termination of all Options (other than Options that are assumed or
substituted pursuant to clause (C) above) that remain outstanding at the time
of the consummation of the Change of Control, PROVIDED THAT, the Board of
Directors shall have made the determination to effect such termination prior
to the consummation of the Change of Control and the Board of Directors shall
have given, or caused to be given, to all Optionees written notice of such
potential termination at least five (5) business days prior to the
consummation of the Change of Control. Notwithstanding the foregoing, subject
to the applicable provisions of the Award Agreement, in the event of the
closing of a Sale of the Company Transaction in which the acquiring or
succeeding corporation or entity does not have an equity incentive plan under
which all outstanding Options may be assumed or pursuant to which options may
be issued in substitution of all outstanding Options, the vesting of all
outstanding Options shall Accelerate by one year, such Acceleration to become
effective upon the closing of the Sale of the Company Transaction. The
provisions of this Section 8.2 shall not be construed as to limit or restrict
in any way the Committee's general authority under Sections 7.1(d) or 7.2(d)
hereof to Accelerate Options in whole or in part at any time or to waive or
terminate at any time any Risk of Forfeiture applicable to shares of
Restricted Stock. Each outstanding Option that is assumed in connection with
a Change of Control, or is otherwise to continue in effect subsequent to a
Change of Control, will be appropriately adjusted, immediately after the
Change of Control, as to the number and class of securities and the price at
which it may be exercised in accordance with Section 8.1.

     8.3.  DISSOLUTION OR LIQUIDATION.   Upon dissolution or liquidation of the
Company, each outstanding Option shall terminate, but the Optionee (if at the
time he or she has an employment, consulting or Board member relationship with
the Company or any of its Affiliates) shall have the right, immediately prior to
such dissolution or liquidation, to exercise the Option to the extent
exercisable on the date of such dissolution or liquidation.

     8.4.  RELATED MATTERS.   Any adjustment in Awards made pursuant to this
Section 8 shall be determined and made, if at all, by the Committee and shall
include any correlative modification of terms, including of Option exercise
prices, rates of vesting or exercisability, Risks of Forfeiture and applicable
repurchase prices for Restricted Stock, which the Committee may deem necessary
or appropriate so as to ensure that the rights of the Participants in their
respective Awards are not substantially diminished nor enlarged as a result of
the adjustment and corporate action other than as expressly contemplated in this
Section 8. No fraction of a share shall be purchasable or deliverable upon
exercise, but in the event any adjustment hereunder of the number of shares
covered by an Award shall cause such number to include a fraction of a share,
such number of shares shall be adjusted to the nearest smaller whole number of
shares. No adjustment of an Option exercise price per share pursuant to this
Section 8 shall result in an exercise price which is less than the par value of
the Common Stock.

<Page>

                                     - 13 -

9.   SETTLEMENT OF AWARDS

     9.1.  VIOLATION OF LAW. Notwithstanding any other provision of the Plan or
the relevant Award Agreement, if, at any time, in the reasonable opinion of the
Company, the issuance of shares of Common Stock covered by an Award may
constitute a violation of law, then the Company may delay such issuance and the
delivery of a certificate for such shares until (i) approval shall have been
obtained from such governmental agencies, other than the Securities and Exchange
Commission, as may be required under any applicable law, rule, or regulation and
(ii) in the case where such issuance would constitute a violation of a law
administered by or a regulation of the Securities and Exchange Commission, one
of the following conditions shall have been satisfied:

           (a)  the shares are at the time of the issue of such shares
effectively registered under the Securities Act; or

           (b)  the Company shall have determined, on such basis as it deems
appropriate (including an opinion of counsel in form and substance satisfactory
to the Company) that the sale, transfer, assignment, pledge, encumbrance or
other disposition of such shares or such beneficial interest, as the case may
be, does not require registration under the Securities Act or any applicable
state securities laws.

     9.2.  RESTRICTIONS ON RIGHTS IN STOCK. Any Common Stock to be issued
pursuant to Awards granted under the Plan shall be subject to such stop-transfer
orders and other restrictions as the Committee may deem advisable under the
rules, regulations, and other requirements of any stock exchange upon which the
Common Stock is then listed, and any applicable federal or state securities law,
and the Committee may cause a legend or legends to be put on any such
certificates to make appropriate reference to such restrictions.

     9.3.  INVESTMENT REPRESENTATIONS. The Company shall be under no obligation
to issue any shares covered by an Award unless the shares to be issued pursuant
to Awards granted under the Plan have been effectively registered under the
Securities Act or the Participant shall have made such written representations
to the Company (upon which the Company believes it may reasonably rely) as the
Company may deem necessary or appropriate for purposes of confirming that the
issuance of such shares will be exempt from the registration requirements of
that Act and any applicable state securities laws and otherwise in compliance
with all applicable laws, rules and regulations, including but not limited to
that the Participant is acquiring shares for his or her own account for the
purpose of investment and not with a view to, or for sale in connection with,
the distribution of any such shares.

     9.4.  REGISTRATION. If the Company shall deem it necessary or desirable to
register under the Securities Act or other applicable statutes any shares of
Common Stock issued or to be issued pursuant to Awards granted under the Plan,
or to qualify any such shares of Common Stock for exemption from the Securities
Act or other applicable statutes, then the Company shall take such action at its
own expense. The Company may

<Page>

                                     - 14 -

require from each recipient of an Award, or each holder of shares of Common
Stock acquired pursuant to the Plan, such information in writing for use in any
registration statement, prospectus, preliminary prospectus or offering circular
as is reasonably necessary for such purpose and may require reasonable indemnity
to the Company and its officers and directors from such holder against all
losses, claims, damage and liabilities arising from such use of the information
so furnished and caused by any untrue statement of any material fact therein or
caused by the omission to state a material fact required to be stated therein or
necessary to make the statements therein not misleading in the light of the
circumstances under which they were made.

     9.5.  LOCK-UP. Without the prior written consent of the Company or the
managing underwriter in any public offering of shares of Common Stock, no
Participant shall sell, make any short sale of, loan, grant any option for the
purchase of, pledge or otherwise encumber, or otherwise dispose of, any shares
of Common Stock during the one hundred-eighty (180) day period commencing on the
effective date of the registration statement relating to any underwritten public
offering of securities of the Company. The foregoing restrictions are intended
and shall be construed so as to preclude any Participant from engaging in any
hedging or other transaction that is designed to or reasonably could be expected
to lead to or result in, a sale or disposition of any shares of Common Stock
during such period even if such shares of Common Stock are or would be disposed
of by someone other than such Participant. Such prohibited hedging or other
transactions would include, without limitation, any short sale (whether or not
against the box) or any purchase, sale or grant of any right (including without
limitation any put or call option) with respect to any shares of Common Stock or
with respect to any security that includes, relates to, or derives any
significant part of its value from any shares of Common Stock. Without limiting
the generality of the foregoing provisions of this Section 9.5, if, in
connection with any underwritten public offering of securities of the Company,
the managing underwriter of such offering requires that the Company's directors
and officers enter into a lock-up agreement containing provisions that are more
restrictive than the provisions set forth in the preceding sentence, then (a)
each Participant (regardless of whether or not such Participant has complied or
complies with the provisions of clause (b) below) shall be bound by, and shall
be deemed to have agreed to, the same lock-up terms as those to which the
Company's directors and officers are required to adhere; and (b) at the request
of the Company or such managing underwriter, each Participant shall execute and
deliver a lock-up agreement in form and substance equivalent to that which is
required to be executed by the Company's directors and officers.

     9.6.  PLACEMENT OF LEGENDS; STOP ORDERS; ETC. Each share of Common Stock to
be issued pursuant to Awards granted under the Plan may bear a reference to the
investment representations made in accordance with Section 9.3 in addition to
any other applicable restrictions under the Plan, the terms of the Award and to
the fact that no registration statement has been filed with the Securities and
Exchange Commission in respect to such shares of Common Stock. All certificates
for shares of Common Stock or other securities delivered under the Plan shall be
subject to such stock transfer orders and other restrictions as the Committee
may deem advisable under the rules, regulations, and

<Page>

                                     - 15 -

other requirements of any stock exchange upon which the Common Stock is then
listed, and any applicable federal or state securities law, and the Committee
may cause a legend or legends to be placed on any such certificates to make
appropriate reference to such restrictions.

     9.7.  TAX WITHHOLDING. Whenever shares of Common Stock are issued or to be
issued pursuant to Awards granted under the Plan, the Company shall have the
right to require the recipient to remit to the Company an amount sufficient to
satisfy federal, state, local or other withholding tax requirements if, when,
and to the extent required by law (whether so required to secure for the Company
an otherwise available tax deduction or otherwise) prior to the delivery of any
certificate or certificates for such shares. The obligations of the Company
under the Plan shall be conditional on satisfaction of all such withholding
obligations and the Company shall, to the extent permitted by law, have the
right to deduct any such taxes from any payment of any kind otherwise due to the
recipient of an Award.

10.  RESERVATION OF STOCK

     The Company shall at all times during the term of the Plan and any
outstanding Options granted hereunder reserve or otherwise keep available such
number of shares of Common Stock as will be sufficient to satisfy the
requirements of the Plan (if then in effect) and such Options and shall pay all
fees and expenses necessarily incurred by the Company in connection therewith.

11.  NO SPECIAL SERVICE RIGHTS

     Nothing contained in the Plan or in any Award Agreement shall confer upon
any recipient of an Award any right with respect to the continuation of his or
her employment, consulting or Board member relationship with the Company (or any
Affiliate), or interfere in any way with the right of the Company (or any
Affiliate), subject to the terms of any separate employment, consulting or Board
member agreement or provision of law or corporate articles or by-laws to the
contrary, at any time to terminate such employment, consulting or Board member
agreement or to increase or decrease, or otherwise adjust, the other terms and
conditions of the recipient's employment, consulting or Board member
relationship with the Company and its Affiliates.

12.  NONEXCLUSIVITY OF THE PLAN

     Neither the adoption of the Plan by the Board nor the submission of the
Plan to the stockholders of the Company shall be construed as creating any
limitations on the power of the Board to adopt such other incentive arrangements
as it may deem desirable, including without limitation, the granting of stock
options and restricted stock other than under the Plan, and such arrangements
may be either applicable generally or only in specific cases.

<Page>

                                     - 16 -

13.  TERMINATION AND AMENDMENT OF THE PLAN

     The Board may at any time terminate the Plan or make such amendments or
modifications of the Plan as it shall deem advisable. In the event of the
termination of the Plan, the terms of the Plan shall survive any such
termination with respect to any Award that is outstanding on the date of such
termination, unless the holder of such Award agrees in writing to terminate such
Award or to terminate all or any of the provisions of the Plan that apply to
such Award. Unless the Board otherwise expressly provides, any amendment or
modification of the Plan shall affect the terms of any Award outstanding on the
date of such amendment or modification as well as the terms of any Award made
from and after the date of such amendment or modification; PROVIDED, HOWEVER,
that, except to the extent otherwise provided in the last sentence of this
paragraph, (i) no amendment or modification of the Plan shall apply to any Award
that is outstanding on the date of such amendment or modification if such
amendment or modification would reduce the number of shares subject to such
Award, increase the purchase price applicable to shares subject to such Award or
materially adversely affect the provisions applicable to such Award that relate
to the vesting or exercisability of such Award or of the shares subject to such
Award, (ii) no amendment or modification of the Plan shall apply to any
Incentive Option that is outstanding on the date of such amendment or
modification if such amendment or modification would result in such Incentive
Option no longer being treated as an "incentive stock option" within the meaning
of Section 422 of the Code and (iii) no amendment or modification of the Plan
shall apply to any Award that is outstanding on the date of such amendment or
modification unless such amendment or modification of the Plan shall also apply
to all other Awards outstanding on the date of such amendment or modification.
In the event of any amendment or modification of the Plan that is described in
clause (i), (ii) or (iii) of the foregoing proviso, such amendment or
modification of the Plan shall apply to any Award outstanding on the date of
such amendment or modification only if the recipient of such Award consents in
writing thereto.

     The Committee may amend or modify, prospectively or retroactively, the
terms of any Award theretofore granted without amending or modifying the terms
of the Plan itself, PROVIDED that as amended or modified such Award is
consistent with the terms of the Plan as in effect at the time of the amendment
or modification of such Award, but no such amendment or modification of such
Award shall, without the written consent of the recipient of such Award, reduce
the number of shares subject to such Award, increase the purchase price
applicable to shares subject to such Award, adversely affect the provisions
applicable to such Award that relate to the vesting or exercisability of such
Award or of the shares subject to such Award, otherwise materially adversely
affect the terms of such Award (except for amendments or modifications to the
terms of such Award or of the stock subject to such Award that are expressly
permitted by the terms of the Plan or that result from any amendment or
modification of the Plan in accordance with the provisions of the first
paragraph of this Section 13), or, if such Award is an Incentive Option, result
in such Incentive Option no longer being treated as an "incentive stock option"
within the meaning of Section 422 of the Code.

<Page>

                                     - 17 -

14.  INTERPRETATION OF THE PLAN

     In the event of any conflict between the provisions of this Plan and the
provisions of any applicable Award Agreement, the provisions of such Award
Agreement shall control, but insofar as possible the provisions of the Plan and
such Award Agreement shall be construed so as to give full force and effect to
all such provisions.

15.  NOTICES AND OTHER COMMUNICATIONS

     Any notice, demand, request or other communication hereunder to any party
shall be deemed to be sufficient if contained in a written instrument delivered
in person or duly sent by first class registered, certified or overnight mail,
postage prepaid, or telecopied with a confirmation copy by regular, certified or
overnight mail, addressed or telecopied, as the case may be, (i) if to the
recipient of an Award, at his or her residence address last filed with the
Company and (ii) if to the Company, at its principal place of business,
addressed to the attention of its Chief Executive Officer, or to such other
address or telecopier number, as the case may be, as the addressee may have
designated by notice to the addressor. All such notices, requests, demands and
other communications shall be deemed to have been received: (i) in the case of
personal delivery, on the date of such delivery; (ii) in the case of mailing,
when received by the addressee; and (iii) in the case of facsimile transmission,
when confirmed by facsimile machine report.

16.  GOVERNING LAW

     The Plan and all Award Agreements and actions taken thereunder shall be
governed, interpreted and enforced in accordance with the laws of the
Commonwealth of Massachusetts, without regard to the conflict of laws principles
thereof.

<Page>
                                  TOLERRX, INC.

                       NONSTATUTORY STOCK OPTION AGREEMENT

         NONSTATUTORY STOCK OPTION AGREEMENT, dated as of _______________ (this
"Agreement"), between TolerRx, Inc., a Delaware corporation (the "Company"), and
___________________ (the "Optionee").

         1. GRANT OF OPTION.

         Pursuant to the Company's Amended and Restated 2000 Equity Incentive
Plan, as amended from time to time (the "Plan"), a copy of which is attached
hereto as Exhibit A, the Company grants to the Optionee an option (the "Option")
to purchase from the Company all or any part of a total of _____________ shares
(the "Optioned Shares") of the Company's common stock, $.001 par value, at a
price of $____________ per share. The Option is granted as of _________________
(the "Grant Date").

         2. CHARACTER OF OPTION.

         The Option is not intended to be treated as an "incentive stock option"
within the meaning of Section 422 of the Internal Revenue Code of 1986, as
amended (the "Code"), but as a nonstatutory stock option within the meaning of
the Code.

         3. DURATION OF OPTION.

         Unless subject to earlier expiration pursuant to the terms of the Plan,
the Option shall expire on ___________.

         4. EXERCISE OF OPTION.

         Until its  expiration  pursuant to Section 3 hereof,  the Option may be
exercised  in the manner  specified  in Section  7.1(f) of the Plan as  follows:
[INSERT VESTING SCHEDULE].

         5. TRANSFER OF OPTIONS.

         The Option may not be transferred except by prior written consent of
the Company.

         6. INCORPORATION OF PLAN TERMS.

         The Option is granted subject to all of the applicable terms and
provisions of the Plan, including but not limited to the limitations on the
Company's obligation to deliver the Optioned Shares upon exercise thereof as set
forth in Section 9 of the Plan.
<Page>
         7. MISCELLANEOUS.

         This Agreement shall be construed and enforced in accordance with the
laws of the Commonwealth of Massachusetts and shall be binding upon and inure to
the benefit of any successor or assign of the Company and any assign, executor,
administrator, trustee, guardian, or other legal representative of the Optionee.

         IN WITNESS WHEREOF, the parties have executed this Agreement as a
sealed instrument as of the date first above written.

TOLERRX, INC.                                 OPTIONEE

By:
     --------------------------------         --------------------------------
        Douglas J. Ringler                       [Insert Name of Optionee]
        President

                                              Address:

                                              --------------------------------

                                              --------------------------------

                                              --------------------------------
<Page>
                                  TOLERRX, INC.

                        INCENTIVE STOCK OPTION AGREEMENT

         INCENTIVE STOCK OPTION AGREEMENT, dated as of ___________ (this
"Agreement"), between TolerRx, Inc., a Delaware corporation (the "Company"), and
_________________ (the "Optionee").

         1. GRANT OF OPTION.

         Pursuant to the Company's Amended and Restated 2000 Equity Incentive
Plan, as amended from time to time (the "Plan"), a copy of which is attached
hereto as Exhibit A, the Company grants to the Optionee an option (the "Option")
to purchase from the Company all or any part of a total of _________________
shares (the "Optioned Shares") of the Company's common stock, $.001 par value,
at a price of $_____________ per share. The Option is granted as of
_______________ (the "Grant Date").

         2. CHARACTER OF OPTION.

         The Option is intended to be treated as an "incentive stock option"
within the meaning of Section 422 of the Internal Revenue Code of 1986, as
amended.

         3. DURATION OF OPTION.

         Unless subject to earlier expiration pursuant to the terms of the Plan,
the Option shall expire on the earlier of (i) the tenth anniversary of the Grant
Date or (ii) the 90th day following the termination of the Optionee's employment
with the Company for any reason.

         4. EXERCISE OF OPTION.

         Until its expiration pursuant to Section 3 hereof, the Option may be
exercised in the manner specified in Section 7.1(f) of the Plan as follows:
[INSERT VESTING SCHEDULE (e.g., (i) ____________ percent (___%) of the Optioned
Shares shall vest on and after _________ __, 200_, and (ii) the remaining
_______________ percent (___%) of the Optioned Shares shall vest in a series of
____________ (___) equal installments, in portions of whole shares as nearly
equal as practicable, with each installment vesting on _____________, until all
of the Optioned Shares are fully vested.]

         5. Transfer of Options.

         The Option may not be transferred except by will or the laws of descent
and distribution, and, during the lifetime of the Optionee, may be exercised
only by the Optionee.
<Page>
         6. INCORPORATION OF PLAN TERMS.

         The Option is granted subject to all of the applicable terms and
provisions of the Plan, including but not limited to the limitations on the
Company's obligation to deliver Optioned Shares upon exercise thereof as set
forth in Section 9 of the Plan.

         7. MISCELLANEOUS.

         This Agreement shall be construed and enforced in accordance with the
laws of the Commonwealth of Massachusetts and shall be binding upon and inure to
the benefit of any successor or assign of the Company and any executor,
administrator, trustee, guardian, or other legal representative of the Optionee.

         IN WITNESS WHEREOF, the parties have executed this Agreement as a
sealed instrument as of the date first above written.

TOLERRX, INC.                                 OPTIONEE

By:  --------------------------------         --------------------------------
        Douglas J. Ringler                       [Insert Name of Optionee]
        President

                                              Address:

                                              --------------------------------

                                              --------------------------------

                                              --------------------------------

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00057-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00057-of-00352.parquet"}]]