Exhibit 10.1


                                 LOAN AGREEMENT

      This Loan Agreement,  dated as of November 12, 2007, (this "Agreement") is
entered into by and between Raven biotechnologies,  inc., a Delaware corporation
(the "Company"), and VaxGen, Inc., a Delaware corporation (the "Lender").

                                    RECITALS

      A. The  Company  and Lender are in the  process  of  negotiating  a merger
transaction pursuant to which the Company would become a wholly-owned subsidiary
of Lender  (the  "Merger  Transaction"),  pursuant to an  Agreement  and Plan of
Merger dated as of November 12, 2007 (the "Merger Agreement").

      B. On the terms and subject to the conditions set forth herein,  Lender is
willing to  purchase  from the  Company,  and the  Company is willing to sell to
Lender the promissory note described below.

      D. Capitalized  terms not otherwise  defined herein shall have the meaning
set forth in the form of Note (as defined below) attached hereto as Exhibit A.

                                    AGREEMENT

      NOW THEREFORE, in consideration of the foregoing, and the representations,
warranties,  and conditions set forth below, the parties hereto, intending to be
legally bound, hereby agree as follows:


      1. The Loan.

         (a)  Issuance of Note.  The Lender has agreed to lend to the Company up
to Six Million Dollars ($6,000,000.00) in principal (the "Total Loan Amount") in
return  for a  secured  promissory  note in the form of  Exhibit  A hereto  (the
"Note") and a Security  Agreement in the form of Exhibit B hereto (the "Security
Agreement").  As more fully set forth in Section 4(e) below,  the Lender and the
Company have agreed that the Lender may pay off and  discharge  the VLL Loan (as
defined below).  The Total Loan Amount shall be increased by the amount, if any,
the Lender pays to VLL (as defined below).


         (b) Advances.  Subject to and upon the terms and  conditions  set forth
below,  the  Company may  request  advances  of funds  under the Note (each,  an
"Advance")  in  accordance  with  Schedule 1 attached  hereto (the  "Schedule of
Advances")  in an  aggregate  outstanding  amount  not to exceed  the Total Loan
Amount,  commencing on December 1, 2007. As further  described on Schedule 1 and
in  accordance  with the terms of Schedule  1, a portion of each  Advance may be
made in the form of services provided to Company by Lender.  Each Advance to the
Company  under the Note shall be subject to the  satisfaction  of the  following
conditions  precedent (unless waived in writing by the Lender):  (i) each of the
representations  and  warranties  contained in this

                                       1
<PAGE>

Agreement and the Security  Agreement  must be true and accurate in all material
respects  as of the  date of such  advance,  and  (ii)  the  Company  must  have
performed all of its obligations under this Agreement, the Merger Agreement, the
Note and the Security  Agreement.  The Lender's  obligation to make any Advances
shall  terminate upon the earliest of: (1)  consummation of Merger I (as defined
in the Merger Agreement), (2) April 1, 2008, provided that, if Lender reasonably
determines in good faith that the Merger Agreement will not be consummated on or
before April 15, 2008, due to the SEC requiring  either Lender or the Company to
file audited fiscal year financial  statements for the period ended December 31,
2007, and which financial statements are not reasonably expected to be completed
prior to April 15, 2008, then the Lender's  obligation to make further  Advances
shall terminate March 31, 2008, (3) 30 days following  termination of the Merger
Agreement  for any reason other than a breach by the Company of its  obligations
under the Merger  Agreement  or the  Company's  determination  to pursue a Razor
Alternative Transaction (as defined in the Merger Agreement), or (4) the date of
termination  of the  Merger  Agreement  by the  Lender  due to the breach by the
Company of its  obligations  under the Merger  Agreement,  or as a result of the
Lender's determination to pursue a Panther Alternative  Transaction in which the
Lender pays the breakup fee as set forth in the Merger Agreement.

         (c) Use of Proceeds.  The proceeds of each Advance shall be used solely
for  operating  expenses of the  Company as set forth on Schedule 2 hereto,  and
shall  not be used  for any  fees,  expenses  or  costs  of the  Company  or any
affiliate of the Company  relating to the Merger  Transaction or with respect to
any  compensation,  retention and/or severance  obligations of the Company.  The
Company hereby authorizes the Lender and its designated  representatives  during
normal  business hours and upon  reasonable  notice,  to conduct a review of the
Company's books and records sufficient to reasonably satisfy the Lender that the
proceeds of the  Advances  were used as set forth in the first  sentence of this
Section 1(c).

         (d)  Payments of  Advances.  The Lender  will make all  advances to the
Company in immediately  available  funds by 11:00 a.m.  Pacific time on the date
such  advancement  is due  pursuant  to Schedule 1 hereto to the account for the
benefit of the Company as set forth on Schedule 1 hereto

      2.  Representations and Warranties of the Company.  Except as set forth on
Schedule 3 hereto, the Company represents and warrants to the Lender that:

         (a)  Due  Incorporation,  Qualification,  etc.  The  Company  (i)  is a
corporation validly existing and in good standing under the laws of the state of
Delaware;  (ii) has the power to carry on its  business  as now  conducted;  and
(iii) is duly  qualified,  licensed  to do  business  and in good  standing as a
foreign corporation in each jurisdiction where the failure to be so qualified or
licensed could  reasonably be expected to have a material  adverse effect on the
Company's  business,  properties,  assets,  liabilities,   prospects,  financial
condition, operations or otherwise (a "Material Adverse Effect").

         (b) Authority.  The execution,  delivery and performance by the Company
of each  Transaction  Document (as defined in Section 5 below) to be executed by
the Company and the  consummation of the transactions  contemplated  thereby (i)
are within the power of the  Company and (ii) have been duly  authorized  by all
necessary actions on the part of the Company.

                                       2
<PAGE>

         (c)  Enforceability.  Each  Transaction  Document  executed,  or  to be
executed,  by the Company has been,  or will be, duly  executed and delivered by
the Company and  constitutes,  or will  constitute,  a legal,  valid and binding
obligation of the Company,  enforceable  against the Company in accordance  with
its terms, except as limited by bankruptcy,  insolvency or other laws of general
application  relating to or  affecting  the  enforcement  of  creditors'  rights
generally and general principles of equity.

         (d) Non-Contravention. The execution and delivery by the Company of the
Transaction   Documents   executed  by  the  Company  and  the  performance  and
consummation of the  transactions  contemplated  thereby do not and will not (i)
violate  the  Certificate  or  Bylaws  ("Charter  Documents")  or  any  material
judgment,  order, writ, decree,  statute,  rule or regulation  applicable to the
Company;  (ii)  violate  any  provision  of,  or  result  in the  breach  or the
acceleration  of, or entitle any other person or entity to  accelerate  (whether
after the  giving of notice or lapse of time or both),  any  material  mortgage,
indenture,  agreement, instrument or contract to which the Company is a party or
by which it is bound;  or (iii) result in the creation or imposition of any Lien
upon  any  property,  asset  or  revenue  of  the  Company  or  the  suspension,
revocation,  impairment,  forfeiture,  or  nonrenewal  of any  material  permit,
license,  authorization or approval  applicable to the Company,  its business or
operations, or any of its assets or properties.

         (e)  Approvals  and Filings.  Except for  applicable  federal and state
securities  filings,  no  consent,  approval,  order  or  authorization  of,  or
registration,  declaration or filing with, any  governmental  authority or other
Person (including, without limitation, the shareholders of any person or entity)
is required in connection  with the  execution  and delivery of the  Transaction
Documents  executed by the Company and the performance  and  consummation of the
transactions contemplated thereby.

         (f) Valid  Issuance.  The Note,  when  issued,  sold and  delivered  in
compliance  with the  provisions  of this  Agreement,  will be duly and  validly
issued and will be free of any liens or encumbrances;  provided,  however,  that
the Note may be subject to  restrictions  on transfer under state and/or federal
securities laws and under the Transaction Documents.

         (g) No Violation  or Default.  The Company is not in violation of or in
default  with respect to (i) its Charter  Documents  or any  material  judgment,
order, writ, decree,  statute,  rule or regulation applicable to the Company; or
(ii) any material  mortgage,  indenture,  agreement,  instrument  or contract to
which such Person is a party or by which it is bound (nor is there any waiver in
effect  which,  if not in effect,  would result in such a violation or default),
where, in each case, such violation or default,  individually,  or together with
all such violations or defaults, would reasonably be expected to have a Material
Adverse Effect.

         (h) Litigation.  There is no action, suit,  proceeding or investigation
pending or, to the Company's  knowledge,  currently threatened before any court,
administrative  agency,  or  other  governmental  body  (nor,  to the  Company's
knowledge,  is  there  any  basis  for any  such  action,  suit,  proceeding  or
investigation) that might result,  either  individually or in the aggregate,  in
any Material Adverse Effect.  The Company is not a party or subject to, and none
of its  assets is bound by,  the  provisions  of any  order,  writ,  injunction,
judgment or decree of any court or government agency or  instrumentality.  There
is no action,  suit or proceeding by the Company  currently  pending or that the
Company intends to initiate.

                                       3
<PAGE>

         (i) Title to Property and Assets.  The Company has good and  marketable
title to all of its properties, intangible and tangible assets that it owns free
and clear of all mortgages, liens, loans, claims and encumbrances,  except liens
for current taxes and assessments  not yet due and minor liens and  encumbrances
which arise in the ordinary course of business and which do not, in any case, in
the aggregate,  materially detract from the value or use of the property subject
thereto or materially impair the operations of the Company.  With respect to the
property and assets it leases, the Company is in compliance with such leases and
holds a valid leasehold interest free of all liens, claims or encumbrances.

      3.  Representations  and  Warranties  of The  Lender.  The  Lender  hereby
represents and warrants to the Company as follows:

         (a) Binding Obligation.  The Lender has full legal capacity,  power and
authority to execute and deliver this  Agreement and to perform its  obligations
hereunder.  Each of this  Agreement and the Note issued to the Lender is a valid
and binding obligation of the Lender,  enforceable in accordance with its terms,
except as limited by bankruptcy, insolvency or other laws of general application
relating to or affecting  the  enforcement  of creditors'  rights  generally and
general principles of equity.

         (b)  Securities  Law  Compliance.  The Lender has been advised that the
Note has not been  registered  under the Securities Act of 1933, as amended (the
"Securities Act") or any state securities laws and, therefore,  cannot be resold
unless it is registered under the Securities Act and applicable state securities
laws or unless an exemption from such  registration  requirements  is available.
The Lender is an  "accredited  investor"  as such term is defined in Rule 501 of
Regulation D under the Securities Act.

      4. Covenants of the Company.

         (a) No New  Indebtedness.  Prior to the  earliest  of: (i) the Maturity
Date (as set forth in the Note) or (ii) the  payment in full of all  obligations
pursuant to the Note,  the  Company  shall not without the consent of the Lender
create,  incur,  assume or suffer to exist new  indebtedness  which is senior in
priority of payment to the Note; provided,  however,  that such limitation shall
not  apply to  unsecured  trade  debt  incurred  in the  ordinary  course of the
Company's business.

         (b) Monthly and Quarterly  Financials.  The Company shall  forward,  or
cause to be forwarded to the Lender by electronic mail,  followed  promptly by a
version in writing,  (a) the Company's monthly financial  statements prepared in
accordance  with  GAAP  (subject  to  normal  year-end  adjustments)  as soon as
available,  and in any event within twenty-eight (28) days after the end of each
month; and (b) the Company's quarterly consolidated and consolidating  financial
statements  prepared in  accordance  with GAAP  (including  a quarterly  balance
sheet,  profit and loss  statement and cash flow  statement for such quarter) as
soon as available,  and in any event within forty-five (45) days from the end of
each quarter.

         (c) Payments and Obligations to the Lender.  The Company shall make all
payments  of  principal,  interest  and other  charges as and when due under the
Note,  shall  perform  or  comply  with,  as the case may be,  all of the  other
obligation  under the Note and the  Security

                                       4
<PAGE>

Agreement,  and shall  perform and comply in all  respects  with all  applicable
terms,  conditions  and covenants of this  Agreement,  the Note and the Security
Agreement.

         (d) Other Debts; Taxes. The Company shall promptly make all payments of
principal  and  interest  as and when due under any  other  indebtedness  of the
Company and shall make payment of all other payment  obligations  of the Company
in excess of  $10,000  individually  within  fifteen  (15) days of such  payment
obligations  coming due and shall make payment of all other payment  obligations
of the Company within 30 days of such payments  coming due;  provided,  however,
that  this  covenant  shall  not be  construed  as  permitting  any  other  debt
obligations  of the  Company  or as  permitting  the making of any  payments  on
account of any other debt  obligations  of the  Company  that are not  otherwise
permitted by the terms and  conditions of this  Agreement.  The Company will pay
and discharge all material taxes, assessments and governmental charges or levies
imposed  upon them or upon  their  income  or  profits,  or upon any  properties
belonging to them, prior to the date on which material penalties attach thereto,
and all lawful claims which, if unpaid, might reasonably be expected to become a
lien or  charge  upon  any  properties  of the  Company  or cause a  failure  or
forfeiture of title thereto;  provided,  however,  that the Company shall not be
required to pay any such tax,  assessment,  charge,  levy or claim that is being
contested  in  good  faith  and by  proper  proceedings  timely  instituted  and
diligently  conducted if they have  maintained  adequate  reserves  with respect
thereto in accordance with GAAP.

         (e) Matters  Concerning  VLL  Indebtedness.  Prior to any Advance being
made,  the Company  shall obtain the  agreement  of Venture  Lending and Leasing
("VLL") in form and substance  satisfactory to the Lender  permitting the Lender
to cure any  monetary  default by the  Company  with  respect  to the  Company's
indebtedness  and other  obligations to VLL under that certain Loan and Security
Agreement,  dated as of  October  14,  2004,  as  amended  (the "VLL  Loan") and
permitting the Lender to pay off and discharge the VLL Loan at any time the Note
is  outstanding,  and that  upon  such pay off,  all  obligations  to VLL by the
Company under the VLL Loan shall be satisfied and discharged; provided, however,
that this requirement shall not, however,  be deemed to or construed as imposing
any duty upon the  Lender to cure any such  defaults  or any rights of any third
parties with respect to any such defaults, or to make any payment to pay off and
discharge the VLL Loan. Any funds made available by the Lender to the Company to
permit  the  Company  to cure  any  monetary  default  under,  or to pay off and
discharge,  the VLL Loan shall immediately and automatically become indebtedness
under the Note and the Total Loan Amount shall  automatically  be increased such
amount without any further act or notice by either the Company or the Lender.

         (f)  Protection  of  Collateral.  The Lender  shall take or cause to be
taken all steps and  perform or cause to be  performed  all  actions  reasonably
necessary or  appropriate  to  administer,  supervise,  preserve and protect the
Collateral (as defined in the Security Agreement),  and to maintain the Lenders'
perfected  security  interest in the Collateral  once such security  interest is
perfected.  If the Company  files with the United  States  Patent and  Trademark
Office  any   applications  or  other   documents   relating  to  the  Company's
Intellectual  Property (as defined in the Security Agreement),  then the Company
shall, no later than ten (10) days  thereafter,  notify the Lender in writing of
any such action,  and, at any time following the  effectiveness  of the security
interest,  upon the request of the Lender,  the Company  shall  execute and file
such collateral  assignments and related  documents in favor of the Lender,  and
otherwise cooperate with the Lender, to provide the Lender a valid and perfected
priority security interest in and to all of Seller's Intellectual Property.

                                       5
<PAGE>

         (g) Insurance. The Company shall maintain, in full force and effect its
existing  insurance  policies,  with a lender loss payee  clause in favor of the
Lender.

         (h) No  Distributions.  Unless otherwise agreed in writing by Lender in
advance or in connection with severance or retention payments in connection with
the Merger  Transaction,  the Company shall not make any  distributions of cash,
securities or other property of the Company to any of its equityholders, whether
such distribution would be characterized as a dividend or otherwise.

         (i) No Encumbrances.  The Company shall not permit to exist against any
of the  Collateral  or any of its  other  material  assets  (if any)  any  lien,
mortgage,   pledge,   security  interest,   title  retention  device,  or  other
encumbrance (collectively, "Liens"), except for those (i) Liens arising pursuant
to this Agreement, the Note and the Security Agreement;  (ii) Liens in existence
as of the date hereof under the VLL Loan;  (iii) Liens  incurred with respect to
the Note Purchase  Agreement  which are junior in terms of priority to the Liens
in favor of the Lender;  (iv) Liens for taxes and  assessments not delinquent or
actively being  contested in good faith by the Company and for which the Company
has adequate reserves; (v) deposits or pledges for goods or services made in the
ordinary course of the Company's  business;  (vi) mechanics  liens;  (vii) liens
that are junior in right of payment and collection and expressly subordinated to
the Liens  arising  pursuant to this  Agreement  and the Security  Agreement and
(viii)  statutory  liens  affecting  real  property of  landlords of the Company
Seller  (collectively such Liens permitted by clauses (i) through (viii) hereof,
"Permitted Liens").

         (j) No Payments of Junior Debt. The Company shall not make any payments
with respect to the  indebtedness  created or incurred  under the Note  Purchase
Agreement  unless all obligations then owing to the Lender under this Agreement,
the Note and the Security  Agreement  shall have been first paid and  discharged
and the Note shall have been terminated and discharged in full.

         (k) No Sale, License or Other Disposal of Assets. The Company shall not
in  any  manner  sell,  convey,  lease,  license,  transfer  or  dispose  of any
equitable,  beneficial or legal  interest in any of the Collateral or any of the
Company's  other material assets (if any),  except for equipment  disposed of in
the ordinary  course of business for at least the estimated fair market value of
such equipment as determined in good faith by the Company's board of directors

         (l) No Transactions  Outside the Ordinary Course. The Company shall not
enter into any agreements, obligations or commitments of any type, except in the
ordinary  course of  business  consistent  with past  practice  and  except  for
agreements,  contracts or commitments which involve payment by the Company which
individually  do not  exceed  $10,000,  and  which  collectively  do not  exceed
$50,000.

         (m) Compensation  Matters.  The Company shall not increase or commit to
increase  the  compensation  payable  or to become  payable to its  officers  or
employees  except  for  increases  in  salary or wages in  accordance  with past
practices or  agreements  listed on Schedule (m)

                                       6
<PAGE>

and in effect as of the date of this Agreement, in amounts not to exceed for any
individual  20% of the current salary or hourly wage of such  individual,  which
are first discussed with the Lender.

      5.  Certain  Default  Agreements.  In  addition  to each of the  Events of
Default  set  forth in the Note,  if the  Company  shall  commit a breach of the
Merger  Agreement such that the Merger Agreement may be terminated by the Lender
pursuant to Section  7.1(e) of the Merger  Agreement,  whether or not the Merger
Agreement  is in fact so  terminated,  then the Note  shall  be in  default  and
subject  to  acceleration  and  all  other  remedies  available  to the  Lender;
provided,  however,  the Lender agrees that until the Merger Agreement is either
terminated or consummated by its terms,  the Lender shall forbear from its right
to require  the  payment of all  outstanding  indebtedness  under the Note for a
period of 60 days from the date of termination of the Merger Agreement.  For the
avoidance of doubt, if the Merger is consummated no repayment shall be due under
the Note.

      6. Miscellaneous.

         (a) Waivers and  Amendments.  Any  provision of this  Agreement  may be
amended, waived or modified only upon the written consent of the Company and the
Lender.

         (b) Governing Law. This Agreement and all actions  arising out of or in
connection  with this Agreement shall be governed by and construed in accordance
with the laws of the State of Delaware,  without  regard to the conflicts of law
provisions of the State of Delaware or of any other state.

         (c) Survival. The representations, warranties, covenants and agreements
made herein shall survive the execution and delivery of this Agreement.

         (d) Successors  and Assigns.  Subject to the  restrictions  on transfer
described in Sections  6(e) and 6(f) below,  the rights and  obligations  of the
Company  and the  Lender  shall be  binding  upon and  benefit  the  successors,
assigns, heirs, administrators and transferees of the parties.

         (e) Assignment by the Company. Other than as contemplated in connection
with the Merger 2 (as defined in the Merger Agreement), the rights, interests or
obligations hereunder may not be assigned, by operation of law or otherwise,  in
whole or in part,  by the  Company  without  the prior  written  consent  of the
Lender.

         (f) Entire Agreement.  This Agreement  together with Note, the Security
Agreement,  and each  instrument  or other  agreement  executed and delivered in
connection  therewith  (collectively,  "Transaction  Documents")  constitute and
contain the entire  agreement  among the Company and the Lenders  with regard to
the  subject  matter  hereof,  and  supersede  any  and  all  prior  agreements,
negotiations,  correspondence,   understandings  and  communications  among  the
parties, whether written or oral, respecting the subject matter hereof.

         (g) Notices. All notices, requests, demands, consents,  instructions or
other communications required or permitted hereunder shall in writing and faxed,
mailed or  delivered  to each party as  follows:  (i) if to the  Lender,  at 349
Oyster Point Blvd.,  South San Francisco,  CA 94080, or at such other address as
the Lender  shall have  furnished  the  Company  in  writing,  or (ii) if to the
Company,  at One Corporate  Drive,  South San Francisco,  CA, 94080,  or at such
other

                                       7
<PAGE>

address or facsimile number as the Company shall have furnished to the Lender in
writing.  All such notices and  communications  will be deemed effectively given
the earlier of (i) when  received,  (ii) when  delivered  personally,  (iii) one
business day after being  delivered by facsimile  (with  receipt of  appropriate
confirmation),  (iv) one  business day after being  deposited  with an overnight
courier service of recognized standing or (v) four days after being deposited in
the U.S. mail, first class with postage prepaid.

         (h) Severability of this Agreement.  If any provision of this Agreement
shall be judicially  determined  to be invalid,  illegal or  unenforceable,  the
validity,  legality and enforceability of the remaining  provisions shall not in
any way be affected or impaired thereby.

         (i)  Counterparts.  This  Agreement  may be  executed  in  one or  more
counterparts,  each of  which  will be  deemed  an  original,  but all of  which
together will constitute one and the same agreement.  Facsimile copies of signed
signature pages will be deemed binding originals.

                         [Signatures on following page]

                                       8
<PAGE>

      The parties  have  caused  this Loan  Agreement  to be duly  executed  and
delivered by their proper and duly  authorized  officers as of the date and year
first written above.


                                  COMPANY:

                                  RAVEN BIOTECHNOLOGIES, INC.


                                  By:      /s/ George F. Schreiner
                                           -----------------------------------

                                  Name: George F. Schreiner

                                  Title:   Chief Executive Officer



                                  LENDER:

                                  VAXGEN, INC.


                                  By:      /s/ James P. Panek
                                           ------------------------------------

                                  Name: James P. Panek

                                  Title:   President and CEO


                                       9
<PAGE>

                                   SCHEDULE 1

                       SCHEDULE OF ADVANCES UNDER THE NOTE

o   For each month,  the Advance  provided will reflect planned  expenditure for
    the month ahead.  Company shall provide a budget for each month prior to the
    drawdown  date.  Surplus  amounts at the end of each month shall be credited
    against the following month's Advance.

o   For each  month,  the  Advance  may be  provided  in both  cash and  in-kind
    services provided by Lender to Company,  as may be agreed upon by Lender and
    Company pursuant to a Master Services  Agreement ("MSA") to be negotiated in
    good faith prior to  Closing.  Under such MSA,  the in-kind  portion of such
    Advance shall consist of services provided by Lender technical  personnel to
    Company,  charged  at actual  salary  for such  personnel  plus 90% to cover
    fringe benefits and overhead.

o   The figures below represent  good-faith estimates as to total amount of each
    Advance.  These  amounts  will be  corrected  to reflect  actual  experience
    following that date of this Agreement, provided that, under no circumstances
    shall Lender be obligated to loan Company more than $6 million.

    Schedule of Advances:  indicative amounts:


    ($k) Date                  Total


         12.1.07               1,332

         1.1.08                1,355

         2.1.08                1,355

         3.1.08                1,310

         4.1.08                  655

                                       10
<PAGE>

                                   SCHEDULE 2

                                 USE OF PROCEEDS

o   Each Advance shall be used to cover normal operating expenses of Lender.

o   No amount of any  Advance  may be used to cover  severance  expenses,  bonus
    payments or transaction expenses of Lender or its stockholders.

o   No amount of any  Advance  may be used to pre-pay any amount of the VLL Loan
    and no Advance  shall be adjusted in amount for Lender to pre-pay any amount
    of the VLL Loan.  In the event  Lender  determines  at its sole  election to
    pre-pay any amount of the VLL Loan,  Lender shall so notify  Company and VLL
    in  accordance  with the VLL Side  Letter of even date  herewith  among VLL,
    Company and Lender,  which  amount when so paid by Lender  shall be added to
    the Total Loan Amount and be  evidenced  by the Note and  secured  under the
    Security Agreement.

                                       11
<PAGE>

                                   SCHEDULE 3

                                      None.




                                       12
<PAGE>

                                    EXHIBIT A

                                  FORM OF NOTE




<PAGE>


                             SECURED PROMISSORY NOTE


      $6,000,000                                              November  __, 2007



      For value received  RAVEN  BIOTECHNOLOGIES,  INC., a Delaware  corporation
(the  "Company")  promises  to pay  to  VAXGEN,  INC.,  a  Delaware  corporation
("Lender") the principal sum of up to SIX MILLION DOLLARS ($6,000,000.00),  plus
any amounts  paid to Venture  Lending & Leasing IV, Inc. by the Lender on behalf
of the  Company to pay off and  discharge  the VLL Loan (as  defined in the Loan
Agreement),  or such lesser amount as may be advanced hereunder (the "Commitment
Amount"), together with simple interest on the outstanding principal amount from
time to time outstanding  hereunder at the rate of 8% per annum.  Interest shall
commence with the date hereof and shall  continue on the  outstanding  principal
until paid in full or  converted.  Interest  shall be computed on the basis of a
year of 365 days for the actual number of days elapsed.

      1. Loan Agreement.  This note (the "Note") is issued to Lender pursuant to
the terms of that  certain  Loan  Agreement  dated as of November  __, 2007 (the
"Loan Agreement") by and between the Company and Lender.

      2.  Currency.  All payments of interest and  principal  shall be in lawful
money of the  United  States of  America  and  shall be made pro rata  among all
Holders. All payments shall be applied first to accrued interest, and thereafter
to principal.

      3. Secured Note. The  obligations  under this Note shall be secured by the
Collateral, as defined in the Security Agreement attached hereto as Exhibit A.

      4. Payment on Maturity Date.  Subject to Section 5 of the Loan  Agreement,
the entire  outstanding  principal balance and all unpaid accrued interest shall
become fully due and payable on the  Maturity  Date.  As used herein,  "Maturity
Date" means the earliest  of: (i) June 1, 2009,  in the event the Merger has not
closed by April 15,  2008 or such later date as the  parties  may have agreed to
extend the time for closing the Merger under the Merger  Agreement (the "Trigger
Date")  other  than as a result of a breach  by the  Company  under  the  Merger
Agreement as provided in Section 7.1(e) of the Merger  Agreement,  a termination
of the Merger  Agreement as provided in Section 7.1(f) of the Merger  Agreement,
or the Company's  termination of the Merger Agreement pursuant to Section 7.1(j)
of the Merger  Agreement,  (ii) at Lender's  election,  within 10 days following
termination of the Merger Agreement by the Company as provided in Section 7.1(j)
of  the  Merger  Agreement,  (iii)  upon  the  closing  of a  Razor  Acquisition
Transaction (as defined in the Merger  Agreement),  or (iv)  immediately upon an
Event of Default as set forth below.

      5.  Mandatory  Prepayments.  If the Merger  has not closed by the  Trigger
Date, then the Company shall pay Lender (i) 10% of any proceeds  received by the
Company up to $5 million in the aggregate  from any equity or debt  financing or
from any business development transaction, and (ii) 20% of any proceeds received
by the Company in excess of $5 million until all outstanding amounts owing under
the Note shall have been paid in full.  For the  avoidance  of doubt,  by way of
example  only,  in the  event  the  Company  receives  $7  million  in an equity
financing, the Company shall pay the Lender $900,000.

                                       A-1
<PAGE>

      6. Fees.  In the event of any  default  hereunder,  Company  shall pay all
reasonable  attorneys'  fees and court costs incurred by Lender in enforcing and
collecting this Note.

      7. Prepayment. The Company may prepay this Note at any time.

      8. Event of Default.  The  occurrence  of any one or more of the following
shall constitute an "Event of Default":

         (a) Company fails to pay timely any of the  principal  amount due under
this Note on the date the same  becomes due and payable or any accrued  interest
or other  amounts  due  under  this  Note on the date the same  becomes  due and
payable;

         (b) Company shall materially default in its performance of any covenant
under Section 4 of the Agreement;

         (c) Company shall  materially  default in its  performance of any other
covenant under the Agreement,  or under this Note or the Security Agreement,  in
each case which  breach is not cured  within 15 days after  receipt of notice of
such breach from Lender;

         (d) Company shall commit a breach of the Merger  Agreement  which would
permit the  termination  of the Merger  Agreement by Lender  pursuant to Section
7.1(e) of the Merger  Agreement,  whether or not the Merger Agreement is in fact
so terminated;

         (e)  Company  files  any  petition  or  action  for  relief  under  any
bankruptcy,  reorganization,  insolvency or moratorium  law or any other law for
the relief of, or relating to, debtors, now or hereafter in effect, or makes any
assignment  for the  benefit  of  creditors  or takes  any  corporate  action in
furtherance of any of the foregoing; or

         (f) An  involuntary  petition is filed  against  Company  (unless  such
petition is dismissed or discharged  within sixty (60) days under any bankruptcy
statute now or hereafter in effect) or a custodian,  receiver, trustee, assignee
for the benefit of creditors  (or other  similar  official) is appointed to take
possession, custody or control of any property of Company.

      9. Waivers. Company hereby waives demand, notice, presentment, protest and
notice of dishonor.

      10.  Governing Law. This Note shall be governed by and construed under the
laws  of the  State  of  Delaware,  as  applied  to  agreements  among  Delaware
residents,  made and to be  performed  entirely  within  the State of  Delaware,
without giving effect to conflicts of laws principles.

      11.  Subordination.  The  indebtedness  evidenced  by this  Note is hereby
expressly  subordinated,  to the extent and in the manner hereinafter set forth,
in right of payment to the prior payment in full in cash of all of the Company's
obligations  to Venture  Lending  and Leasing  pursuant  that  certain  Loan and
Security  Agreement,  dated as of October 14, 2004, as amended, in an amount not
to exceed $1,500,000 (the "VLL Loan").

                                       A-2
<PAGE>

         (a) Acceleration;  Enforcement Rights.  Prior to the payment in full in
cash of the VLL Loan,  Lender shall have no right to accelerate  the maturity of
the amounts due under this Note or otherwise demand payment thereof,  or enforce
any claim with respect to the amounts due under this Note.

         (b) Other  Indebtedness.  No indebtedness other than that arising under
the VLL Loan shall be senior in any respect to the  indebtedness  represented by
this Note.

         (c) No Impairment.  Subject to the rights,  if any, of VLL with respect
to the VLL Loan,  under this  Section 11 to receive  cash,  securities  or other
properties otherwise payable or deliverable to Lender and the other restrictions
set forth in this Section 11, nothing contained in this Section 11 shall impair,
as between Company and Lender,  the obligation of Company,  subject to the terms
and conditions hereof, to pay to Lender the principal hereof and interest hereon
as and when the same become due and payable or shall  prevent  Lender,  upon the
occurrence of an Event of Default  hereunder from exercising all rights,  powers
and remedies provided herein or by applicable law.

         (d) Lien Subordination. Any lien of Lender on any assets or property of
Company or any proceeds or revenues  therefrom which Lender may have at any time
as  security  for any  amounts  due and  obligations  under  this Note  shall be
subordinate  to all liens granted to VLL with respect to the VLL Loan or by law,
notwithstanding  the date or order of  attachment or perfection of any such lien
or the  provisions of any  applicable  law. Until payment in full in cash of all
amounts  owing under the VLL Loan,  Lender agrees that VLL may dispose of any or
all of the  collateral for the VLL Loan held and perfected by VLL free and clear
of any and all  liens in favor of  Lender  in  accordance  with  applicable  law
including taking title to such collateral after notice to Lender.



                     [Remainder of page intentionally blank]

                                      A-3
<PAGE>


      The Company has caused this Note to be executed  and  delivered  as of the
date first set forth above.


                                         RAVEN BIOTECHNOLOGIES, INC.



                                         By:
                                            ------------------------------------
                                         Name:
                                                --------------------------------
                                         Title:
                                                 -------------------------------



                                       A-4
<PAGE>


                                    EXHIBIT B

                           FORM OF SECURITY AGREEMENT



<PAGE>

                               SECURITY AGREEMENT


      This  Security  Agreement,  dated as of  November  ___,  2007,  ("Security
Agreement"),  is made by and  among  Raven  biotechnologies,  Inc.,  a  Delaware
corporation  ("Grantor")  and VaxGen,  Inc.,  a Delaware  corporation  ("Secured
Party").

                                    RECITALS

      A. Secured  Party has made and may in the future make certain  advances of
money and extend certain financial  accommodation to Grantor (collectively,  the
"Loan") as evidenced by that certain Secured Promissory Note executed by Grantor
in  favor of  Secured  Party  ("Note")  issued  pursuant  to that  certain  Loan
Agreement  dated November __, 2007 by and between Grantor and Secured Party (the
"Loan Agreement").

      B. Secured Party is willing to make the Loan to Grantor, but only upon the
condition,  among others,  that Grantor shall have executed and delivered to the
Secured Party this Security Agreement.

                                    AGREEMENT

      NOW, THEREFORE,  in order to induce the Secured Party to make the Loan and
for other good and valuable consideration, the receipt and adequacy of which are
hereby  acknowledged,   and  intending  to  be  legally  bound,  Grantor  hereby
represents, warrants, covenants and agrees as follows:

      1. Defined Terms. When used in this Security Agreement the following terms
shall have the following  meanings (such  meanings  being equally  applicable to
both the singular and plural forms of the terms defined):

      "Bankruptcy Code" means Title 11 of the United States Code.

      "Collateral"  shall have the meaning assigned to such term in Section 2 of
this Security Agreement.

      "Copyright License" means any agreement,  whether in written or electronic
form,  in which Grantor now holds or hereafter  acquires any interest,  granting
any right in or to any Copyright or Copyright  registration  (whether Grantor is
the licensee or the licensor thereunder) including, without limitation, licenses
pursuant to which  Grantor has obtained the  exclusive  right to use a copyright
owned by a third party.

      "Copyrights" means all of the following now owned or hereafter acquired or
created  (as a work for hire for the  benefit of Grantor) by Grantor or in which
Grantor now holds or hereafter  acquires or receives  any right or interest,  in
whole or in part: (a) all copyrights,  whether registered or unregistered,  held
pursuant  to the laws of the  United  States,  any  State  thereof  or any other
country;  (b)  registrations,  applications,  recordings and  proceedings in the
United States  Copyright Office or in any similar office or agency of the United
States, any State thereof or any other country; (c) any continuations,  renewals
or  extensions  thereof;  (d) any  registrations  to be  issued  in any  pending
applications, and shall include any right or interest in and to work protectable
by any of

                                       B-1
<PAGE>

the foregoing which are presently or in the future owned,  created or authorized
(as a work for hire for the benefit of Grantor) or acquired by Grantor, in whole
or in part; (e) prior versions of works covered by copyright and all works based
upon, derived from or incorporating such works; (f) income, royalties,  damages,
claims and  payments  now and  hereafter  due  and/or  payable  with  respect to
copyrights,  including,  without limitation,  damages, claims and recoveries for
past,  present or future  infringement;  (g) rights to sue for past, present and
future infringements of any copyright; and (h) any other rights corresponding to
any of the foregoing rights throughout the world.

      "Event of Default"  means (i) any failure by Grantor  forthwith  to pay or
perform any of the Secured Obligations,  or (ii) any material  misrepresentation
by Grantor  when made or deemed made in any  representation  or warranty in this
Security  Agreement or any material  breach by Grantor of any covenant set forth
in Section 5 hereof,  provided that Grantor has been given notice of such breach
and has not cured such breach, if curable, within thirty days of such notice.

      "Intellectual Property" means any intellectual property, in any medium, of
any kind or nature whatsoever, now or hereafter owned or acquired or received by
Grantor or in which  Grantor now holds or  hereafter  acquires  or receives  any
right or interest,  and shall include,  in any event, any Copyright,  Trademark,
Patent,  trade secret,  customer list, internet domain name (including any right
related to the registration thereof),  proprietary or confidential  information,
mask work, source,  object or other programming code,  invention (whether or not
patented or patentable),  technical information,  procedure,  design, knowledge,
know-how,  software,  data base, data,  skill,  expertise,  recipe,  experience,
process, model, drawing, material or record.

      "License" means any Copyright License,  Patent License,  Trademark License
or other license of rights or interests,  whether in-bound or out-bound, whether
in written or electronic form, now or hereafter owned or acquired or received by
Grantor or in which  Grantor now holds or  hereafter  acquires  or receives  any
right or interest,  and shall  include any renewals or  extensions of any of the
foregoing thereof.

      "Lien" means any mortgage,  lien, deed of trust, charge, pledge,  security
interest or other encumbrance.

      "Loan Documents" shall have the meaning set forth in Section 6(a) below.

      "Patent  License"  means any  agreement,  whether in written or electronic
form,  in which Grantor now holds or hereafter  acquires any interest,  granting
any right  with  respect  to any  invention  on which a Patent  is in  existence
(whether Grantor is the licensee or the licensor thereunder).

      "Patents"  means  all of the  following  in  which  Grantor  now  holds or
hereafter  acquires any  interest:  (a) all patents of the United  States or any
other country, all registrations and recordings thereof and all applications for
patents  of  the  United  States  or  any  other  country,  including,   without
limitation,  registrations,  recordings  and  applications  in the United States
Patent and  Trademark  Office or in any  similar  office or agency of the United
States,  any State thereof or any other  country;  (b) all patents to issue from
any such applications;  (c) all reissues,  divisions,  continuations,  renewals,
continuations-in-part or extensions thereof; (d) all petty patents,  divisionals
and patents of addition; (e) income, royalties, damages, claims and payments now
and hereafter  due and/or

                                       B-2
<PAGE>

payable with respect to patents, including, without limitation,  damages, claims
and recoveries for past, present or future  infringement;  and (f) rights to sue
for past, present and future infringements of any patent.

      "Permitted Lien" shall have the meaning set forth in the Loan Agreement.

      "Proceeds"  means and includes any  "proceeds," as such term is defined in
Article 9 of the UCC, now or hereafter  owned or acquired or received by Grantor
or in which  Grantor now holds or  hereafter  acquires or receives  any right or
interest,  and shall include,  in any event,  any and all (a) Accounts,  Chattel
Paper, Instruments,  Investment Property, cash or other forms of money, currency
or funds or other property of any nature,  type or land whatsoever payable to or
renewable by Grantor from time to time in respect of the  Collateral,  including
upon the sale, lease, license,  exchange or other disposition of any Collateral,
(b) claims of Grantor against third parties arising out of the  infringements of
rights in any of the  Collateral,  including any claim (i) for past,  present or
future  infringement  of any Patent or Patent  License,  Copyright  or Copyright
License or (ii) for past,  present or future  infringement  or  dilution  of any
Trademark or Trademark License or for injury to the goodwill associated with any
Trademark,  Trademark  registration  or Trademark  licensed  under any Trademark
License, (c) rights arising out of any of the Collateral, and (d) other property
of any nature,  type or kind  whatsoever from time to time paid or payable under
or in connection  with,  collected on, or  distributed on account of, any of the
Collateral.

      "Secured Obligations" means (a) the obligation of Grantor to repay Secured
Party all of the unpaid  principal amount of, and accrued interest on (including
any interest that accrues after the  commencement  of bankruptcy)  the Note, and
(b) the obligation of Grantor to pay any fees,  costs or expenses of the Secured
Party under the Note, the Loan Agreement or this Security Agreement.

      "Security  Agreement"  means this  Security  Agreement  and all  Schedules
hereto, as the same may from time to time be amended, modified,  supplemented or
restated.

      "Trademark License" means any agreement,  whether in written or electronic
form,  in which Grantor now holds or hereafter  acquires any interest,  granting
any right in and to any Trademark or Trademark  registration (whether Grantor is
the licensee or the licensor thereunder).

      "Trademarks"  means any of the  following  in which  Grantor  now holds or
hereafter  acquires any  interest:  (a) any  trademarks,  tradenames,  corporate
names, company names, business names, trade styles,  service marks, logos, other
source or business identifiers,  prints and labels on which any of the foregoing
have appeared or appear,  designs and general  intangibles  of like nature,  now
existing or hereafter  adopted or acquired,  all  registrations  and  recordings
thereof  and  any  applications  in  connection  therewith,  including,  without
limitation,  registrations,  recordings  and  applications  in the United States
Patent and  Trademark  Office or in any  similar  office or agency of the United
States, any State thereof or any other country (collectively,  the "Marks"); (b)
any reissues,  extensions or renewals thereof;  (c) the goodwill of the business
symbolized  by or associated  with the Marks;  (d) income,  royalties,  damages,
claims and payments  now and  hereafter  due and/or  payable with respect to the
Marks, including,  without limitation,  damages, claims and recoveries for past,
present  or future  infringement;  and (e) rights to sue for past,  present  and
future infringements of the Marks.

                                      B-3
<PAGE>

      "UCC" means the Uniform  Commercial Code as the same may from time to time
be in effect in the State of  California  (and each  reference in this  Security
Agreement to an Article thereof (denoted as a Division of the UCC as adopted and
in effect in the State of California)  shall refer to that Article (or Division,
as  applicable)  as from time to time in effect,  which in the case of Article 9
shall  include  and refer to Revised  Article 9 from and after the date  Revised
Article 9 shall become effective in the State of California;  provided, however,
in the event that,  by reason of mandatory  provisions of law, any or all of the
attachment,  perfection or priority of the Secured Party's security  interest in
any  Collateral  is governed by the  Uniform  Commercial  Code as in effect in a
jurisdiction  other than the State of California,  the term "UCC" shall mean the
Uniform  Commercial Code  (including the Articles  thereof) as in effect at such
time in such other  jurisdiction for purposes of the provisions  hereof relating
to such  attachment,  perfection  or priority  and for  purposes of  definitions
related to such provisions.

      In addition, the following terms shall be defined terms having the meaning
set forth  for such  terms in the UCC:  "Account",  "Chattel  Paper"  (including
tangible and electronic  chattel paper),  "Equipment"  (including all accessions
and  additions  thereto),  "Instrument"  and  "Investment  Property"  (including
securities and  securities  entitlements).  Each of the foregoing  defined terms
shall include all of such items now owned, or hereafter acquired, by Grantor.

      2.  Grant of  Security  Interest.  As  collateral  security  for the full,
prompt,  complete and final payment and performance  when due (whether at stated
maturity,  by acceleration  or otherwise) of all the Secured  Obligations and in
order to induce the Secured  Party to cause the Loan to be made,  Grantor,  upon
the  termination of that certain Loan and Security  Agreement and the Supplement
thereto,  both dated as of October 14, 2004,  by and between  Venture  Lending &
Leasing IV, Inc. and Grantor, assigns, conveys, mortgages, pledges, hypothecates
and transfers to the Secured Party a continued, first priority security interest
in all of Grantor's  right,  title and interest in, to and under the  following,
whether  now  owned or  hereafter  acquired,  (all of which  being  collectively
referred to herein as the "Collateral"):

          (a) All Intellectual Property of Grantor;

          (b) All Licenses of the Grantor related to the  Intellectual  Property
of the Grantor; and

          (c) To the extent not otherwise included,  all Proceeds of each of the
foregoing and all accessions to,  substitutions and replacements for and profits
of each of the foregoing.

      Notwithstanding  the  foregoing  provisions  of this Section 2, the grant,
assignment  and  transfer of a security  interest as provided  herein  shall not
extend to, and the term  "Collateral"  shall not  include  any  License in which
Grantor has any right,  title or interest if and to the extent (a) such security
interest  is  prohibited  by or in  violation  of any  law,  rule or  regulation
applicable  to Grantor or (b) such  License  includes a provision  containing  a
restriction on assignment  such that the creation of a security  interest in the
right,  title or interest of Grantor  therein would be prohibited and would,  in
and of itself,  cause or result in a default thereunder  enabling another person
party to such License to enforce any remedy with respect thereto;  provided that
the foregoing  exclusion shall not apply if (i) such prohibition has been waived
or such other person has  otherwise  consented  to the  creation  hereunder of a
security  interest in such  License or (ii) such  prohibition  would be rendered
ineffective  pursuant to Sections 9-407(a) or 9-408(a) of the UCC, as applicable
and as then in effect

                                       B-4
<PAGE>

in any  relevant  jurisdiction,  or any  other  applicable  law  (including  the
Bankruptcy  Code) or principles of equity);  provided  further that  immediately
upon the  ineffectiveness,  lapse or  termination  of any  such  provision,  the
Collateral shall include, and Grantor shall be deemed to have granted a security
interest  in, all its rights,  title and  interests in and to such License as if
such provision had never been in effect; and provided further that the foregoing
exclusion  shall in no way be  construed  so as to limit,  impair  or  otherwise
affect the Secured Party's unconditional  continuing security interest in and to
all rights,  title and interests of Grantor in or to any payment  obligations or
other  rights to receive  monies due or to become due under any such License and
in any such monies and other proceeds of such License.

      3. Rights Of Secured Party; Collection Of Accounts.

          (a)  Notwithstanding  anything contained in this Security Agreement to
the contrary, Grantor expressly agrees that it shall remain liable under each of
its Licenses to observe and perform all the  conditions  and  obligations  to be
observed and  performed by it  thereunder  and that it shall  perform all of its
duties and  obligations  thereunder,  all in accordance with and pursuant to the
terms and  provisions  of each such  License.  Secured  Party shall not have any
obligation  or  liability  under any License by reason of or arising out of this
Security Agreement or the granting to the Secured Party of a lien therein or the
receipt by Secured Party of any payment relating to any License pursuant hereto,
nor shall  Secured  Party be required or  obligated  in any manner to perform or
fulfill any of the  obligations of Grantor under or pursuant to any License,  or
to make any payment,  or to make any inquiry as to the nature or the sufficiency
of any payment received by it or the sufficiency of any performance by any party
under any  License,  or to present  or file any claim,  or to take any action to
collect or enforce any  performance or the payment of any amounts which may have
been assigned to it or to which it may be entitled at any time or times.

          (b)  Secured  Party may at any time,  solely upon the  occurrence  and
during the  continuance of any Event of Default,  notify parties to the Licenses
of  Grantor  that the  right,  title and  interest  of Grantor in and under such
Licenses have been assigned to the Secured Party and that payments shall be made
directly to the Secured Party.  Upon the request of the Secured  Party,  Grantor
shall so notify such parties to such  Licenses.  Upon the  occurrence and during
the continuance of any Event of Default,  the Secured Party may communicate with
such  parties to such  Licenses  to verify  with such  parties,  to the  Secured
Party's  satisfaction,  the existence of, amounts payable under and terms of any
such License.

      4. Representations And Warranties.  Grantor hereby represents and warrants
to the Secured Party that:

          (a) Except for the  security  interest  granted to the  Secured  Party
under this Security Agreement and Permitted Liens, Grantor is the sole legal and
equitable owner of or has rights in each item of the Collateral.

          (b) No effective security agreement,  financing statement,  equivalent
security or lien instrument or continuation  statement  covering all or any part
of the Collateral exists, except such as may have been filed by Grantor in favor
of the  Secured  Party  pursuant  to this  Security  Agreement  and  except  for
Permitted Liens.

                                       B-5
<PAGE>

          (c) Upon the  effectiveness  of the grant in Section 2, this  Security
Agreement  creates  a legal  and valid  security  interest  on and in all of the
Collateral in which Grantor now has rights.

          (d) Grantor's  organizational  identification number is, and the chief
executive  office and the place where Grantor  maintains its records  concerning
the Collateral  are presently  located at the address set forth on the signature
page hereof.  If Grantor is a corporation,  limited liability  company,  limited
partnership,  corporate trust or other registered organization, the State (or if
not  a  state,  the  other   jurisdiction)   under  whose  law  such  registered
organization was organized is set forth on the signature page hereof.

          (e) All Copyrights,  Copyright  Licenses,  Patents,  Patent  Licenses,
Trademarks and Trademark  Licenses now owned, held or in which Grantor otherwise
has any interest are listed on Schedule B attached  hereto.  Grantor shall amend
Schedule B from time to time within  twenty (20)  business days after the filing
of any application  for a Patent,  Trademark or Copyright or the issuance of any
Patent or registration of any Trademark or Copyright to reflect any additions to
or  deletions  from this list.  Except as set forth on  Schedule  B, none of the
Patents, Trademarks or Copyrights has been licensed to any third party.

      5.  Covenants.  Unless the Secured  Party  otherwise  consents in writing,
Grantor covenants and agrees with the Secured Party that from and after the date
of this Security Agreement and until the Secured Obligations have been performed
and paid in full:

          5.1  Disposition  of Collateral.  Grantor shall not sell,  transfer or
otherwise  dispose of any of the  Collateral,  or attempt or  contract to do so,
other than the  granting of  non-exclusive  Licenses in the  ordinary  course of
Grantor's business.

          5.2 Change of Jurisdiction of Organization,  Relocation of Business or
Collateral.  Grantor  shall not  change  its  jurisdiction  of  organization  or
relocate its chief executive  office (except as allowed  pursuant to Section 5.1
immediately  above) from such address  provided to the Secured Party pursuant to
Section 4(d) above without  twenty (20) calendar  days' prior written  notice to
the Secured Party.

          5.3 Limitation on Liens on Collateral.  Grantor shall not, directly or
indirectly,  create,  permit or suffer to exist, and shall defend the Collateral
against and take such other action as is  necessary  to remove,  any Lien on the
Collateral,  except (a) Permitted  Liens and (b) the Lien granted to the Secured
Party under this Security Agreement.

          5.4  Registration  of  Intellectual  Property  Rights.  Grantor  shall
promptly  register or cause to be registered any Copyright,  Patent or Trademark
developed  or  acquired  by Grantor  after the date of this  Security  Agreement
which, individually or in the aggregate, is material to the conduct of Grantor's
business,  with the  United  States  Copyright  Office or Patent  and  Trademark
Office,  as  applicable,  including,  without  limitation,  any additions to the
rights and interests of Grantor  listed on Schedule B hereto,  prior to the sale
or licensing of any product containing such rights and interests.

                                       B-6
<PAGE>

          5.5 Notification Regarding Changes in Intellectual  Property.  Grantor
shall:

          (a)  promptly  advise the Secured  Party of any  subsequent  ownership
right or interest of the Grantor in or to any  Copyright,  Patent,  Trademark or
License not specified on Schedule B hereto and shall permit the Secured Party to
amend such Schedule,  as necessary,  to reflect any addition or deletion to such
ownership rights;

          (b) promptly give Secured Party written notice of any  applications or
registrations  of  Intellectual  Property  rights  filed with the United  States
Patent  and  Trademark  Office,  including  the  date  of  such  filing  and the
registration or application numbers, if any; and

          (c) (i) give  Secured  Party not less than twenty (20)  calendar  days
prior written notice of the filing of any applications or registrations with the
United  States  Copyright  Office,  including  the  title  of such  Intellectual
Property rights to be registered, as such title will appear on such applications
or registrations, and the date such applications or registrations will be filed,
and (ii) prior to the filing of any such  applications or  registrations,  shall
execute such documents as Secured Party may reasonably request for Secured Party
to maintain its perfection and priority in such intellectual  property rights to
be registered by Grantor, and upon the request of Secured Party, shall file such
documents   simultaneously   with  the  filing  of  any  such   applications  or
registrations.  Upon  filing any such  applications  or  registrations  with the
United States  Copyright  Office,  Grantor shall promptly  provide Secured Party
with (x) a copy of such applications or registrations,  without the exhibits, if
any, thereto,  (y) evidence of the filing of any documents  requested by Secured
Party to be filed for Secured Party to maintain the  perfection  and priority of
its security interest in such intellectual  property rights, and (z) the date of
such filing.

          (d) Secured Party may audit Grantor's Intellectual Property to confirm
compliance  with this Section 5.5,  provided such audit may not occur more often
than once per year,  unless an Event of Default has occurred and is  continuing.
If an Event of Default has occurred and is continuing,  Secured Party shall have
the right,  but not the  obligation,  to take, at Grantor's  sole  expense,  any
actions  that  Grantor  is  required  under this  Section  5.5 to take but which
Grantor fails to take, after ten (10) calendar days' notice to Grantor.  Grantor
shall  reimburse  and  indemnify  Secured  Party  for all  reasonable  costs and
reasonable  expenses  incurred in the  exercise of its rights under this Section
5.6.

          5.6  Defense  of  Intellectual   Property.   Grantor  shall:  (i)  use
commercially reasonable efforts to protect, defend and maintain the validity and
enforceability  of the  Copyrights,  Patents and  Trademarks,  (ii) use its best
efforts to detect  infringements  of the Copyrights,  Patents and Trademarks and
promptly advise the Secured Party in writing of material  infringements detected
and  (iii)  use its  best  efforts  to not  allow  any  Copyrights,  Patents  or
Trademarks  to be  abandoned,  forfeited or dedicated to the public  without the
written consent of the Secured Party unless  reasonable  business practice would
determine that any such abandonment is appropriate.

          5.7 Further  Assurances;  Pledge of Instruments.  At any time and from
time to time,  upon the written  request of the Secured  Party,  and at the sole
expense of Grantor,  Grantor shall promptly and duly execute and deliver any and
all such further  instruments  and documents and take such further action as the
Secured  Party may deem  necessary or  desirable to obtain the full  benefits of
this  Security  Agreement,   including,   without  limitation,   (a)  executing,
delivering  and

                                       B-7
<PAGE>

causing to be filed any financing or continuation  statements under the UCC with
respect to the security  interests granted hereby and (b) at the Secured Party's
request,  filing or  cooperating  with the Secured  Party in filing any forms or
other  documents  required  to be  recorded  with the United  States  Patent and
Trademark Office,  United States Copyright Office.  The Secured Party may at any
time and from time to time file financing  statements,  continuation  statements
and amendments thereto that describe the Collateral as described herein or words
of similar effect to continue to perfect the security interest granted hereunder
with  respect  to all or any of the  Collateral  in  accordance  with the  grant
hereof. Any such financing statements, continuation statements or amendments may
be signed by the Secured Party on behalf of Grantor and may be filed at any time
in any  jurisdiction.  Grantor also hereby  authorizes the Secured Party to file
any such financing or continuation statement without the signature of Grantor.

      6. Rights And Remedies Upon  Default.  Beginning on the date which is five
(5) calendar  days after any Event of Default shall have occurred and while such
Event of Default is continuing:

          (a) The Secured Party may exercise all rights and remedies  granted to
the Secured Party under this Security  Agreement,  the Note,  the Loan Agreement
and under any other instrument or agreement securing,  evidencing or relating to
the Secured  Obligations  (collectively,  the "Loan  Documents"),  and all other
rights and  remedies of a secured  party  under the UCC.  Without  limiting  the
generality of the foregoing, Grantor expressly agrees that in any such event the
Secured Party without demand of performance  or other demand,  advertisement  or
notice  of any kind  (except  the  notice  specified  below of time and place of
public or private  sale) to or upon Grantor or any other person (all and each of
which demands,  advertisements  and notices are hereby  expressly  waived to the
maximum extent  permitted by the UCC and other  applicable law), may (i) prepare
for  sale,  advertise  for sale and sell (in the  manner  provided  herein)  the
Collateral,  and in connection with the  liquidation of the Collateral,  use any
Intellectual  Property  used or owned by  Grantor  and (ii)  forthwith  collect,
receive,  appropriate and realize upon the Collateral,  or any part thereof, and
may  forthwith  sell,  assign,  give an option or options to purchase or sell or
otherwise  dispose  of said  Collateral  (or  contract  to do so),  or any  part
thereof,  in one or more  parcels  at public or  private  sale or sales,  at any
exchange or broker's  board or at any Secured  Party's  offices or  elsewhere at
such prices as it may deem commercially reasonable, for cash or on credit or for
future delivery  without  assumption of any credit risk. The Secured Party shall
have the right upon any such public sale or sales,  and, to the extent permitted
by law,  upon any such private sale or sales,  to purchase the whole or any part
of said  Collateral so sold,  free of any right or equity of  redemption,  which
equity of redemption Grantor hereby releases.  The Secured Party shall apply the
net  proceeds  of  any  such  collection,   recovery,  receipt,   appropriation,
realization or sale as provided in Section 6(d),  below and only after so paying
over such net proceeds  and after the payment by the Secured  Party of any other
amount required by any provision of law, the Secured Party shall account for the
surplus, if any, to Grantor. Grantor agrees that the Secured Party need not give
more than twenty (20) calendar  days' notice of the time and place of any public
sale or of the time  after  which a  private  sale may take  place and that such
notice is reasonable  notification of such matters.  Grantor shall remain liable
for any  deficiency if the proceeds of any sale or disposition of its Collateral
are  insufficient to pay all amounts to which the Secured Party is entitled from
Grantor,  Grantor  also being  liable for the  attorney  costs of any  attorneys
employed by the Secured Party to collect such deficiency.

                                       B-8
<PAGE>

          (b)  Grantor  also agrees to pay all fees,  costs and  expenses of the
Secured  Party,  including,  without  limitation,  reasonable  attorneys'  fees,
incurred in connection  with the  enforcement  of any of its rights and remedies
hereunder.

          (c) Grantor hereby waives presentment,  demand,  protest or any notice
(to the maximum  extent  permitted by applicable  law) of any kind in connection
with this Security Agreement or any Collateral.

          (d) The Proceeds of any sale,  disposition or other  realization  upon
all or any part of the  Collateral  shall be distributed by the Secured Party in
the following order of priorities:


          First, to the Secured Party in an amount sufficient to pay in full the
reasonable costs of the Secured Party in connection with such sale,  disposition
or other  realization,  including all fees,  costs,  expenses,  liabilities  and
advances  incurred  or  made  by the  Secured  Party  in  connection  therewith,
including, without limitation, reasonable attorneys' fees;


          Second, to the Secured Party in an amount equal to then unpaid Secured
Obligations; and


          Finally,  upon payment in full of the Secured Obligations,  to Grantor
or its  representatives,  in accordance  with the UCC or as a court of competent
jurisdiction may direct.

      7.  Reinstatement.  This Security Agreement shall remain in full force and
effect and continue to be  effective  should any petition be filed by or against
Grantor for liquidation or  reorganization,  should Grantor become  insolvent or
make an assignment  for the benefit of creditors or should a receiver or trustee
be appointed for all or any significant  part of Grantor's  property and assets,
and shall continue to be effective or be  reinstated,  as the case may be, if at
any  time  payment  and  performance  of the  Secured  Obligations,  or any part
thereof, is, pursuant to applicable law, rescinded or reduced in amount, or must
otherwise  be restored  or  returned by any obligee of the Secured  Obligations,
whether as a "voidable preference,"  "fraudulent  conveyance," or otherwise, all
as though such payment or  performance  had not been made. In the event that any
payment, or any part thereof, is rescinded,  reduced,  restored or returned, the
Secured  Obligations  shall be reinstated and deemed reduced only by such amount
paid and not so rescinded, reduced, restored or returned.

      8. Miscellaneous.

          8.1  Waivers;  Amendments.  None of the  terms or  provisions  of this
Security  Agreement  may be waived,  altered,  modified or amended  except by an
instrument in writing, duly executed by Grantor and the Secured Party.

          8.2  Termination  of this  Security  Agreement.  Subject  to Section 7
hereof, this Security Agreement shall terminate upon the payment and performance
in full of the Secured  Obligations,  and all security  interest  granted hereby
shall  terminate and all rights to the  Collateral  shall revert to the Grantor.
Upon the termination of this Security Agreement, Secured Party shall execute and
deliver to Grantor such documents (including UCC-3 termination statements and/or
the  authorization  to file such UCC-3  termination  statements)  as the Grantor
shall reasonably request to evidence such termination.

                                       B-9
<PAGE>

          8.3 Successor and Assigns. This Security Agreement and all obligations
of  Grantor  hereunder  shall be  binding  upon the  successors  and  assigns of
Grantor,  and shall,  together with the rights and remedies of the Secured Party
hereunder,  inure to the benefit of the Secured Party,  any future holder of any
of the indebtedness under the Note and their respective  successors and assigns.
No  sales  of  participations,  other  sales,  assignments,  transfers  or other
dispositions  of any agreement  governing or instrument  evidencing  the Secured
Obligations  or any  portion  thereof or  interest  therein  shall in any manner
affect the lien granted to the Secured Party hereunder.

          8.4  Governing  Law.  In  all  respects,   including  all  matters  of
construction,  validity and performance, this Security Agreement and the Secured
Obligations  arising  hereunder shall be governed by, and construed and enforced
in accordance with, the laws of the State of California  applicable to contracts
made and  performed  in such state,  without  regard to the  principles  thereof
regarding  conflict of laws,  except to the extent that the UCC provides for the
application of the law of Grantor's State.

                                      B-10
<PAGE>

      IN WITNESS  WHEREOF,  each of the parties  hereto has caused this Security
Agreement to be executed and  delivered  by its duly  authorized  officer on the
date first set forth above.


                                                RAVEN BIOTECHNOLOGIES, INC., as
                                             Grantor

         ADDRESS OF GRANTOR

                                                By:_____________________________

         One Corporate Drive
                                                Printed Name:___________________
   South San Francisco, CA 94080

                                               Title:__________________________

         ORGANIZATIONAL IDENTIFICATION          JURISDICTION OF ORGANIZATION OF
NUMBER OF GRANTOR                            GRANTOR

 ________________________                       Delaware________________________



                                                VAXGEN, INC., as Secured Party



                                                By:_____________________________

                                                Printed Name:___________________

                                                Title:__________________________


                                      B-11
<PAGE>

                                   SCHEDULE A

              LIENS EXISTING ON THE DATE OF THIS SECURITY AGREEMENT


                                       B-12
<PAGE>

                                   SCHEDULE B

                              INTELLECTUAL PROPERTY




                                      B-13