EXHIBIT 10.22




                      FORM OF PLEDGE AND SECURITY AGREEMENT
                      -------------------------------------

      THIS PLEDGE AND SECURITY  AGREEMENT,  dated as of January 19, 1999, by and
between GENETIC VECTORS,  INC., a Florida corporation  ("PLEDGOR"),  and CAPITAL
RESEARCH LTD., a Delaware corporation (the "PLEDGEE").

      WHEREAS,  Pledgee is the holder of a Promissory  Note (the "NOTE") of even
date herewith made by Pledgor in the original principal amount of $163,500;

      WHEREAS, Pledgee desires to obtain a security interest in certain property
owned by Pledgor; and

      WHEREAS,  as an inducement to Pledgee's  purchase of the Note, Pledgor has
agreed to grant to Pledgee a security interest in and to the Pledged  Collateral
(as hereinafter defined).

      NOW, THEREFORE,  in consideration of the premises and the mutual covenants
herein contained,  and for other good and valuable  consideration,  the adequacy
and receipt for which are hereby  acknowledged,  the parties hereto hereby agree
as follows: 

                                   ARTICLE 1.

                         DEFINITIONS AND INTERPRETATIONS
                         -------------------------------

      Section 1.1.  INTERPRETATIONS.
                    ---------------

      Nothing  herein  expressed or implied is intended or shall be construed to
confer upon any person other than Pledgee any right, remedy or claim under or by
reason hereof. All covenants, stipulations and agreements herein contained by or
on behalf of Pledgee shall be for the sole and exclusive benefit of Pledgee.



<PAGE>

      Section 1.2.  OBLIGATIONS SECURED.
                    -------------------

      The  obligations  secured hereby are the obligations of Pledgor to Pledgee
under the Note sold by Pledgor  to  Pledgee,  in the  maximum  principal  amount
thereof  outstanding from time to time, and any additional amounts payable by or
chargeable to Pledgor thereunder or hereunder (collectively, the "OBLIGATIONS").

                                   ARTICLE 2.

                 PLEDGE AND ADMINISTRATION OF PLEDGED COLLATERAL
                 -----------------------------------------------

      Section 2.1.  PLEDGED COLLATERAL.
                    ------------------

               (a)  Pledgor  hereby pledges  to Pledgee, and  creates in Pledgee
for  its benefit,  a  security interest,  for such time as the Obligations shall
remain outstanding, in and to all of Pledgor's right, title and interest in and
to:
               
                    (i) the property (the "PLEDGED  PROPERTY") listed on EXHIBIT
1 attached hereto (and signed by Pledgor),  including,  without limitation,  any
securities  described therein (which securities are collectively  referred to as
the "PLEDGED SECURITIES"),  now owned by Pledgor, and all machinery,  equipment,
automobiles,  accounts receivable,  inventory and general intangibles,  patents,
patent applications,  licenses and all other intellectual  property rights owned
by or acquired by Borrower on or after the date of this Agreement; and
                  

                    (ii) all products and  proceeds  from the Pledged  Property.
The property pledged in Section 2.1(a)(i) hereof, the Pledged Securities and the
products thereof and the proceeds of all such items are hereinafter collectively
referred  to as the  "Pledged  Collateral."  The  security  interest  granted by
Pledgor to Pledgee in and to the Pledged  Collateral  shall be free and clear of
all  security  interests  and  restrictions  on  transfer  of any kind except as
provided  in  this  Agreement  or as  may  be  imposed  by  applicable  law.


                                       2
<PAGE>

               (b)  Simultaneously  with  the  execution  and  delivery  of this
Agreement, Pledgor shall make, execute, acknowledge, file, record and deliver to
Pledgee  any   documents   reasonably   requested  by  Pledgee  to  perfect  its
first-in-priority  security interest in the Pledged  Collateral.  Simultaneously
with the execution and delivery of this Agreement,  Pledgor shall make, execute,
acknowledge, file, record and deliver to Pledgee such documents and instruments,
including, without limitation,  financial statements,  certificates,  affidavits
and forms as may, in Pledgee's reasonable judgment,  be necessary to effectuate,
complete or perfect, or to continue and preserve, the first-in-priority security
interest  of Pledgee in the  Pledged  Collateral,  and  Pledgee  shall hold such
documents and instruments as secured party,  subject to the terms and conditions
contained herein. 

      Section 2.2.  RIGHTS; INTERESTS; ETC.
                    -----------------------

               (a)  So  long as  no Event of  Default (as  hereinafter  defined)
shall have occurred and be continuing:

                    (i) Pledgor shall be entitled to exercise any and all rights
pertaining  to the Pledged  Collateral  or any part  thereof for any purpose not
inconsistent with the terms hereof; and

                    (ii) Pledgor shall be entitled to receive and retain any and
all  payments  paid or made in respect of the Pledged  Collateral.  

               (b)  Upon  the  occurrence  and  during  the  continuance  of  an
Event in Default:

                    (i)  Subject to Section  2.2(b)(iii)  hereof,  all rights of
Pledgor to exercise the rights which it would  otherwise be entitled to exercise
pursuant  to Section  2.2(a)(i)  hereof and to receive  payments  which it would
otherwise be  authorized  to receive and retain  pursuant to Section  2.2(a)(ii)
hereof shall be suspended,  and all such rights shall thereupon become vested in


                                       3
<PAGE>

Pledgee who shall  thereupon  have the sole right to exercise such rights and to
receive and hold as Pledged Collateral such payments; provided, however, that if
Pledgee  shall become  entitled and shall elect to exercise its right to realize
on the  Pledged  Collateral  pursuant  to  Article V hereof,  then all cash sums
received by Pledgee, or held by Pledgor for the benefit of Pledgee and paid over
pursuant to Section 2.2(b)(ii) hereof,  shall be applied against any outstanding
Obligations.  

                    (ii) All interest,  dividends, income and other payments and
distributions  which are  received  by Pledgor  contrary  to the  provisions  of
Section  2.3(b)(i) hereof shall be received in trust for the benefit of Pledgee,
shall be segregated  from other  property of Pledgor and shall be forthwith paid
over to Pledgee;

                    (iii)  notwithstanding  anything  contained  hereto  to  the
contrary, Pledgor shall retain any voting rights it may have with respect to any
of the Pledged  Securities  until such time as Pledgee is entitled and elects to
exercise its rights to realize on the Pledged  Securities  pursuant to Article V
hereof.

               (c)  Each  of the  following events  shall  constitute a  default
under this Agreement (each an "EVENT OF  DEFAULT"):  

                    (i) any default, whether in whole or in part, shall occur in
the  payment to Pledgee of  principal,  interest  or other item  comprising  the
Obligations as and when due, which default shall continue for a period of thirty
(30) days after the  receipt  of written  notice  thereof  by  Pledgor;  

                    (ii) any default,  whether in whole or in part,  shall occur
in the due observance or performance of any other covenant, term or provision to
be  performed  under this  Agreement by Pledgor,  or the Note,  and all exhibits
thereto which default is not described in any other  subsection of this Section,


                                       4
<PAGE>

and such  default  shall  continue  for a period of thirty  (30) days  after the
receipt of written notice thereof by Pledgor; provided, however, that if Pledgor
shall have  commenced to cure such  default  within such  thirty-day  period and
shall  proceed  continuously  in good faith and with due  diligence to cure such
default, then such period instead shall be sixty (60) days;

                    (iii) Pledgor shall:  (1) make a general  assignment for the
benefit  of its  creditors;  (2) apply for or consent  to the  appointment  of a
receiver,  trustee,  assignee,  custodian,  sequestrator,  liquidator or similar
official  for  itself  or any of its  assets  and  properties;  (3)  commence  a
voluntary case for relief as a debtor under the United States  Bankruptcy  Code;
(4) file with or otherwise  submit to any  governmental  authority any petition,
answer or other document seeking:  (A)  reorganization,  (B) an arrangement with
creditors or (C) to take advantage of any other present or future applicable law
respecting bankruptcy, reorganization, insolvency, readjustment of debts, relief
of debtors,  dissolution or liquidation; (5) file or otherwise submit any answer
or other document admitting or failing to contest the material  allegations of a
petition  or other  document  filed or  otherwise  submitted  against  it in any
proceeding  under any such  applicable  law, or (6) be adjudicated a bankrupt or
insolvent by a court of competent jurisdiction; or

                    (iv) any case, proceeding or other action shall be commenced
against  Pledgor for the purpose of effecting,  or an order,  judgment or decree
shall be entered by any court of competent  jurisdiction  approving (in whole or
in part)  anything  specified in Section  2.2(c)(iii)  hereof,  or any receiver,
trustee, assignee, custodian,  sequestrator,  liquidator or other official shall
be  appointed  with  respect to Pledgor,  or shall be appointed to take or shall
otherwise  acquire  possession  or control of all or a  substantial  part of the
assets and  properties  of  Pledgor,  and any of the  foregoing  shall  continue


                                       5
<PAGE>

unstayed and in effect for any period of sixty (60) days. 

                                  ARTICLE 3.

                          ATTORNEY-IN-FACT; PERFORMANCE
                          -----------------------------

      Section 3.1.  PLEDGEE APPOINTED ATTORNEY-IN-FACT.
                    ----------------------------------

      Upon the  occurrence of an Event of Default and only as long as such Event
of Default shall be  continuing,  Pledgor hereby  appoints  Pledgee as Pledgor's
attorney-in-fact,  with full  authority in the place and stead of Pledgor and in
the name of Pledgor or otherwise,  from time to time in Pledgee's  discretion to
take any action and to execute any instrument  which Pledgee may reasonably deem
necessary to  accomplish  the  purposes of this  Agreement,  including,  without
limitation,  to receive  and  collect all  instruments  made  payable to Pledgor
representing  any  payments  in respect of the  Pledged  Collateral  or any part
thereof and to give full  discharge for the same.  Pledgee may demand,  collect,
receipt for, settle,  compromise,  adjust, sue for, foreclose, or realize on the
Pledged Collateral as and when Pledgee may determine.  To facilitate collection,
Pledgee may notify  account  debtors and obligors on any Pledged  Collateral  to
make payments directly to Pledgee.

      Section 3.2.  PLEDGEE MAY PERFORM.
                    -------------------

      If Pledgor fails to perform any agreement contained herein, Pledgee, at
its option, may itself perform, or cause performance of, such agreement, and the
reasonable expenses of Pledgee incurred in connection therewith shall be payable
by Pledgor under Section 8.3.





                                       6
<PAGE>

                                   ARTICLE 4.

                         REPRESENTATIONS AND WARRANTIES
                         ------------------------------

      Section 4.1.  AUTHORIZATION; ENFORCEABILITY.
                    -----------------------------

      Each of the parties  hereto  represents and warrants that it has taken all
action  necessary to authorize the execution,  delivery and  performance of this
Agreement  and the  transactions  contemplated  hereby;  and upon  execution and
delivery,  this Agreement shall constitute a valid and binding obligation of the
respective party, subject to applicable bankruptcy, insolvency,  reorganization,
moratorium  and similar laws  affecting  creditors'  rights or by the principles
governing the availability of equitable remedies.

      Section 4.2.  OWNERSHIP OF PLEDGED COLLATERAL.
                    -------------------------------

      Pledgor  warrants and represents  that Pledgor is the legal and beneficial
owner of the Pledged  Collateral free and clear of any lien,  security interest,
option or other charge or encumbrance  except for the security  interest created
by this Agreement or as may be imposed by applicable law.

      Section 4.3.  DUE ORGANIZATION.
                    ----------------

      Pledgor warrants and represents that it: (i) is a corporation duly
organized, validly existing and in good standing under the laws of the State of
Florida; (ii) has the corporate power and authority necessary to entitle it to
use its corporate name and to own, lease or otherwise hold its properties and
assets and to carry on its business as presently conducted or proposed to be
conducted; and (iii) is duly qualified and in good standing to do business as
presently conducted or proposed to be conducted.



                                       7
<PAGE>

                                   ARTICLE 5.

                    DEFAULT; REMEDIES; SUBSTITUTE COLLATERAL
                    ----------------------------------------

      Section 5.1.  DEFAULT AND REMEDIES.
                    --------------------

               (a) If an Event of Default  described  in Section  2.2(c)(i)  and
(ii) occurs and is  continuing  for the period set forth  therein,  then in each
such case the Holder may  declare  the  principal  amount to be due and  payable
immediately,  by a  notice  in  writing  to  the  Company,  and  upon  any  such
declaration,  such principal amount shall become immediately due and payable. If
an Event of Default  described  in  Sections  2.2(c)(iii)  or (iv) occurs and is
continuing  for the period set forth therein,  then the principal  amount of the
Note shall automatically  become immediately due and payable without declaration
or other act on the part of any Holder.

               (b) Upon the occurrence of an Event of Default,  the Holder shall
be entitled to receive all distributions with respect to the Pledged Collateral,
to cause the Pledged  Collateral to be  transferred  into the name of Pledgee or
its nominee, to dispose of the Pledged  Collateral,  and to realize upon any and
all rights in the Pledged Collateral then held by Pledgee.

      Section 5.2.  METHOD OF REALIZING UPON THE PLEDGED COLLATERAL:  OTHER
                    -------------------------------------------------------
                    REMEDIES.
                    --------

      Upon the occurrence of an Event of Default,  in addition to any rights and
remedies  available at law or in equity,  the following  provisions shall govern
Pledgee's right to realize upon the Pledged Collateral;
      
               (a) Any item of the  Pledged  Collateral  may be sold for cash or
other value in any number of lots at brokers  board,  public  auction or private
sale and may be sold  without  demand,  advertisement  or  notice  (except  that
Pledgee shall give Pledgor  thirty (30) business  days' prior written  notice of
the time and place or of the time  after  which a private  sale may be made (the
"SALE NOTICE")),  which notice shall in any event be commercially reasonable. At
any sale or sales of the Pledged  Collateral,  Pledgor may bid for and  purchase


                                       8
<PAGE>

the whole or any part of the Pledged  Collateral  and, upon  compliance with the
terms of such sale,  may hold,  exploit and dispose of the same without  further
accountability  to Pledgee.  Pledgor will  execute and  deliver,  or cause to be
executed and  delivered,  such  instruments,  documents,  assignments,  waivers,
certificates,  and  affidavits  and supply or cause to be supplied  such further
information and take such further action as Pledgee  reasonably shall require in
connection  with any such  sale.  

               (b) Any cash being held by Pledgee as Pledged  Collateral and all
cash proceeds  received by Pledgee in respect of, sale of,  collection  from, or
other  realization  upon  all or any  part of the  Pledged  Collateral  shall be
applied as follows:

                     (i) to the  payment of all  amounts  due the Holder for the
expenses  reimbursable to it or them hereunder or owed to it pursuant to Section
8.3 hereof;

                     (ii) to the payment of the amounts  then due and unpaid for
principal of and interest on the Note.

                     (iii)  the  balance,  if  any,  to the  person  or  persons
entitled thereto, including, without limitation, Pledgor.

               (c) In addition to all of the rights and remedies  which  Pledgor
and Pledgee may have pursuant to this Agreement,  Pledgor and Pledgee shall have
all of the rights and remedies provided by law,  including,  without limitation,
those under the Uniform  Commercial  Code.  

               (d) (i) If  Pledgor  fails  to pay  such  amounts  due  upon  the
occurrence  of an Event of  Default  which is  continuing,  then the  Holder may
institute  a  judicial  proceeding  for the  collection  of the  sums so due and
unpaid,  may  prosecute  such  proceeding  to judgment  or final  decree and may


                                       9
<PAGE>

enforce the same against  Pledgor and collect the monies  adjudged or decreed to
be  payable  in the  manner  provided  by law out of the  property  of  Pledgor,
wherever situated.

                     (ii)  Pledgor  agrees  that  it  shall  be  liable  for any
reasonable  expenses  incurred  by the Holder in  connection  with  enforcement,
collection and preservation of the Note,  including,  without limitation,  legal
fees and expenses,  and such amounts shall be deemed  included under Section 8.3
hereof.


      Section 5.3.  PROOFS OF CLAIM.
                    ---------------

               (a) In  case of the  pendency  of any  receivership,  insolvency,
liquidation, bankruptcy, reorganization, arrangement, adjustment, composition or
other judicial  proceeding  relating to Pledgor or the property of Pledgor or of
such other obligor or their creditors,  the Holder  (irrespective of whether the
principal  of the Note shall then be due and payable as therein  expressed or by
declaration or otherwise and  irrespective of whether the Holder shall have made
any demand on Pledgor for the payment of overdue principal, if any, or interest)
shall  be  entitled  and  empowered,  by  intervention  in  such  proceeding  or
otherwise:

                     (i) to file  and  prove a claim  for the  whole  amount  of
principal of the Note and  interest  owing and unpaid in respect of the Note and
to file such other papers or documents as may be necessary or advisable in order
to have the  claims of the  Holder  (including  any claim for the legal fees and
expenses and other expenses paid or incurred by the Holder  permitted  hereunder
and of the Holder allowed in such judicial proceeding), and

                     (ii) to collect and  receive  any monies or other  property
payable or  deliverable  on any such claims and to distribute  the same; and any
custodian,  receiver,  assignee,  trustee,  liquidator,  sequestrator  or  other
similar  official in any such judicial  proceeding is hereby  authorized by each
Holder to make such  payments  to the Holder  and,  in the event that the Holder


                                       10
<PAGE>

shall consent to the making of such payments  directed to the Holder,  to pay to
the Holder any amounts for expenses due it hereunder.

               (b) Nothing  herein  contained  shall be deemed to authorize  the
Holder to  authorize,  consent to or accept or adopt on behalf of any Holder any
plan of  reorganization,  arrangement,  adjustment or composition  affecting the
rights of any Holder  thereof or to  authorize  the Holder to vote in respect of
the claim of any Holder in any such proceeding.

      Section 5.4.  DUTIES  REGARDING PLEDGED  COLLATERAL.
                    -------------------------------------

      Pledgee  shall  have no duty as to the  collection  or  protection  of the
Pledged Collateral or any income thereon or as to the preservation of any rights
pertaining  thereto,  beyond the safe custody and reasonable  care of any of the
Pledged Collateral actually in Pledgee's possession. 

                                   ARTICLE 6.

                              AFFIRMATIVE COVENANTS
                              ---------------------

      Pledgor covenants and agrees that, from the date hereof and until the
Obligations have been fully paid and satisfied, unless Pledgee shall consent
otherwise in writing (as provided in Section 8.4 hereof):

      Section 6.1.  EXISTENCE, PROPERTIES, ETC.
                    ---------------------------

               (a) Pledgor shall do, or cause to be done, all things, or proceed
with due diligence with any actions or courses of action, that may be reasonably
necessary  (i) to  maintain  its due  organization,  valid  existence  and  good
standing under the laws of its state of incorporation,  and (ii) to preserve and
keep in full force and effect all qualifications,  licenses and registrations in
those  jurisdictions in which the failure to do so could have a Material Adverse
Effect (as defined in this  Section  6.1(a));  and (b) Pledgor  shall not do, or
cause to be done,  any act  impairing  its  corporate  power or authority (i) to
carry on its  business  as now  conducted,  and (ii) to execute or deliver  this


                                       11
<PAGE>

Agreement or any other document  delivered in connection  herewith  (which other
loan instruments  collectively  shall be referred to the "LOAN  INSTRUMENTS") to
which it is or will be a party, or perform any of its  obligations  hereunder or
thereunder.  For purpose of this Agreement,  the term "MATERIAL  ADVERSE EFFECT"
shall mean any  material  and adverse  affect,  whether  individually  or in the
aggregate,  upon (a)  Pledgor's  assets,  business,  operations,  properties  or
condition, financial or otherwise; (b) the ability of Pledgor to make payment as
and  when  due of all  or any  part  of  the  Obligations;  or (c)  the  Pledged
Collateral.  

      Section 6.2.  ACCOUNTS AND REPORTS.
                    --------------------

      Pledgor shall maintain a standard  system of accounting in accordance with
generally accepted accounting  principles  consistently  applied and provide, at
its sole expense, to Pledgee the following:

               (a)  as  soon  as  available,  a  copy  of any  notice  or  other
communication  alleging any nonpayment or other material  breach or default,  or
any  foreclosure or other action  respecting any material  portion of its assets
and properties, received respecting any of the indebtedness of Pledgor in excess
of $15,000  (other  than the  Obligations),  or any demand or other  request for
payment under any guaranty, assumption,  purchase agreement or similar agreement
or arrangement respecting the indebtedness or obligations of others in excess of
$15,000,  including  any received from any person acting on behalf of the Holder
or beneficiary thereof; and

               (b)  within  five (5)  business  days  after  the  making of each
submission  or  filing,  a copy of any  report,  registration  statement,  proxy
statement,  financial statement,  notice or other document,  whether periodic or
otherwise, submitted to the shareholders of Pledgor, or submitted to or filed by
Pledgor  with  any  governmental   authority  involving  or  affecting  (i)  any
registration  of  Pledgor  or its  securities;  (ii)  Pledgor  that could have a
Material  Adverse Effect;  (iii) the  Obligations;  (iv) any part of the Pledged


                                       12
<PAGE>

Collateral or (v) any of the transactions  contemplated in this Agreement or the
Loan  Instruments,  including,  without  limitation,  those  submitted  or filed
pursuant to the Securities Act of 1933, as amended,  and the Securities Exchange
Act of 1934, as amended.

      Section 6.3.  MAINTENANCE  AND  INSURANCE.
                    ---------------------------

               (a) Pledgor shall maintain or cause to be maintained,  at its own
expense,  all of its assets and  properties in good working order and condition,
making all necessary repairs thereto and renewals and replacements thereof.

               (b) Pledgor shall maintain or cause to be maintained,  at its own
expense, insurance in form, substance and amounts (including deductibles), which
Pledgor deems reasonably necessary to Pledgor's business, (i) adequate to insure
all assets and  properties  of Pledgor,  which  assets and  properties  are of a
character  usually  insured by persons  engaged in the same or similar  business
against loss or damage  resulting  from fire,  flood,  hurricanes or other risks
included in an extended coverage policy; (ii) against public liability and other
tort claims  that may be  incurred  by Pledgor;  (iii) as may be required by the
Loan  Instruments or applicable  law and (iv) as may be reasonably  requested by
Pledgee,  all with adequate,  financially sound and reputable insurers,  and all
naming  Pledgee  as an  additional  insured  and  loss  payee  under a  standard
mortgagee's endorsement as Pledgee's interest may appear.

      Section 6.4.  CONTRACTS AND OTHER  COLLATERAL.
                    -------------------------------

      Pledgor shall perform all of its obligations under or with respect to each
instrument,  receivable,  contract and other intangible  included in the Pledged
Collateral to which Pledgor is now or hereafter  will be party on a timely basis
and  in  the  manner  therein  required,  including,  without  limitation,  this
Agreement;  and  Pledgor  shall  endorse  all  of  its  rights  under  all  such


                                       13
<PAGE>

instruments,  agreements  and  other  receivable  on a timely  basis to the full
extent permitted by applicable law.

      Section 6.5.  DEFENSE OF  COLLATERAL,  ETC.
                    -----------------------------

      Pledgor  shall defend and enforce its right,  title and interest in and to
any part of: (a) the  Pledged  Collateral;  and (b) if not  included  within the
Pledged Collateral, those assets and properties whose loss could have a Material
Adverse Effect,  Pledgor shall defend Pledgee's right, title and interest in and
to each and every part of the  Pledged  Collateral,  each  against all manner of
claims and demands on a timely basis to the full extent  permitted by applicable
law.

      Section 6.6.  PAYMENT OF DEBTS,  TAXES,  ETC.
                    -------------------------------

      Pledgor shall pay, or cause to be paid, all of its  indebtedness and other
liabilities  and perform,  or cause to be performed,  all of its  obligations in
accordance with the respective terms thereof, and pay and discharge, or cause to
be paid or discharged, all taxes, assessments and other governmental charges and
levies  imposed upon it, upon any of its assets and  properties on or before the
last day on which the same may be paid without penalty, as well as pay all other
lawful claims (whether for services, labor, materials, supplies or otherwise) as
and when due; provided,  however,  that it shall not constitute a breach of this
paragraph  if Pledgor  fails to perform any such  obligation  or to pay any such
indebtedness or other liability (except for the Obligations),  tax,  assessment,
or governmental or other charge, levy or claim (i) if the effect of such failure
to pay or perform will not (A) accelerate the maturity thereof,  or of any other
debt or  obligation  of  Pledgor,  or (B)  subject  any part of the  assets  and
properties of Pledgor to sale or forfeiture.


                                       14
<PAGE>

                                  ARTICLE 7.

                               NEGATIVE COVENANTS
                               ------------------

      Pledgor  covenants  and  agrees  that,  from the  date  hereof  until  the
Obligations  have been fully paid and  satisfied,  unless  Pledgee shall consent
otherwise in writing:

      Section 7.1.  INDEBTEDNESS.
                    ------------

      Pledgor shall not directly or indirectly permit,  create,  incur,  assume,
permit to exist,  increase,  renew or  extend  on or after the date  hereof  any
indebtedness  on its  part,  including  commitments,  contingencies  and  credit
availabilities,  or apply  for or  offer  or  agree to do any of the  foregoing,
except  that  Pledgor  may incur or permit to exist:  (a)  indebtedness  owed to
Pledgee;  (b)  indebtedness   incurred  in  the  ordinary  course  of  business,
including,   without   limitation,   to   suppliers,   distributors,   carriers,
materialmen,  laborers,  counsel,  accountants,  advisors, sellers or lessors of
machinery and equipment  and real estate  acquired or leased in connection  with
Pledgor's  business  in an amount not to exceed  $250,000  at any time;  and (c)
other indebtedness expressly subordinated to the obligations by such creditor.
   
      Section 7.2.  LIENS AND ENCUMBRANCES.
                    ----------------------

      Pledgor shall not directly or indirectly make,  create,  incur,  assume or
permit to exist any assignment,  pledge,  mortgage,  security  interest or other
lien or  encumbrance  of any nature in, to or  against  any part of the  Pledged
Collateral,  or offer or agree to do so, or own or  acquire  or agree to acquire
any  asset  or  property  of any  character  subject  to  any  of the  foregoing
encumbrances  (including any conditional  sale contract or other title retention
agreement),  or assign,  pledge or in any way  transfer or encumber its right to
receive  any  income  or other  distribution  or  proceeds  from any part of the
Pledged Collateral,  or enter into any sale-leaseback  financing  respecting any
part of the Pledged  Collateral  as lessee,  or cause or assist the inception or
continuation  of any of the  foregoing;  provided,  however,  that the foregoing


                                       15
<PAGE>

restrictions  shall not prohibit (to the extent otherwise not prohibited by this
Agreement):  

               (a) liens for taxes, assessments, governmental charges, levies or
claims  described in Section 6.7, if payment  thereof shall not then be required
to be made by this Section 7.2;

               (b) liens of  carriers,  warehousemen,  mechanics,  laborers  and
materialmen incurred in the ordinary course of business,  so long as there shall
have been set aside on the books of Pledgor  such  reserve,  if any, as shall be
required by generally accepted accounting principles;

               (c)  liens  incurred  in  the  ordinary  course  of  business  in
connection  with  workers'  compensation,   unemployment  insurance,   statutory
obligation  or  social  security  legislation,  or for any  purpose  at the time
required by law as a condition  precedent to the  transaction of business or the
exercise of any of the privileges or licenses of Pledgor;

               (d) liens  incurred in respect of attachments  discharged  within
thirty  (30) days from the making  thereof or  judgments  or awards in force for
less than thirty (30) days or with respect to which  Pledgor in good faith shall
be  prosecuting  an appeal or proceeding  for review and with respect to which a
stay of execution  upon appeal or proceeding  for review shall have been secured
if required;

               (e) the  security  interests  and other  liens  and  encumbrances
granted from time to time to Pledgee; 

               (f) with respect to  indebtedness  permitted  under  Section 7.1,
liens  incurred in respect of any  financing  of Pledgor's  inventory,  accounts
receivable,  machinery, equipment and automobiles with a bank or other financial
institution,  provided  that  the loan  instruments  evidencing  such  financing


                                       16
<PAGE>

expressly  provide that any lien arising from such  financing is  subordinate to
the first security interest hereunder and, in the event of a default thereunder,
no  collection  of the  principal,  interest  and  other  charges  and  expenses
thereunder will be made until the full payment of the Obligations,  or otherwise
as may be acceptable to the Holder;

               (g) liens  incurred  in respect of  indebtedness  on the  Pledged
Collateral  which  are  subordinated  to the  Obligations  by  such  creditor(s)
executing  the  Subordination  Agreement;  and  which  are  subordinated  to the
Obligations, or otherwise as may be acceptable to Pledgee in its sole discretion
and as to which it consents in writing; and

               (h) with respect to indebtedness  permitted under Section 7.1 and
subject to the  limitations  set forth in Section 7.1, liens incurred in respect
of indebtedness on machinery,  equipment and automobiles  purchased or leased by
Pledgor  after the date of the  execution  and  delivery  of this  Agreement  by
Pledgor. 

                                   ARTICLE 8.

                                  MISCELLANEOUS
                                  -------------

      Section 8.1.  NOTICES.
                    -------
      
      All  notices or other  communications  required or  permitted  to be given
pursuant to this  Agreement  shall be in writing and shall be considered as duly
given on:  (a) the date of  delivery,  if  delivered  in person,  by  nationally
recognized  overnight  delivery  service or (b) three (3) days after  mailing if
mailed from within the  continental  United  States by  registered  or certified
mail,  return receipt requested to the party entitled to receive the same, if to
Pledgor, Genetic Vectors, Inc., 5201 N.W. 77th Avenue, Suite 100, Miami, Florida
33166,  Attention:  Mead M. McCabe, Jr., with a copy to Clayton E. Parker, Esq.,
Kirkpatrick  & Lockhart  LLP,  201 S.  Biscayne  Boulevard,  20th Floor,  Miami,
Florida 33131 and if to Pledgee, at the addresses shown on the books of Pledgor.


                                       17
<PAGE>

Any party may change its address by giving notice to the other party stating its
new address.  Commencing  on the 10th day after the giving of such notice,  such
newly  designated  address shall be such party's  address for the purpose of all
notices or other  communications  required or permitted to be given  pursuant to
this Agreement.

      Section 8.2.  SEVERABILITY.
                    ------------

      If any provision of this Agreement shall be held invalid or unenforceable,
such  invalidity  or  unenforceability  shall attach only to such  provision and
shall not in any  manner  affect or render  invalid or  unenforceable  any other
severable  provision of this Agreement,  and this Agreement shall be carried out
as if any such invalid or unenforceable provision were not contained herein.

      Section 8.3.  EXPENSES.
                    --------

      In the  event of an Event of  Default,  Pledgor  will pay to  Pledgee  the
amount of any and all reasonable  expenses,  including the  reasonable  fees and
expenses of its  counsel,  which  Pledgee or the Holder may incur in  connection
with: (i) the custody or preservation of, or the sale, collection from, or other
realization  upon,  any  of  the  Pledged  Collateral;   (ii)  the  exercise  or
enforcement  of any of the rights of Pledgee  hereunder  or (iii) the failure by
Pledgor to perform or observe any of the provisions hereof. 

      Section 8.4.  WAIVERS, AMENDMENTS,  ETC.
                    --------------------------

      Pledgee's  delay or  failure  at any time or times  hereafter  to  require
strict performance by Pledgor of any undertakings, agreements or covenants shall
not waiver,  affect,  or diminish any right of Pledgee  under this  Agreement to
demand strict compliance and performance herewith.  Any waiver by Pledgee of any
Event of Default  shall not waive or affect any other Event of Default,  whether
such Event of Default is prior or subsequent  thereto and whether of the same or


                                       18
<PAGE>

a different type. None of the undertakings,  agreements and covenants of Pledgor
contained in this  Agreement,  and no Event of Default,  shall be deemed to have
been waived by Pledgee, nor may this Agreement be amended,  changed or modified,
unless  such  waiver,  amendment,  change or  modification  is  evidenced  by an
instrument in writing specifying such waiver, amendment,  change or modification
and signed by the Holder.

      Section 8.5.  CONTINUING SECURITY INTEREST.
                    ----------------------------

      This Agreement shall create a continuing  security interest in the Pledged
Collateral and shall:  (i) remain in full force and effect until payment in full
of the obligations or the conversion of all of the Note as provided therein; and
(ii) be binding upon Pledgor and its  successors  and (iii) inure to the benefit
of  Pledgee  and its  successors  and  permitted  assigns.  Upon the  payment or
satisfaction in full of the Obligations, or such conversion of the Note, Pledgor
shall  be  entitled  to the  return,  at its  expense,  of such  of the  Pledged
Collateral as shall not have been sold,  returned in accordance with Section 5.2
hereof or otherwise applied pursuant to the terms hereof.

      Section 8.6.  APPLICABLE LAW: JURISDICTION.
                    ----------------------------

      This Agreement and the rights of the parties  hereunder  shall be governed
by and  construed in accordance  with the laws of the State of Florida,  without
regard to its conflicts of law principles. Pledgee and Pledgor hereto: (i) agree
that any legal  suit,  action or  proceeding  arising out of or relating to this
Agreement  shall be  instituted  only in a federal or state court in  Miami-Dade
County,  Florida;  (ii) waive any objection which they may now or hereafter have
to the laying of the venue of any such  suit,  action or  proceeding;  and (iii)
irrevocably  submit  to the  jurisdiction  of any  federal  or  state  court  in
Miami-Dade  County,  Florida,  in any such suit, action or proceeding,  but such
consent shall not  constitute a general  appearance or be available to any other
person who is not a party to this  Agreement.  Pledgee and Pledgor  hereto agree
that the mailing of any process in any suit,  action or proceeding in accordance


                                       19
<PAGE>

with the notice  provisions of this Agreement shall constitute  personal service
thereof.  

      Section 8.7.  ENTIRE  AGREEMENT.  

      This  Agreement  constitutes  the entire  agreement  among the parties and
supersedes any prior agreement or  understanding  among them with respect to the
subject matter hereof. 

      Section 8.8.  NUMBER AND GENDER.
                    -----------------

      Wherever  from the  context it appears  appropriate,  each term  stated in
either the singular or the plural shall include the singular and the plural, and
pronouns stated in either the masculine, the feminine or the neuter gender shall
include the masculine, feminine and neuter.

      Section 8.9.  COUNTERPARTS.
                    ------------

      This  Agreement  may be executed in  counterparts,  both of which shall be
deemed  an  original  but  both of  which  shall  constitute  one  and the  same
instrument. In addition, this Agreement may contain more than one counterpart of
the  signature  page and this  Agreement may be executed by the affixing of such
signature  pages  executed by the parties to one copy of the  Agreement;  all of
such  counterpart  signature  pages shall be read as though one,  and they shall
have the same force and effect as though all of the  signers had signed a single
signature page.


                                       20
<PAGE>

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

                                    GENETIC VECTORS, INC.

                                    By:_________________________________________
                                    Title:______________________________________


                                    CAPITAL RESEARCH LTD.

                                    By:_________________________________________
                                    Title:______________________________________






                                       21