PATENT AND TRADEMARK ASSIGNMENT AND SECURITY AGREEMENT

            THIS PATENT AND TRADEMARK  ASSIGNMENT AND SECURITY  AGREEMENT  (this
"Agreement"),  dated as of  November 1, 1999,  is made  between  NORTH  AMERICAN
VACCINE,  INC., a Canadian corporation  ("Assignor"),  and BANK OF AMERICA, N.A.
("Assignee").

            Assignor and Assignee are parties to a Security  Agreement  dated as
of  November 1, 1999 (as  amended,  modified,  renewed or extended  from time to
time, the "Security Agreement"),  which Security Agreement provides, among other
things,  for the  assignment  by Assignor to Assignee,  and grant by Assignor to
Assignee of a security  interest in, certain of Assignor's  property and assets,
including,  without  limitation,  its  patents  and  patent  applications,   its
trademarks, service marks and trade names, and its applications for registration
of such  trademarks,  service  marks  and  trade  names.  Pursuant  to the  Loan
Agreement  Assignor has agreed to execute and deliver this Agreement to Assignee
for filing with the United States  Patent and Trademark  Office (the "PTO") (and
any other relevant  recording systems in any domestic or foreign  jurisdiction),
and as further  evidence of and to effectuate  such assignment of and grant of a
security interest in such patents and patent applications,  trademarks,  service
marks and trade names,  and  applications  for  registration of such trademarks,
service  marks and trade  names,  and the other  general  intangibles  described
herein. Accordingly, Assignor and Assignee hereby agree as follows:

            SECTION 1  DEFINITIONS; INTERPRETATION.

            (a) All  capitalized  terms used in this Agreement and not otherwise
defined  herein  shall  have  the  meanings  assigned  to them  in the  Security
Agreement.

            (b) In this  Agreement,  (i) the  meaning of defined  terms shall be
equally  applicable to both the singular and plural forms of the terms  defined;
and (ii) the captions and headings  are for  convenience  of reference  only and
shall not affect the construction of this Agreement.

            SECTION 2  ASSIGNMENT AND GRANT OF SECURITY INTEREST.

            (a)     As  security  for  the  payment  and   performance   of  the
Obligations  (as defined in the Security  Agreement),  Assignor  hereby assigns,
transfers  and  conveys  and  grants a  security  interest  in and  mortgage  to
Assignee, for security purposes, all of Assignor's right, title and interest in,
to and under the following property,  whether now existing or owned or hereafter
acquired,  developed  or  arising  (collectively,   the  "Intellectual  Property
Collateral"):

            (i)     all  patents and patent  applications,  domestic or foreign,
all licenses  relating to any of the foregoing and all income and royalties with
respect to any licenses (including,  without limitation, such patents and patent
applications  as  described  in SCHEDULE A hereto),  all rights to sue for past,
present  or future  infringement  thereof,  all  rights  arising  therefrom  and
pertaining  thereto  and  all  reissues,  divisions,  continuations,   renewals,
extensions and continuations-in-part thereof;



<PAGE>

            (ii)    all  state  (including  common  law),  federal  and  foreign
trademarks,  service marks and trade names, and applications for registration of
such trademarks,  service marks and trade names, all licenses relating to any of
the  foregoing  and all  income  and  royalties  with  respect  to any  licenses
(including,  without limitation, such marks, names and applications as described
in  SCHEDULE  B  hereto),   whether  registered  or  unregistered  and  wherever
registered,  all  rights to sue for past,  present  or  future  infringement  or
unconsented use thereof, all rights arising therefrom and pertaining thereto and
all reissues, extensions and renewals thereof;

            (iii)   the entire goodwill of or associated with the businesses now
or hereafter  conducted by Assignor  connected with and symbolized by any of the
aforementioned properties and assets;

            (iv)    all  general  intangibles  (as  defined  in the UCC) and all
intangible intellectual or other similar property of the Assignor of any kind or
nature,  associated with or arising out of any of the aforementioned  properties
and assets and not otherwise described above; and

            (v)     all products and proceeds of any and all of the foregoing.

            (a)     This Agreement shall create a continuing  security  interest
in the  Intellectual  Property  Collateral  which shall  remain in effect  until
terminated in accordance with Section 17 hereof.

            (b)     Notwithstanding the foregoing  provisions of this Section 2,
the grant of a security interest as provided herein shall not extend to, and the
term "Intellectual Property Collateral" shall not include, (1) that certain U.S.
Patent No. 5,425,946 which is covered by a security interest in favor of Bankers
Trust Company as evidenced by the filing in the U.S. Patent and Trademark Office
(the "Excluded Patent  Collateral"),  and (2) any general  intangibles of Debtor
(whether owned or held as licensee or lessee, or otherwise),  to the extent that
(i) such general  intangibles are not assignable or capable of being  encumbered
as a matter of law or under the terms of the license,  lease or other  agreement
applicable  thereto (but solely to the extent that any such restriction shall be
enforceable under applicable law), without the consent of the licensor or lessor
thereof or other  applicable  party  thereto and (ii) such  consent has not been
obtained; PROVIDED, HOWEVER, that the foregoing grant of security interest shall
extend to, and the term "Intellectual  Property  Collateral" shall include,  (A)
any  general  intangible  which is an  account  receivable  or a proceed  of, or
otherwise  related to the enforcement or collection of, any account  receivable,
or goods  which  are the  subject  of any  account  receivable,  (B) any and all
proceeds of any general  intangibles which are otherwise  excluded to the extent
that the assignment or  encumbrance  of such proceeds is not so restricted,  and
(C) upon obtaining the consent of any such licensor,  lessor or other applicable
party's consent with respect to any such otherwise excluded general intangibles,
such general intangibles as well as any and all proceeds thereof that might have
theretofore  have been excluded  from such grant of a security  interest and the
term "Intellectual Property Collateral."

            SECTION  3  FURTHER   ASSURANCES;   APPOINTMENT   OF   ASSIGNEE   AS
    ATTORNEY-IN-FACT.  Assignor at its expense  shall  execute and  deliver,  or
    cause to be executed and  delivered,  to Assignee any and all  documents and


                                       2
<PAGE>

    instruments,  in form and substance  satisfactory to Assignee,  and take any
    and all action,  which Assignee may reasonably request from time to time, to
    perfect and continue  perfected,  maintain the priority of or provide notice
    of Assignee's security interest in the Intellectual  Property Collateral and
    to accomplish the purposes of this Agreement.  Assignee shall have the right
    to, in the name of the  Assignor,  or in the name of Assignee or  otherwise,
    without  notice  to or  assent  by the  Assignor,  and the  Assignor  hereby
    irrevocably  constitutes  and  appoints  Assignee  (and  any  of  Assignee's
    officers or employees or agents  designated  by Assignee) as the  Assignor's
    true and lawful attorney-in-fact with full power and authority,  (i) to sign
    the name of the Assignor on all or any of such documents or instruments  and
    perform all other acts that Assignee  deems  necessary or advisable in order
    to perfect or continue perfected, maintain the priority or enforceability of
    or provide  notice of  Assignee's  security  interest  in, the  Intellectual
    Property  Collateral,  and (ii) to execute any and all other  documents  and
    instruments, and to perform any and all acts and things for and on behalf of
    the Assignor,  which  Assignee may deem  necessary or advisable to maintain,
    preserve and protect the Intellectual  Property Collateral and to accomplish
    the purposes of this Agreement,  including (A) to defend,  settle, adjust or
    (after the occurrence of any Event of Default) institute any action, suit or
    proceeding with respect to the Intellectual Property Collateral,  and, after
    the  occurrence of any Event of Default,  (B) to assert or retain any rights
    under any license agreement for any of the Intellectual Property Collateral,
    including  without  limitation  any  rights of the  Assignor  arising  under
    Section 365(n) of the  Bankruptcy  Code, and (C) after the occurrence of any
    Event of Default, to execute any and all applications, documents, papers and
    instruments for Assignee to use the  Intellectual  Property  Collateral,  to
    grant or issue any exclusive or  non-exclusive  license or sub-license  with
    respect to any Intellectual  Property Collateral,  and to assign,  convey or
    otherwise  transfer  title  in  or  dispose  of  the  Intellectual  Property
    Collateral;  PROVIDED,  HOWEVER,  that in no event shall  Assignee  have the
    unilateral  power,  prior to the occurrence and  continuation of an Event of
    Default,  to  assign  any of the  Intellectual  Property  Collateral  to any
    Person,  including  itself,  without the  Assignor's  written  consent.  The
    foregoing shall in no way limit Assignee's rights and remedies upon or after
    the  occurrence  of an Event of Default.  The power of attorney set forth in
    this Section 3, being coupled with an interest,  is  irrevocable  so long as
    this Agreement shall not have terminated in accordance with Section 17.

            SECTION 4  FUTURE RIGHTS.  Except as otherwise  expressly  agreed to
in writing by Assignee,  if and when the Assignor shall obtain rights to any new
patentable  inventions or any new trademarks,  or become entitled to the benefit
of any of the  foregoing,  or obtain  rights or  benefits  with  respect  to any
reissue, division,  continuation,  renewal, extension or continuation-in-part of
any patents or trademarks,  or any improvement of any patent,  the provisions of
Section 2 shall  automatically  apply  thereto  and the  Assignor  shall give to
Assignee prompt notice thereof. Assignor shall do all things deemed necessary or
advisable  by  Assignee  to  ensure  the  validity,  perfection,   priority  and
enforceability  of the security  interests  of Assignee in such future  acquired
Intellectual Property Collateral. Assignor hereby authorizes Assignee to modify,
amend,  or supplement the Schedules  hereto and to reexecute this Agreement from
time to time on  Assignor's  behalf and as its  attorney-in-fact  to include any
such future Intellectual


                                        3
<PAGE>

    Property Collateral and to cause such reexecuted Agreement or such modified,
    amended or supplemented Schedules to be filed with PTO.

            SECTION 5  ASSIGNEE'S   DUTIES.    Notwithstanding   any   provision
contained in this Agreement,  Assignee shall have no duty to exercise any of the
rights,  privileges or powers afforded to it and shall not be responsible to the
Assignor  or any other  Person  for any  failure  to do so or delay in doing so.
Except for the accounting for moneys actually received by Assignee  hereunder or
in connection herewith,  Assignee shall have no duty or liability to exercise or
preserve  any  rights,  privileges  or  powers  pertaining  to the  Intellectual
Property Collateral.

            SECTION 6  REPRESENTATIONS AND WARRANTIES.  Assignor  represents and
    warrants to Assignee that:

            (a) A true  and  correct  list of all of the  existing  Intellectual
Property  Collateral  consisting of U.S. patents and patent  applications and/or
registrations  owned  by the  Assignor,  in whole or in  part,  and  pledged  as
collateral hereunder, is set forth in SCHEDULE A.

            (b) A true  and  correct  list of all of the  existing  Intellectual
Property  Collateral  consisting  of U.S.  trademarks,  trademark  registrations
and/or  applications owned by the Assignor,  in whole or in part, and pledged as
collateral hereunder is set forth in SCHEDULE B.

            (c) All  patents,  trademarks,  service  marks  and  trade  names of
Assignor are subsisting and have not been adjudged  invalid or  unenforceable in
whole or in part.

            (d) All  maintenance  fees  required  to be paid on  account  of any
patents or  trademarks of Assignor  have been timely paid for  maintaining  such
patents and trademarks in force, and, to the best of Assignor's knowledge,  each
of the patents and trademarks  constituting  part of the  Intellectual  Property
Collateral is valid and enforceable.

            (e) To the  best of  Assignor's  knowledge  after  due  inquiry,  no
material  infringement  or  unauthorized  use  presently  is  being  made of any
Intellectual Property Collateral by any Person.

            (f) Except as  otherwise  disclosed  in writing by Debtor to Secured
Party,  Assignor is the sole and exclusive  owner of the  Intellectual  Property
Collateral  and  the  past,   present  and  contemplated   future  use  of  such
Intellectual  Property  Collateral  by Assignor  has not,  does not and will not
infringe or violate any right,  privilege  or license  agreement  of or with any
other Person.

            SECTION 7  COVENANTS.

            (a)  Assignor  will  appear  in  and  defend  any  action,  suit  or
proceeding  which may  affect to a material  extent its title to, or  Assignee's
rights or interest in, the Intellectual Property Collateral.

                                        4
<PAGE>

            (b)  Assignor  will not allow or suffer  any  Intellectual  Property
Collateral to become abandoned,  nor any registration  thereof to be terminated,
forfeited, expired or dedicated to the public.

            (c) Assignor will diligently  prosecute all applications for patents
and   trademarks,   and  file   and   prosecute   any  and  all   continuations,
continuations-in-part, applications for reissue, applications for certificate of
correction and like matters as shall be reasonable and appropriate in accordance
with  prudent  business  practice,  and  promptly  pay any and all  maintenance,
license,  registration and other fees, taxes and expenses incurred in connection
with any Intellectual Property Collateral.

            SECTION 8  ASSIGNEE'S RIGHTS AND REMEDIES.

            (a) Assignee  shall  have all rights and  remedies  available  to it
under the  Security  Agreement,  the other  Documents  and  applicable  law with
respect to the security interests in any of the Intellectual Property Collateral
or any other collateral.  Assignor agrees that such rights and remedies include,
but are not  limited  to, the right of  Assignee  as a secured  party to sell or
otherwise  dispose of its collateral after default pursuant to the UCC. Assignor
agrees that Assignee shall at all times have such royalty free licenses,  to the
extent permitted by law and to the extent of Assignor's rights therein,  for any
Intellectual  Property  Collateral that shall be reasonably  necessary to permit
the  exercise  of any of  Assignee's  rights  or  remedies  upon  or  after  the
occurrence  of an Event of  Default  and  shall  additionally  have the right to
license and/or sublicense any Intellectual Property Collateral upon or after the
occurrence of an Event of Default,  whether general,  special or otherwise,  and
whether  on an  exclusive  or a  nonexclusive  basis,  any of  the  Intellectual
Property  Collateral,  throughout  the world  for such  term or  terms,  on such
conditions,  and in such  manner,  as  Assignee  in its  sole  discretion  shall
determine.  In addition to and without  limiting any of the foregoing,  upon the
occurrence  and during the  continuance  of an Event of Default,  Assignee shall
have the right but shall in no way be obligated  to bring suit,  or to take such
other  action as  Assignee  deems  necessary  or  advisable,  in the name of the
Assignor or  Assignee,  to enforce or protect any of the  Intellectual  Property
Collateral,  in which event the Assignor shall,  at the request of Assignee,  do
any and all lawful acts and execute any and all  documents  required by Assignee
in aid of such enforcement. To the extent that Assignee shall elect not to bring
suit to enforce such Intellectual  Property  Collateral,  Assignor agrees to use
all  reasonable  measures and its  diligent  efforts,  whether by action,  suit,
proceeding  or  otherwise,  to prevent  the  infringement,  misappropriation  or
violations  thereof by others and for that purpose agrees diligently to maintain
any action,  suit or  proceeding  against any Person  necessary  to prevent such
infringement, misappropriation or violation.

            (b) The  cash  proceeds  actually  received  from  the sale or other
disposition or collection of  Intellectual  Property  Collateral,  and any other
amounts  received  in  respect  of  the  Intellectual  Property  Collateral  the
application of which is not otherwise  provided for herein,  shall be applied as
provided in the Security Agreement.

            SECTION 9 NOTICES.  All  notices or other  communications  hereunder
shall be in writing (including by facsimile  transmission) shall be mailed, sent
or delivered in accordance with the Security Agreement at or to their respective



                                       5
<PAGE>

addresses  or  facsimile  numbers set forth  below their names on the  signature
pages  hereof,  or at or to such other  address or facsimile  number as shall be
designated  by any party in a written  notice to the other parties  hereto.  All
such  notices and other  communications  shall be  effective  as provided in the
Security Agreement.

            SECTION 10  NO WAIVER;  CUMULATIVE REMEDIES.  No failure on the part
of Assignee to exercise, and no delay in exercising, any right, remedy, power or
privilege  hereunder shall operate as a waiver thereof,  nor shall any single or
partial  exercise of any such right,  remedy,  power or  privilege  preclude any
other or further  exercise  thereof or the exercise of any other right,  remedy,
power or privilege.  The rights and remedies under this Agreement are cumulative
and not  exclusive  of any  rights,  remedies,  powers and  privileges  that may
otherwise be available to Assignee.

            SECTION 11  COSTS AND EXPENSES; INDEMNITY.

            (a) Assignor  agrees to  pay on demand  all  costs and  expenses  of
Assignee,  including without  limitation all attorneys' fees, in connection with
the enforcement or attempted  enforcement of, and  preservation of any rights or
interests under, this Agreement,  and the assignment,  sale or other disposal of
any of the Intellectual Property Collateral.

            (b) Assignor  hereby  agrees to indemnify  Assignee,  any  affiliate
thereof, and their respective directors,  officers,  employees,  agents, counsel
and other advisors (each an "Indemnified Person") against, and hold each of them
harmless from, any and all liabilities,  obligations,  losses, claims,  damages,
penalties,  actions,  judgments,  suits, costs, expenses or disbursements of any
kind or nature whatsoever,  including, without limitation, reasonable attorneys'
fees and attorneys'  fees incurred  pursuant to 11 U.S.C.,  which may be imposed
on, incurred by, or asserted against any Indemnified Person, in any way relating
to  or  arising  out  of  this  Agreement,  including  in  connection  with  any
infringement or alleged  infringement with respect to any Intellectual  Property
Collateral,  or any action  taken or omitted  to be taken by it  hereunder  (the
"Indemnified  Liabilities");  PROVIDED that Assignor  shall not be liable to any
Indemnified Person for any portion of such Indemnified Liabilities to the extent
they are found by a final decision of a court of competent  jurisdiction to have
resulted from such Indemnified  Person's gross negligence or willful misconduct.
If and to the extent that the foregoing  indemnification  is for any reason held
unenforceable,  Assignor agrees to make the maximum  contribution to the payment
and  satisfaction  of each of the Indemnified  Liabilities  which is permissible
under applicable law.

            (c) Any  amounts  payable  to  Assignee  under  this  Section  11 or
otherwise  under this Agreement if not paid upon demand shall bear interest from
the date of such demand until paid in full,  at the default rate of interest set
forth in the Loan Agreement.

            SECTION 12 BINDING  EFFECT.  This  Agreement  shall be binding upon,
inure to the  benefit of and be  enforceable  by  Assignor,  Assignee  and their
respective successors and assigns.


                                       6
<PAGE>

            SECTION 13  GOVERNING LAW. This Agreement  shall be governed by, and
    construed in accordance  with,  the law of the State of New York,  except to
    the extent that the validity or  perfection of the  assignment  and security
    interests  hereunder in respect of any Intellectual  Property Collateral are
    governed by federal law and except to the extent  that  Assignee  shall have
    greater  rights or remedies  under federal law, in which case such choice of
    New York law shall not be deemed to  deprive  Assignee  of such  rights  and
    remedies as may be available under federal law.

            SECTION 14  AMENDMENT. This Agreement shall not be amended except by
    the written agreement of the parties.

            SECTION 15 SEVERABILITY.  Whenever possible,  each provision of this
    Agreement  shall be  interpreted in such manner as to be effective and valid
    under all applicable laws and  regulations.  If,  however,  any provision of
    this  Agreement  shall be  prohibited  by or  invalid  under any such law or
    regulation in any jurisdiction, it shall, as to such jurisdiction, be deemed
    modified to conform to the minimum  requirements  of such law or regulation,
    or, if for any reason it is not deemed so modified,  it shall be ineffective
    and invalid only to the extent of such  prohibition  or  invalidity  without
    affecting the remaining  provisions  of this  Agreement,  or the validity or
    effectiveness of such provision in any other jurisdiction.

            SECTION 16  COUNTERPARTS.  This  Agreement  may be  executed  in any
    number  of  counterparts  and  by  different   parties  hereto  in  separate
    counterparts,  each of  which  when so  executed  shall be  deemed  to be an
    original and all of which taken  together  shall  constitute but one and the
    same agreement.

            SECTION 17  TERMINATION. Upon payment and performance in full of all
    Obligations,  this  Agreement  shall  terminate and Assignee  shall promptly
    execute and deliver to Assignor such  documents and  instruments  reasonably
    requested by Assignor as shall be necessary to evidence  termination  of all
    security  interests  given by  Assignor  to  Assignee  hereunder,  including
    cancellation  of this  Agreement by written notice from Assignee to the PTO;
    PROVIDED,  HOWEVER, that the obligations of Assignor under Section 11 hereof
    shall survive such termination.

            SECTION 18  SECURITY  AGREEMENT.   Assignor  acknowledges  that  the
    rights and remedies of Assignee  with  respect to the security  interests in
    the Intellectual Property Collateral granted hereby are more fully set forth
    in the Security Agreement and all such rights and remedies are cumulative.

            SECTION 19  NO INCONSISTENT REQUIREMENTS. Assignor acknowledges that
    this  Agreement and the Security  Agreement may contain  covenants and other
    terms and provisions variously stated regarding the same or similar matters,
    and the Assignor  agrees that all such  covenants,  terms and provisions are
    cumulative and all shall be performed and satisfied in accordance with their
    respective terms.


                                        7
<PAGE>


            IN WITNESS  WHEREOF,  the  parties  hereto have duly  executed  this
Agreement, as of the date first above written.



                                     NORTH AMERICAN VACCINE, INC.


                                     By /s/ Lawrence J. Hineline
                                        -----------------------------
                                        Title: Vice-President Finance

                                     10150 Old Columbia Road
                                     Columbia, Maryland  21046
                                     Attn: Vice-President
                                     Fax: (410) 309-4077


                                     BANK OF AMERICA, N.A.


                                     By /s/ Lawrence J. Gordon
                                        -----------------------------
                                        Title: Vice-President

                                     Bank of America Center
                                     700 Louisiana Street,
                                     TX4-213-08-10
                                     Houston, Texas 77002-2700
                                     Attn: Lawrence J. Gordon
                                     Fax: (713) 247-6719


                                        8
<PAGE>


STATE OF Texas   )
                 ) ss
COUNTY OF Harris )


                On November 2, 1999,  before me, Beth L. Erwin,  Notary  Public,
personally appeared Larry J. Gordon,  personally known to me (or proved to me on
the basis of  satisfactory  evidence) to be the person(s)  whose name(s)  is/are
subscribed to the within  instrument  and  acknowledged  to me that  he/she/they
executed  the  same  in  his/her/their  authorized  capacity(ies),  and  that by
his/her/their  signature(s) on the instrument the person(s),  or the entity upon
behalf of which the person(s) acted, executed the instrument.

            WITNESS my hand and official seal.



                                        /s/ Beth L. Erwin
                                        -----------------
                                        Signature


[SEAL]




                                        9
<PAGE>


STATE OF CALIFORNIA         )
                            )  ss
COUNTY OF _________________ )


            On ___________ , before me, _____________, Notary Public, personally
appeared ___________________________, personally known to me (or proved to me on
the basis of  satisfactory  evidence) to be the person(s)  whose name(s)  is/are
subscribed to the within  instrument  and  acknowledged  to me that  he/she/they
executed  the  same  in  his/her/their  authorized  capacity(ies),  and  that by
his/her/their  signature(s) on the instrument the person(s),  or the entity upon
behalf of which the person(s) acted, executed the instrument.

            WITNESS my hand and official seal.




                                        ____________________________________
                                        Signature



[SEAL]






                                       10
<PAGE>

<TABLE>
<CAPTION>

                                                                 SCHEDULE A
------------------------------------------------------------------------------------------------------------------------------------
                                                 PATENTS AND PATENT APPLICATIONS OF ASSIGNOR
------------------------------------------------------------------------------------------------------------------------------------
ISSUED U.S. PATENTS
------------------------------------------------------------------------------------------------------------------------------------
<S>                               <C>                <C>                <C>                  <C>                   <C>
Method for the High Level         Blake, et al.      NVX                08/798,760           February 11, 1997     Notice of
Expression, Purification and                         (co-exclusive      (Notice of Allowance                       Allowance issued
Refolding of the Outer Membrane                      license with PMC)  issued Jan. 1999)                          January 1999
Group B Porin Proteins                                                                                             (fee paid April
                                                                                                                   1999)
------------------------------------------------------------------------------------------------------------------------------------
Method for the High Level         Blake, et al.      NVX & Rockefeller  5,439,808            August 8, 1995        Patent
Expression, Purification and                         University
Refolding of the Outer Membrane                      (co-exclusive
Group B Porin Proteins from                          license with PMC)
Neisseria Meningitidis
------------------------------------------------------------------------------------------------------------------------------------
Method for the High Level         Blake, et al.      NVX                5,747,287            May 5, 1998           Patent
Expression, Purification and                         (co-exclusive
Refolding of the Outer Membrane                      license with PMC)
Group B Porin Proteins from
Neisseria Meningitidis
------------------------------------------------------------------------------------------------------------------------------------
Group A Streptococcal             Blake et al.       NVX & Rockefeller  5,866,135            February 2, 1999      Patent
Polysaccharide Immunogenic                           University
Compositions and Methods
------------------------------------------------------------------------------------------------------------------------------------
Method for the High Level         Blake, et al.      NVX                5,879,686            March 9, 1999         Patent
Expression, Purification and                         (co-exclusive
Refolding of the Outer Membrane                      license with PMC)
Group B Porin Proteins from
Neisseria Meningitidis
------------------------------------------------------------------------------------------------------------------------------------
</TABLE>

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------------
U.S. PATENT APPLICATIONS
------------------------------------------------------------------------------------------------------------------------------------
<S>                                      <C>                     <C>           <C>                <C>                  <C>
Method for the High Level                Tai, et al.             NVX           08/096,181         July 23, 1993        Application
Expression, Purification and
Refolding of the Outer Membrane
Protein P2 from Haemophilus Type b
------------------------------------------------------------------------------------------------------------------------------------
Method for the High Level                Tai, et al.             NVX           08/449,358          May 24, 1995        Application
Expression, Purification and
Refolding of the Outer Membrane
Protein P2 from Haemophilus Type b
------------------------------------------------------------------------------------------------------------------------------------
Antigenic Group B Streptococcus         Michon, et al.           NVX           08/481,883          June 7, 1995        Application
Type II and Type III
Polysaccharide Fragments Having a
2,5-Anhydro-D-Mannose Terminal
Structure and Conjugate Vaccine
Thereof
------------------------------------------------------------------------------------------------------------------------------------
Direct Methods for Molar-Mass          Michon, D'Ambra           NVX           08/753,242       November 22, 1996      Application
Determination of Fragments of
Haemophilus Type b Capsular
Polysaccharides and Vaccine
Preparation
------------------------------------------------------------------------------------------------------------------------------------
Cloning of Non-IgA FC Binding             Tai, Blake             NVX           08/923,992       September 5, 1997      Application
Forms of the Group B Streptococcal
Beta Antigens
------------------------------------------------------------------------------------------------------------------------------------
Antigenic Group B Streptococcus         Michon, et al.           NVX           09/025,225       February 18, 1998      Application
Type II and Type III
Polysaccharide Fragments Having a
2,5-Anhydro-D-Mannose Terminal
Structure and Conjugate Vaccine
Thereof
------------------------------------------------------------------------------------------------------------------------------------

<PAGE>

------------------------------------------------------------------------------------------------------------------------------------
Immunogenic Conjugates Comprising       Blake, et al.            NVX           09/118/180         July 17, 1998        Application
A Group B Meningococcal Porin and
an H. Influenzae Polysaccharide
------------------------------------------------------------------------------------------------------------------------------------
Modified Immunogenic Pneumolysin       Minetti, et al.           NVX           09/120,044         July 21, 1998        Application
Compositions as Vaccines
------------------------------------------------------------------------------------------------------------------------------------
Group A Streptococcal                    Blake et al.           NVX &          09/207,188        December 8, 1998      Application
Polysaccharide Immunogenic                                   Rockefeller
Compositions and Methods                                     University
------------------------------------------------------------------------------------------------------------------------------------
Procedures for the Extraction and       Michon, Blake            NVX           09/221,620       December 23, 1998      Application
Isolation of Bacterial Capsular
Polysaccharides for Use as
Vaccines or Linked to Proteins as
Conjugate Vaccines
------------------------------------------------------------------------------------------------------------------------------------
Gram Positive Bacterial Antigens       Long-Rowe, Blake          NVX           09/399,220       September 17, 1999     Application
and Methods of Purification of the
Streptococcal C-Beta Protein
------------------------------------------------------------------------------------------------------------------------------------
Immunogenic Polysaccharide-Protein      Michon et al.            NVX           09/376,911        August 18, 1999       Application
Conjugate Useful as a Vaccine
Produced Via Conjugation Through a
CZ-3 N-Acyl Portion F A
Polysaccharide
------------------------------------------------------------------------------------------------------------------------------------

</TABLE>

                                      A-1
<PAGE>

<TABLE>
<CAPTION>

---------------------------------------------------------------------------------------------------------------------------
                                                                 SCHEDULE B
---------------------------------------------------------------------------------------------------------------------------
                                                         U.S. TRADEMARKS OF ASSIGNOR
---------------------------------------------------------------------------------------------------------------------------
MARK                               STATUS              APPL NO./     APPL./REGIS. DATE        OWNER OF RECORD
                                                       REGIS. NO.
---------------------------------------------------------------------------------------------------------------------------
     REGISTERED U.S. TRADEMARKS
---------------------------------------------------------------------------------------------------------------------------
<S>                                <C>                 <C>           <C>                      <C>
Globe Design                       Registered          1,932,111     October 31, 1995         North American Vaccine, Inc.
---------------------------------------------------------------------------------------------------------------------------
AMVAX                              Registered          1,967,632     April 16, 1996           North American Vaccine, Inc.
---------------------------------------------------------------------------------------------------------------------------
TRINAVACEL                         Registered          2,101,121     September 30, 1997       American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
TRIVAX                             Registered          2,118,360     December 2, 1997         American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
NAVA                               Registered          2,267,812     August 3, 1999           American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
     PENDING U.S. TRADEMARK APPLICATIONS
---------------------------------------------------------------------------------------------------------------------------
THE IMPORTANCE OF OUR WORK         Pending             75/190,826    October 29, 1996         American Vaccine Corporation
GROWS BIGGER EVERY DAY
---------------------------------------------------------------------------------------------------------------------------
NEISVAC-C                          Pending             Not Avail.    August 26, 1999          American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
NEISIVA                            Pending             Not Avail.    August 26, 1999          American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
MENCIVA                            Pending             Not Avail.    August 26, 1999          American Vaccine Corporation
---------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                      B-1