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 BAXTER  INTERATIONAL,
INC., a Delaware corporation ("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;


                                       1.
<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 instruments, in

                                       2.
<PAGE>

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

                                       3.
<PAGE>

such  future  Intellectual  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

                                       5.
<PAGE>

delivered in accordance  with the Security  Agreement at or to their  respective
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 Bank 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 the other  Documents] 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 Finance
                                             ------------------------------
                                       Fax:  (410) 309-4077
                                             ------------------------------


                                       BAXTER INTERNATIONAL, INC.

                                       By /s/ Steven J. Meyer
                                          ---------------------------------
                                             Title: Corp. Treasurer





                                       8.

<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]



                                       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.