<PAGE> 1

               COMMON STOCK AND WARRANT PURCHASE AGREEMENT


        THIS COMMON STOCK AND WARRANT PURCHASE AGREEMENT (this "Agreement"),
is entered into as of October 30, 1998, by CISTRON BIOTECHNOLOGY, INC., a 
Delaware corporation (the "Company") and PASTEUR MeRIEUX SERUMS & VACCINS, 
S.A., a societe anonyme organized under the Laws of France (the 
"Purchaser").

        WHEREAS, the Company has authorized the sale and issuance to Purchaser
of 1,333,333 shares of Common Stock of the Company (the "Shares") and a 
warrant to purchase 666,667 shares of Common Stock at $0.25 per share, 
subject to adjustment in the form of Exhibit A hereto (the "Warrant") for 
the aggregate purchase price of $1,000,000.

        WHEREAS, the Company desires to issue and sell the Shares and Warrant
to the Purchaser, and Purchaser desires to purchase the shares, on the terms 
and conditions set forth herein; and

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

                             ARTICLE 1

                        SALE AND PURCHASE

SECTION 1.1     SALE AND PURCHASE.   Upon the terms and subject to the
conditions hereof, the Company hereby issues and sells to the Purchaser, and
the Purchaser purchases and accepts from the Company, the Shares and Warrant. 

                              ARTICLE 2

                  CLOSING, DELIVERY AND PAYMENT

SECTION 2.1     CLOSING.  The closing of the sale and purchase of the Shares
under this Agreement (the "Closing") has been held on the date hereof at the
principal offices of the Company, 10 Bloomfield Avenue, Pine Brook, New 
Jersey  07058.

SECTION 2.2     DELIVERY.  At the Closing, the Company delivered to the
Purchaser one or more stock certificates registered in the name of the
Purchaser representing the Shares to be purchased hereunder, the Warrant,
the registration rights agreement in the form of Exhibit B hereto (the 
"Registration Rights Agreement") and the other documents required to be 
delivered pursuant to Article 6 and the Purchaser paid the aggregate 
purchase price for the Shares and Warrant of $1,000,000 by wire transfer of 
immediately available funds delivered in accordance with the Company's 
instructions and delivered the other documentation to the Company required 
pursuant to Article 6.

                                -1-
<PAGE>2
                             ARTICLE 3

                REPRESENTATIONS AND WARRANTIES OF THE COMPANY

        The Company hereby represents and warrants to the Purchaser that,
except as disclosed in writing to the Company in a disclosure schedule
previously delivered by the Company to the Purchaser (the "Disclosure
Schedule"):

SECTION 3.1     ISSUER'S ORGANIZATION, GOOD STANDING AND QUALIFICATION.  The
Company is a corporation duly organized, validly existing and in good 
standing under the laws of the State of Delaware, and has all requisite 
corporate power and authority to own, operate and lease its properties and 
to carry on its business as presently conducted and as described in the 
Company's Annual Report on Form 10-K for the fiscal year ended June 30, 
1998 (the "Company 10-K for 1998") as filed with the United States 
Securities and Exchange Commission (the "SEC").  The Company is duly 
qualified as a foreign corporation and is in good standing in each 
jurisdiction where the character of the property owned or leased by it or 
the nature of its activities makes such qualification necessary, except for 
those jurisdictions where the failure to do so would not, individually or 
in the aggregate, have a material adverse effect on the business or
financial condition or operations of the Company.

SECTION 3.2     ISSUER'S POWER AND AUTHORITY.  (a) The Company has all
requisite power and authority to execute and deliver this Agreement and to
perform its obligations hereunder and to consummate the transactions
contemplated hereby.  The execution, delivery and performance by the Company
of this Agreement and the Warrant and the consummation by the Company of the 
transactions contemplated hereby have been duly authorized and approved by 
the Company's Board of Directors and no further action on the part of the 
Company or its stockholders is necessary to authorize the execution, 
delivery and performance of this Agreement, the Warrant or the consummation 
by the Company of the transactions contemplated hereby.  This Agreement, 
the Warrant and the Registration Agreement have been duly executed and 
delivered by the Company and constitute the valid and binding obligation of 
the Company, enforceable against the company in accordance with their 
respective terms, except as enforcement thereof (i) may be limited by 
bankruptcy, insolvency, reorganization, fraudulent conveyance, moratorium 
or other similar laws relating to or affecting enforcement of creditors' 
rights generally, or (ii) is subject to general principles of equity 
(regardless of whether enforcement is considered in a proceeding in equity 
or at law).

SECTION 3.3     NO CONFLICT, CONSENTS.

(a)     No Conflict.  The execution and delivery of this Agreement by the
Company does not, and the performance of this Agreement and the consummation
of any of the transactions contemplated by this Agreement by the Company will
not, directly or indirectly (with or without notice or lapse of time):

        (i)   contravene, conflict with or result in a violation of (A) any of
the provisions of the certificate of incorporation or bylaws of the Company, or
(B) any resolution adopted by the Company's Board of Directors;

                                   -2-
<PAGE>3

        (ii)  contravene, conflict with or result in a violation of, any law,
rule, regulation or order binding upon the Company or any of the properties or
assets owned or used by the Company;

        (iii) contravene, conflict with or result in a violation of any of the
terms or requirements of any governmental authorization that is held by the
Company or that otherwise relates to the business of, or any of the properties
or assets owned or used by, the Company;

        (iv)  contravene, conflict with or result in a violation or breach of,
or result in a default under, any provision of any material contract to which
the Company is a party, or give any person or entity the right to (A) declare a
default or exercise any remedy under any such contract, (B) accelerate the 
maturity or performance of any such contract, or (C) cancel, terminate, 
amend or modify any such contract; or

        (v)  result in the imposition or creation of any lien or other
encumbrance on or with respect to any property or asset owned or used by the
Company.

(b)     Consents.  The execution and delivery of this Agreement does not, and
the performance of this Agreement will not, require any filing with or the 
giving any notice to, or obtaining the consent from, any person, entity or 
governmental authority, except for applicable requirements, if any, of (i) 
the Securities Act of 1933, as amended (the "Securities Act"), (ii) the 
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and (iii) 
state securities or "blue sky" laws.

SECTION 3.4     REPORTS; FINANCIAL STATEMENTS; LIABILITIES.

(a)     The Company has filed all required forms, reports and documents with
the SEC required to be filed by it with respect to all periods commencing
since July 1, 1996 (the "SEC Reports"), all of which have complied in all 
material respects with all applicable requirements of the Securities Act 
and the Exchange Act, as the case may be, and the rules and regulations 
promulgated thereunder.  None of such forms, reports or documents 
(including the financial statements included therein, which are dealt with 
in the following paragraph), at the time filed, contained any untrue 
statement of a material fact or omitted to state a material fact required 
to be stated therein or necessary in order to make the statements therein, 
in light of the circumstances under which they were made, not misleading.  
There are no material contracts or documents of the Company required to be 
filed as exhibits to the SEC Reports by the Securities Act or the Exchange
Act, as the case may be, or the rules and regulations promulgated thereunder
that have not been so filed.

(b) The audited financial statements and unaudited interim financial statements 
of the Company included in the SEC Reports (the "Financial Statements") 
were prepared in accordance with generally accepted accounting principles 
applied on a consistent basis throughout the periods covered (except as may 
be indicated therein or in the notes thereto or, in the case of unaudited 
interim statements, to the extent they may not include footnotes or may be 
condensed or summary financial statements).  The Financial Statements 
fairly present the financial position to the Company as at the respective 
dates thereof and the results of operations and cash flows of the Company 
for the periods covered thereby, subject, in the case of unaudited interim 
financial
                                -3-
<PAGE>4

statements, to normal and recurring year-end adjustments, which
were not and are not expected, individually or in the aggregate, to be 
material in amount).

SECTION 3.6     ABSENCE OF CERTAIN CHANGES.  Since June 30, 1998, there has
not been, except as indicated in any subsequently filed SEC Reports, any
change in the assets, liabilities, financial condition or operations of the 
company from that reflected in the Company 10-K for 1998, other than 
changes in the ordinary course of business, none of which individually or 
in the aggregate has had or is expected to have a material adverse effect 
on the Company.

SECTION 3.6      NO INTEGRATION.  Neither the Company nor any of its
affiliates, nor any person acting on its or their behalf, has, within the
six-month period prior to the date hereof, offered or sold or otherwise
disposed of any shares of its capital stock or instruments representing
interest in its capital stock, nor agreed to do any of the foregoing by
means of any form of general solicitation or advertising within the meaning
of Rule 502(c) under the Securities Act.

SECTION 3.7     NO BROKERS.  Except as set forth on the Disclosure Schedule,
no broker, finder or investment banker is entitled to any brokerage, finder
or other fee or commission in connection with the transactions contemplated
by this Agreement based on arrangements made by or on behalf of the Company.

SECTION 3.8     CAPITALIZATION.  The authorized capital stock of the Company 
immediately following the Closing is set forth on the Disclosure Schedule.

(a)     Other than that which is set forth on Disclosure Schedule there are
no other authorized or issued shares of capital stock of the Company.

(b)     Other than that which is set forth on the Disclosure Schedule there
are: (i) no outstanding warrants, options, agreements, convertible securities
or other commitments or instruments pursuant to which the Company is or may 
become obligated to issue, sell, repurchase or redeem any shares of capital 
stock or other securities of the Company, except pursuant to the Company's 
certificate of incorporation, this Agreement and the Warrant; (ii) no 
preemptive, contractual or similar rights to purchase or otherwise acquire 
shares of capital stock of the Company pursuant to any provision of law or 
any agreement to which the Company is a party, except pursuant to this 
Agreement and the Warrant; (iii) no restrictions on the transfer of capital 
stock of the Company imposed by any statute, other than those imposed by 
relevant state and federal securities laws, or any agreement to which the 
Company is a party, or any order of any court or any governmental agency to 
which the Company is subject; (iv) to the best of our knowledge and belief, 
no cumulative voting rights for any of the Company's capital stock; (v) no 
registration rights under the Securities Act, with respect to shares of the 
Company's capital stock, except pursuant to the Registration Agreement; 
(vi) to the best of the Company's knowledge and belief, no options or other 
rights to purchase shares of capital stock from stockholders of the Company 
granted by such stockholders, except pursuant to the Warrant; and (vii) no 
agreements, written or oral, between the Company and any holder of its 
securities, or, to the best of the Company's knowledge and belief, among 
holders of its securities, relating to

                               -4-
<PAGE>5

the acquisition, disposition or voting of the securities of the Company,
except pursuant to the Warrant and Registration Agreement.

SECTION 3.9     BUSINESS OF THE COMPANY.  Since 1990 each employee of or
consultant to the Company who has or is proposed to have access to 
confidential and/or proprietary information of the Company (other than the 
Company's legal counsel) is a signatory to, and is bound by, an agreement 
with the Company relating to nondisclosure, proprietary information and 
assignment of intellectual property rights.

SECTION 3.10    SECURITIES LAWS.  Neither the Company nor, to the best
knowledge of the Company, anyone acting on its behalf has offered securities
of the Company for sale to, or solicited any offers to buy the same from, or
sold securities of the Company to, any person or organization, in any case so
as to subject the Company, its promoters, directors and/or officers to any 
liability under the Securities Act, the Exchange Act, or any state 
securities or "blue sky" law (collectively, "Securities Laws").  The sale 
of the Shares will not violate any provision of the Securities Laws when 
offered, issued and sold in accordance with this Agreement or the Warrant.

                             ARTICLE 4

            REPRESENTATIONS AND WARRANTIES OF THE PURCHASER

       The Purchaser hereby represents and warrants to the Company as follows:

SECTION 4.1     PURCHASER'S ORGANIZATION, GOOD STANDING AND QUALIFICATION. The
Purchaser is a societe anonyme duly organized, validly existing and in 
good standing under the laws of France, and has all requisite corporate 
power and authority to own, operate and lease its properties and to carry 
on its business as presently conducted.  The Purchaser is duly qualified as 
a foreign corporation and is in good standing in each jurisdiction where 
the character of the property owned or leased by it or the nature of its 
activities makes such qualification necessary, except for those 
jurisdictions where the failure to do so would not, individually or in the 
aggregate, have a material adverse effect on the business or financial 
condition or operations of the Purchaser.

SECTION 4.2     PURCHASER'S POWER AND AUTHORITY.  The Purchaser has all
requisite power and authority to execute and deliver this Agreement and to
perform its obligations under such agreements and to consummate the
transactions contemplated hereby.  The execution, delivery and performance
by the Purchaser of this Agreement and the consummation by the Purchaser of
the transactions contemplated hereby have been duly authorized and approved
by the Purchaser's Board of Directors and no further action on the part of
the Purchaser or its stockholders is necessary to authorize the execution, 
delivery and performance of such agreements or the consummation by the 
Purchaser of the transactions contemplated hereby.  This Agreement has been 
duly executed and delivered by the Purchaser and constitutes the valid and 
binding obligation of the Purchaser, enforceable against the Purchaser in 
accordance with its terms, except as enforcement thereof (i) may be limited 
by bankruptcy, insolvency, reorganization, fraudulent conveyance, 
moratorium or other similar laws

                                    -5-
<PAGE>6

relating to or affecting enforcement of creditors' rights generally, or
(ii) is subject to general principles of equity (regardless of whether
enforcement is considered in a proceeding in equity or at law).

SECTION 4.3     NO CONFLICT; CONSENTS.

(a)     No Conflict.  The execution and delivery of this Agreement by the
Purchaser does not, and the performance of this Agreement and the consummation
of any of the transactions contemplated by this Agreement by the Purchaser will
not, directly or indirectly (with or without notice or lapse of time):

        (i)  contravene, conflict with or result in a violation of (A) any of
the provisions of the articles of incorporation or bylaws of the Purchaser, or
(B) any resolution adopted by the Purchaser's Board of Directors;

        (ii) contravene, conflict with or result in a violation of, any law,
rule, regulation or order binding upon the Purchaser or any of the properties
or assets owned or used by the Purchaser;

        (iii) contravene, conflict with or result in a violation of any of the
terms or requirements of, any governmental authorization that is held by the 
Purchaser or that otherwise relates to the business of, or any of the 
properties or assets owned or used by, the Purchaser;

        (iv)  result in the imposition or creation of any lien or other
encumbrance on or with respect to any property or asset owned or used by the
Purchaser.

(b)     Consents.  The execution and delivery of this Agreement do not, and
the performance of this Agreement and the consummation of the transactions 
contemplated hereby will not, require any filing with or the giving of any 
notice to, or the obtaining any consent from, any governmental authority.

SECTION 4.4     INVESTMENT REPRESENTATIONS.

(a) Representations.  The Purchaser understands that the Shares and Warrants
(and the shares of Common Stock issuable upon exercise of the Warrant) have 
not been, and will not be, registered under the Securities Act or any other 
securities law.  The Purchaser also understands that the Shares and 
Warrants are being offered and sold pursuant to an exemption from 
registration contained in Section 4(2) of the Securities Act as part of an 
issue not involving a public offering.  To confirm to the Company the basis 
of such an exemption, Purchaser hereby represents and warrants to the 
Company as follows:

        (i)  Purchaser Bears Economic Risk.  The Purchaser understands that it
must bear the economic risk of this investment indefinitely unless the Shares
and Warrants (and the shares of Common Stock underlying the Warrants) are 
registered pursuant to the Securities Act, or an exemption from 
registration is available.  Purchaser acknowledges that Company is a 
development stage company and has not operated profitably and there can be 
no assurance it will operate profitably.  Purchaser acknowledges that it is 
fully capable of bearing such economic risk.

                                  -6-
<PAGE>7

        (ii)  Acquisition for Own Account.  The Purchaser is acquiring the
Shares and Warrant for the Purchaser's own account for investment only, and
not with a view towards their distribution or resale.

        (iii) Purchaser Can Protect Its Interest.  The Purchaser represents
that by reason of its, or of its management's, business or financial experience,
the Purchaser has the capacity to protect its own interests in connection 
with the transactions contemplated in this Agreement.  Further, the 
Purchaser is aware of no publication of any advertisement in connection 
with the transactions contemplated in the Agreement.

        (iv)  Accredited Investor.  The Purchaser represents that it is an
"accredited investor" within the meaning of Regulation D under the Securities
Act.

        (v)  Company Information.  The Purchaser has requested, received,
reviewed and considered all the information that the Purchaser considers
necessary for making an informed decision to invest in the Shares and Warrant,
and that Purchaser has received or has access (on its own) to copies of the SEC
Reports, including (i) the Company's report on Form 10-K for 1998.  The 
Purchaser has also had an opportunity (i) to ask questions of and receive 
answers from the Company regarding the contemplated issuance of the Shares 
and Warrant, and the business, properties, prospects and financial 
condition of the Company, and (ii) to obtain such additional information 
(to the extent that the Company possessed such information or could acquire 
it without unreasonable effort or expense) necessary to verify the accuracy 
of any information furnished to the Purchaser or to which the Purchaser had 
access.

(b)     Rule 144.  Purchaser acknowledges and agrees that the Shares and
Warrants (and shares of Common Stock issuable upon exercise of the Warrant)
must be held indefinitely unless they are subsequently registered under the 
Securities Act or an exemption from such registration is available.  
Purchaser understands that except for its obligations under the 
Registration Agreement to be delivered under Article 6, the Company is 
under no obligation (A) to register the Shares or Warrant (or shares of 
Common Stock isusable upon exercise of the Warrant) under the Securities 
Act or any state securities act or (B) to comply with the requirements for 
any exemption which might otherwise be available thereunder.  Further, 
Purchaser acknowledges that except for its obligations under the 
Registration Agreement to be delivered under Article 6, the Company has 
made no agreement to register the Shares or Warrant (or shares of Common 
Stock issauble upon exercise of the Warrant) under such laws or to take 
action to provide for the future availability of any exemption thereunder.  
Purchaser has been advised or is aware of the provisions of Rule 144 
promulgated under the Securities Act as in effect from time to time, which 
permits limited resale of securities purchased in a private placement 
subject to the satisfaction of certain conditions including, among other 
things, the availability of certain current public information about the 
Company, the resale occurring following the required holding period under 
Rule 144 and the number of shares being sold during any three-month period 
not exceeding specified limitations.

                                 -7-
<PAGE>8

(c)     Legend.  Purchaser understands and agrees that stop-transfer
instructions may be noted on the appropriate records of Company, and that
there will be placed on the certificates for the Shares and on the Warrant, or
any substitutions therefor, a legend stating in substance:

        The securities evidenced by this certificate have not been
        registered under the Securities Act of 1933, as amended (the 
        "Securities Act"), in reliance upon the exemption from 
        registration under the Securities Act and have not been 
        registered under the securities laws of applicable states in 
        reliance upon applicable exemptions from registration under the 
        securities laws of such states.  These shares have been acquired 
        for investment purposes only and may not be offered, sold or 
        transferred, nor will any assignee or transferee thereof be 
        recognized by the Company as having any interest in these 
        shares, in the absence of (i) an effective registration 
        statement with respect to the shares under the Securities Act 
        and applicable state securities laws or (ii) compliance with 
        applicable exemptions from registration under the Securities Act 
        and applicable state securities laws.  The Company may, if it 
        deems appropriate in its sole discretion, require an opinion of 
        counsel satisfactory to the Company that the offer, sale or 
        transfer of these shares is exempt from registration under the 
        Securities Act and applicable state securities laws.

                               ARTICLE 5

                    CERTAIN COVENANTS OF THE COMPANY

SECTION 5.1     RULE 144.  If at any time the Company is not subject to
Section 13 or 15(d) of the Exchange Act, the Company shall cause to be made
publicly available the information concerning the Company specified in
paragraphs (a)(5)(i) to (xiv), inclusive, and (xvi) of Rule 15c2-11 under the
Exchange Act.

SECTION 5.2     PRESS RELEASES; DISCLOSURES. Neither the Company nor the
Purchaser shall, without the prior written consent of the other, issue any 
press release or make any other public announcement or furnish any 
statement to any person or entity (other than either party's respective 
Affiliates, as that term is defined under the Securities Act) concerning 
the existence of this Agreement and the transactions contemplated by this 
Agreement except for (i) general statements referring to the existence of 
this Agreement, specifying its nature (Common Stock and Warrant Purchase), 
the identity of the parties but no other details, (ii) disclosures made in 
compliance with Section 4.1 (a) of the Collaboration and Option Agreement, 
dated as of October 30, 1998, by and between the Company and the Purchaser 
(the "Collaboration Agreement") or under any license agreement entered into 
under the Collaboration Agreement, (iii) attorneys, consultants and 
accountants retained to represent them in connection with the transactions 
contemplated hereby or as may be reasonably necessary to either party's 
bankers, investors, attorneys or other professional advisers in connection 
with a merger or acquisition, provided such advisors are bound by 
confidentiality obligations essentially identical to those set forth in 
Section 4.1 of the Collaboration Agreement or any license agreement entered 
into under the Collaboration Agreement, and (iv) occasional brief comments 
by the respective executive officers of both parties consistent with such 
guidelines for public statements as may be mutually agreed by the parties 
made in connection with routine interviews with analysts or members

                                -8-
<PAGE>9

of the financial press.  In addition, either party (after consultation with
counsel) in its own right may make such further announcements and 
disclosures, if any, as may be required by applicable securities laws and 
regulations (such as, without limitation, regulations of the SEC or the 
French Commission des Operations de Bourse (COB), or any equivalent 
authority of any country having jurisdiction), in which case the party 
making the announcement or disclosure shall use its best efforts to give 
advance notice to and discuss such announcement or disclosure with the 
other party and such other party's attorneys.

                             ARTICLE 6

                        CLOSING DOCUMENTS

SECTION 6.1     COMPANY'S DOCUMENTS.  Simultaneously with the execution and
delivery of this Agreement, the Company has delivered a certificate of Seth 
I. Truwit, its corporate secretary, certifying as to (1): the Company's 
current Certificate of Incorporation, as amended, duly certified by the 
Secretary of State of the State of Delaware, and that the Company is duly 
incorporated, validly existing and in good standing under Delaware law, (2) 
the Company's current by-laws, as amended, (3) the resolution(s) adopted by 
the Board of Directors of the Company approving this Agreement, the 
issuance of the Shares and the Warrant and the transactions contemplated 
hereby and thereby, and (4) a legal opinion from Epstein Becker & Green, PC 
in a form reasonably satisfactory to the Purchaser.

SECTION 6.2     PURCHASER'S DOCUMENTS.  Simultaneously with the execution and
delivery of this Agreement, Purchaser has delivered to the Company a 
certificate of its corporate secretary, certifying as to (1): the Company's 
current Certificate of Incorporation, as amended, duly certified by the 
appropriate regulatory authority of France, (2) the Purchaser's current by-
laws, as amended, and (3) the power of attorney executed by the Chairman of 
the  Purchaser appointing certain individuals to execute this Agreement and 
the Registration Rights Agreement and the transactions contemplated hereby 
and thereby.

                             ARTICLE 7

                           MISCELLANEOUS

SECTION 7.1     FEES AND EXPENSES.  Each party to this Agreement shall bear and
pay all fees, costs and expenses (including legal fees and accounting fees) 
that have been incurred or that are incurred by such party in correction 
with the transactions contemplated by this Agreement, including all fees, 
costs and expenses incurred by such party in connection with or by virtue 
of (a) the investigation and review conducted by the Purchaser with respect 
to the Company's business (and the furnishing of information to the 
Purchaser in connection with such investigation and review), (b) the 
negotiation, preparation and review of this Agreement (including the 
Disclosure Schedule) and all agreements, certificates, opinions and other 
instruments and documents delivered or to be delivered in connection with 
the transactions contemplated by this Agreement, (c) the preparation and 
submission of any filing or notice required to be made or given in 
connection with any of the transactions contemplated by this

                                -9-
<PAGE>10

Agreement, and the obtaining of any consent required to be obtained in
connection with any of such transactions, and (d) the consummation of the
transactions contemplated by this Agreement.

SECTION 7.2     GOVERNING LAW.  This Agreement shall be governed in all
respects by the laws of the State of New York.

SECTION 7.3     SURVIVAL.  The representations, warranties, covenants and
agreements made herein shall survive any investigation made by the 
Purchaser and the closing of the transactions contemplated hereby for a 
period of two years from the date hereof, except those contained in Section 
5.1 shall survive until the Purchaser no longer holds any Shares and those 
contained in Section 5.2 shall survive until the Purchaser is no longer 
deemed, under Section 13(d) of the Exchange Act, to own beneficially more 
than 5% of the Common Stock of the Company.

SECTION 7.4     SUCCESSORS AND ASSIGNS.  Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and
be binding upon, the successors, assigns, heirs, executors and administrators
of the parties hereto and shall inure to the benefit of and be enforceable by
each person who shall be a holder of the Shares or Warrant (or shares of
Common Stock issuable upon exercise of the Warrant) from time to time.

SECTON 7.5      ENTIRE AGREEMENT.  This Agreement and the other documents
delivered pursuant hereto constitute the full and entire understanding and 
agreement between the parties with regard to the subjects hereof and no 
party shall be liable or bound to any other in any manner by any 
representations, warranties, covenants and agreements except as 
specifically set forth herein and therein.

SECTION 7.6     SEVERABILITY.  In the event that any provision of this
Agreement, or the application of any such provision to any person or entity
or set of circumstances, shall be determined to be invalid, unlawful, void or
unenforceable to any extent, the remainder of this Agreement, and the 
application of such provision to persons or entities or circumstances other 
than those as to which it is determined to be invalid, unlawful, void or 
unenforceable, shall not be impaired or otherwise affected and shall 
continue to be valid and enforceable to the fullest extent permitted by 
law.
                               -10-
<PAGE>11

SECTION 7.7     NOTICES.

(a)	All notices, requests, demands and other communications hereunder
shall be in writing and shall be either (i) delivered by hand, (ii) mailed 
by registered or certified mail, return receipt requested, (iii) sent by 
overnight courier service, or (iv) sent by facsimile (with a confirming 
copy delivered as specified in any of the preceding clauses (i), (ii) or 
(iii)), to the parties addressed as follows:

        If to Purchaser:
        ---------------
        Pasteur Merieux Serums & Vaccins, S.A.
        58, avenue Leclerc
        69007 Lyon, France
        Telecopy No:  011 33 4 72 73 77 84
        Attention:  Senior Vice President, Legal and Corporate Affairs

        with copies to:

        Pasteur Merieux Connaught - USA
        Route 611
        Swiftwater, PA  18370
        Telecopy No:  (717) 839-4600
        Attention:  Vice President, Business Development 

        and

        L. Kevin O'Mara, Jr., Esq.
        Akin, Gump, Strauss, Hauer & Feld, L.L.P.
        590 Madison Avenue
        New York, NY  10022
        Telecopy No:  (212) 872-1002


                               -11-
<PAGE>12

        If to the Company:
        -----------------

        Cistron Biotechnology, Inc. 
        10 Bloomfield Avenue 
        Pine Brook, NJ  07058
        Telecopy Number:  (973) 575-4054 
        Attention: President

        With a copy to:

        Seth I. Truwit, Esq.
        Epstein Becker & Green, PC 
        250 Park Avenue
        New York, NY  10177
        Telecopy Number:  (212) 661-0989 

(b)     All notices, requests, instructions or documents given to any 
party in accordance with this Section shall be deemed to have been given 
(i) on the date of receipt, if delivered by hand, sent by overnight courier 
service, or sent by facsimile or (ii) on the date which is seven business 
days after delivery to the United States Postal Service, if mailed in the 
manner prescribed above.  Any party hereto may change its address specified 
for notices herein by designating a new address for such notices by a notice 
given in accordance with this Section.

SECTION 7.8     REMEDIES CUMULATIVE; SPECIFIC PERFORMANCE.  The rights and
remedies of the parties hereto shall be cumulative (and not alternative).  
The parties to this Agreement agree that, in the event of any breach or 
threatened breach by any party to this Agreement of any covenant, 
obligation or other provision set forth in this Agreement for the benefit 
of any other party to this Agreement, such other party shall be entitled 
(in addition to any other remedy that may be available to it) to (a) a 
decree or order of specific performance or mandamus to enforce the 
observance and performance of such covenant, obligation or other provision, 
and (b) an injunction restraining such breach or threatened breach.

SECTION 7.9     WAIVER.  No failure on the part of any party to exercise any
power, right, privilege or remedy under this Agreement, and no delay on the 
part of any party in exercising any power, right, privilege or remedy under 
this Agreement, shall operate as a waiver of such power, right, privilege 
or remedy; and no single or partial exercise of any such power, right, 
privilege or remedy shall preclude any other or further exercise thereof or 
of any other power, right, privilege or remedy.  No party shall be deemed 
to have waived any claim arising out of this Agreement, or any power, 
right, privilege or remedy under this Agreement, unless the waiver of such 
claim, power, right, privilege or remedy is expressly set forth in a 
written instrument duly executed and delivered on behalf of such party; and 
any such waiver shall not be applicable or have any effect except in the 
specific instance in which it is given.

SECTION 7.10    AMENDMENTS.  This Agreement may not be amended, modified,
altered or supplemented other than by means of a written instrument duly
executed and delivered on behalf of all of the parties hereto.

                              -12-
<PAGE>13

SECTION 7.11    HEADINGS.  The headings contained in this Agreement are for
convenience of reference only and are not to be considered in construing 
this Agreement.

SECTION 7.12    COUNTERPARTS.  This Agreement may be executed in several
counterparts, each of which shall constitute an original and all of which, 
when taken together, shall constitute one agreement.

                          [SIGNATURES ON NEXT PAGE]

                                     -13-
<PAGE>14

IN WITNESS WHEREOF, the parties hereto have executed this COMMON STOCK AND
WARRANT PURCHASE AGREEMENT as of the date set forth in the first paragraph 
hereof.


COMPANY:                             PURCHASER:

CISTRON BIOTECHNOLOGY, INC.          PASTEUR MERIEUX SERUMS & VACCINS, S.A.



By: /s/BRUCE C. GALTON               By: /s/DAVID J. WILLIAMS
    ------------------                   ---------------------
Name: BRUCE C. GALTON                    Name: DAVID J. WILLIAMS
Title: Chairman of the Board             Title: President 
       and Chief Financial Officer              and Chief Operating Officer



                               -14-
<PAGE>15

Void after 5:00 P.M.                               Common Stock Warrant
New York Time                                      to Purchase 666,667 Shares 
October 29, 2001                                   of Common Stock of Cistron
                                                   Biotechnology, Inc.    

                                                          No. 3

                       CISTRON BIOTECHNOLOGY, INC.

                      Common Stock Purchase Warrant
                           __________________

                This Warrant is being issued pursuant to the 
        Common Stock and Warrant Purchase Agreement dated the 
        date hereof, between Cistron Biotechnology, Inc. and 
        the Holder and is issued subject to the terms of such 
        Common Stock and Warrant Purchase Agreement.  This 
        Warrant and the shares of Common Stock issuable upon 
        exercise of this Warrant have not been registered under 
        the Securities Act of 1933, as amended (the "Act"), and 
        may not be sold or otherwise disposed of except (a) to 
        a person who, in the opinion of counsel reasonably 
        acceptable to the Company, is a person to whom the 
        securities may be legally transferred without 
        registration and without delivery of a current 
        prospectus under the Act or (b) to a person upon 
        delivery of a prospectus or offering circular then 
        meeting the requirements of the Act relating to such 
        securities and the offering thereof for such sale or 
        disposition.
                           __________________


        This certifies that, FOR VALUE RECEIVED, PASTEUR MERIEUX SERUMS & 
VACCINS, S.A. or registered assigns (the "Holder"), is entitled to 
purchase, subject to the provisions of this Warrant, from CISTRON 
BIOTECHNOLOGY, INC., a Delaware corporation (the "Company"), 666,667 shares 
of the Company's common stock, $.01 par value (the "Common Stock"), at a 
price of $.25 per share at any time prior to 5:00 P.M., New York Time, on 
October 29, 2001, at which time this Warrant shall expire and become void.  
The number of shares of Common Stock to be received upon exercise of this 
Warrant and the price to be paid for each share of Common Stock are subject 
to possible adjustment from time to time as hereinafter set forth.  The 
shares of Common Stock or other securities or property deliverable upon 
such exercise as adjusted from time to time are hereinafter sometimes 
referred to as the "Warrant Shares" and the exercise price of a share of 
Common Stock in effect at any time and as adjusted from time to time is 
hereinafter sometimes referred to as the "Exercise Price."  Unless the 
context otherwise requires, the term "Warrant" as used herein includes this 
Warrant and any other warrant or warrants that may be issued pursuant to 
the provisions of this Warrant, whether upon transfer, assignment, partial 
exercise, divisions, combinations, exchange, or otherwise, and the term 
"Holder" includes any transferee or transferees or assignee or assignees of 
the Holder named above, all of whom shall be subject to the provisions of 
this Warrant, and, when used with reference to Warrant Shares, means the 
holder or holders of such Warrant Shares.

        Section 1.      Exercise of Warrant.
                        --------------------

                1.1.    Method of Exercise.  This Warrant may be exercised in
whole or in part, but for not less than 50,000 Warrant Shares or the 
balance then exercisable, at any time by the Holder prior to 5:00 P.M., New 
York Time, on October 29, 2001, by presentation and surrender hereof to the 
Company at its

                                 -15-
<PAGE>16

principal office with the Subscription Form annexed hereto, duly executed
and accompanied by payment, by certified or official bank checks payable to
the order of the Company, of the Exercise Price for the total number of
Warrant Shares purchased.

                1.2.    Delivery of Shares.  Upon proper exercise of this 
Warrant, the Company promptly shall deliver certificates for the Warrant 
Shares to the Holder duly legended as authorized in the Subscription Form.

                1.3.    Partial Exercise.  If this Warrant is exercised in 
part only, the Company shall, upon presentation of this Warrant upon such 
exercise, execute and deliver (with the certificate for the Warrant Shares 
purchased) a new Warrant evidencing the rights of the Holder hereof to 
purchase the balance of the Warrant Shares purchasable hereunder upon the 
same terms and conditions as herein set forth.

                1.4.  Fractional Shares.  No fractional shares or scrip 
representing fractional shares shall be issued upon exercise of this 
Warrant but, in lieu thereof, the Company shall round up to the next full 
share. 

        Section 2.      Exercise Price and Adjustments.
                        -------------------------------

                2.1.    The Exercise Price at which the Warrant Shares shall 
be purchasable shall be $.25 per share, subject to adjustment as follows:

                                (a) Stock Dividends.  If at any time after the
date of the issuance of this Warrant (i) the Company shall pay a stock 
dividend payable in shares of Common Stock or (ii) the number of shares of 
Common Stock shall have been increased by a subdivision or split-up of 
shares of Common Stock, then, on the date of the payment of such dividend 
or immediately after the effective date of subdivision or split-up, as the 
case may be, the number of shares to be delivered upon exercise of this 
Warrant will be increased so that the Holder will be entitled to receive 
the number of shares of Common Stock that such Holder would have owned 
immediately following such action had this Warrant been exercised 
immediately prior thereto, and the Exercise Price will be adjusted as 
provided below in paragraph (d).

                                (b) Combination of Common Stock. If the number
of shares of Common Stock outstanding at any time after the date of the 
issuance of this Warrant shall have been decreased by a combination of the 
outstanding shares of Common Stock, then,  immediately after the effective 
date of such combination, the number of shares of Common Stock to be 
delivered upon exercise of this Warrant will be decreased so that the 
Holder thereafter will be entitled to receive the number of shares of 
Common Stock that such Holder would have owned immediately following such 
action had this Warrant been exercised immediately prior thereto, and the 
Exercise Price will be adjusted as provided below in paragraph (d).

                                (c) Reorganization, etc.  If any capital 
reorganization of the Company, or any reclassification of the Common Stock, 
or any consolidation of the Company with or merger of the Company with or 
into any other person or any sale, lease or other transfer of all or 
substantially all of the assets of the Company to any other person, shall 
be effected in such a way that the holders of Common Stock shall be 
entitled to receive stock, other securities or assets (whether such stock, 
other securities or assets are issued or distributed by the Company or 
another person) with respect to or in exchange for Common Stock, then, upon 
exercise of this Warrant the Holder shall have the right to receive the 
kind and amount of stock, other securities or assets receivable upon such 
reorganization, reclassification, consolidation, merger or sale, lease or 
other transfer of all or substantially all the assets of the Company that 
such Holder would have been entitled to receive upon exercise of this 
Warrant had this Warrant been exercised immediately before such 
reorganization, reclassification, consolidation, merger or sale, lease or 
other transfer of all or substantially all the assets of the

                             -16-
<PAGE>17

Company, subject to adjustments that shall be as nearly equivalent as may be
practicable to the adjustments provided for in this Section 2.1.

                                (d) Exercise Price Adjustment.  Whenever the 
number  of Warrant Shares purchasable upon the exercise of the Warrant is 
adjusted as provided pursuant to this Section 2.1, the Exercise Price 
payable upon the exercise of this Warrant shall be adjusted by multiplying 
such Exercise Price immediately prior to such adjustment by a fraction, of 
which the numerator shall be the number of Warrant Shares purchasable upon 
the exercise of the Warrant immediately prior to such adjustment, and of 
which the denominator shall be the number of Warrant Shares purchasable 
immediately thereafter; provided that the Exercise Price for each Warrant 
Share shall in no event be less than the par value of such Warrant Share.

                2.2.    No Adjustment for Dividends.  Except as provided in 
Section 2.1, no adjustment in respect of any dividends shall be made during 
the term of this Warrant or upon the exercise of this Warrant.  
Notwithstanding any other provision hereof, no adjustments shall be made on 
Warrant Shares issuable on the exercise of this Warrant for any cash 
dividends paid or payable to holders of record of Common Stock prior to the 
date as of which the Holder shall be deemed to be the record holder of such 
Warrant Shares.

                2.3.    Notice of Adjustment.  Whenever the number of Warrant 
Shares or the Exercise Price of such Warrant Shares is adjusted, as herein 
provided, the Company shall promptly mail by first class, postage prepaid, 
to the Holder, notice of such adjustment or adjustments and a certificate 
of a firm of independent public accountants of recognized standing selected 
by the Board of Directors of the Company (who are the independent public 
accountants regularly employed by the Company) setting forth the number of 
Warrant Shares and the Exercise Price of such Warrant Shares after such 
adjustment, setting forth a brief statement of the facts requiring such 
adjustment and setting forth the computation by which such adjustment was 
made.

                2.4.    Amendments.  Any provision of this Warrant may be 
amended and the observance thereof waived only with the written consent of 
the company and the Holder.

                2.5.    Cashless Exercise.  On any date on which this Warrant 
is exercisable, in lieu of the payment of the Exercise Price, the Holder 
shall have the right (the "Cashless Exercise Right") (but not the 
obligation), to require the Company to convert this Warrant, in whole or in 
part, into Common Stock in accordance with Section 1, and to require the 
Company to deliver to the Holder (without payment by the Holder of any of 
the Exercise Price) and in accordance with Section 1 that amount of Common 
Stock, equal to the quotient obtained by dividing (x) the value of the 
Warrant at the time the Cashless Exercise Right is exercised (determined by 
subtracting the aggregate Exercise Price in effect immediately prior to the 
exercise of the Cashless Exercise Right from the aggregate Fair Market 
Value for the shares of Stock covered by the Warrant immediately prior to 
the exercise of the Cashless Exercise Right) by (y) the Fair Market Value 
of one share of Common Stock immediately prior to the exercise of the 
Cashless Exercise Right.

                             (a) The Cashless Exercise Right may be exercised
by the Holder by delivering the Warrant, with a duly executed Subscription 
Form with the conversion section completed, to the Company, exercising the 
Cashless Exercise Right and specifying the total percentage of this Warrant 
that will be exercised.

                             (b) Fair Market Value of one share of Common 
Stock as of a particular date shall mean the average of the closing bid and 
asked prices as they are reported on the principal exchange of the Common 
Stock for the twenty (20) trading days ending on the day preceding the date 
the Warrant is exercised.

                             -17-
<PAGE>18

        Section 3.      Exchange, Assignment, or Loss of Warrant.
                        -----------------------------------------

                3.1.    Exchange of Warrant.  This Warrant is exchangeable, 
without expense, at the option of the Holder, upon presentation and 
surrender hereof to the Company for other Warrants of different 
denominations entitling the Holder thereof to purchase in the aggregate the 
same number of Warrant Shares purchasable hereunder on the same terms and 
conditions as herein set forth.

                3.2.    Assignment of Warrant.  Subject to compliance with 
Section 4 hereof, this Warrant may be assigned by presentation and 
surrender to the Company at its principal office or at the office of its 
stock transfer agent, if any, with the Assignment Form annexed hereto duly 
executed accompanied by funds sufficient to pay any transfer tax.  Upon 
such presentation and surrender, the Company shall, without charge, execute 
and deliver a new Warrant in the name of the assignee named in the 
Assignment Form and shall promptly cancel this Warrant.

                3.3.    Loss or Mutilation of Warrant.  Upon receipt by the 
Company of evidence satisfactory to it of the loss, theft, destruction, or 
mutilation of this Warrant, and (in the case of loss, theft, or 
destruction) of reasonably satisfactory indemnification, and upon surrender 
and cancellation of this Warrant, if mutilated, the Company will execute 
and deliver a new Warrant of like tenor and date and any such lost, stolen, 
or destroyed Warrant shall thereupon become void.  Any such new Warrant 
executed and delivered shall constitute an additional contractual 
obligation on the part of the Company, whether or not this Warrant so lost, 
stolen, destroyed, or mutilated shall be at any time enforceable by anyone.

                3.4.    Ownership of Warrant.  The Company may deem and treat 
the person in whose name this Warrant is registered as the holder and owner 
hereof (notwithstanding any notations of ownership or writing hereon made 
by anyone other than the Company) for all purposes and shall not be 
affected  by any notice to the contrary.

        Section 4.      Compliance with Securities Act of 1933.
                        ---------------------------------------

                4.1.    Disposition of Warrant and/or Warrant Shares.  This 
Warrant and/or the Warrant Shares may not be sold or otherwise disposed of 
except as follows:

                        (a)  To a person who, in the opinion of counsel 
        reasonably satisfactory to the Company, is a person to whom this 
        Warrant or the Warrant Shares may legally be transferred without 
        registration and without the delivery of a current prospectus 
        under the Act with respect thereto and then only against receipt 
        of an agreement of such person to comply with the provisions of 
        this Section 4 with respect to any resale or other disposition of 
        such securities unless, in the opinion of counsel, such agreement 
        is not required; or

                        (b)  To any person upon delivery of a prospectus or 
        offering circular then meeting the requirements of the Act 
        relating to such securities and the offering thereof for such 
        sale or disposition.

                4.2.    Legending of Certificates.  Each certificate for 
Warrant Shares or for any other security issued or issuable upon exercise 
of this Warrant shall contain a legend on the face thereof, in form and 
substance satisfactory to counsel to the Company, setting forth the 
restrictions on transfer thereof contained in this Section 4.

                                  -18-
<PAGE>19

        Section 5.      Company Covenants.
                        ------------------

                5.1.    Reservation and Issuance of Warrant Shares.  The
Company hereby undertakes until expiration of this Warrant to reserve for 
issuance and/or delivery upon exercise of this Warrant, such number of 
shares of its Common Stock as shall be required for issuance and/or 
delivery upon exercise hereon in full and agrees that all Warrant Shares so 
issued and/or delivered will be validly issued, fully paid, and non-
assessable and further agrees to pay all taxes and charges that may be 
imposed upon such issuance and/or delivery.

                5.2.    Officer's Certificate.  In the event the Exercise 
Price shall be adjusted as required by Section 2 hereof, the Company shall 
mail to the Holder an officer's certificate setting forth the adjustments 
so required and including, in reasonable detail, the method of calculating 
the adjustments and the transaction requiring the adjustment.

                5.3.    Notices of Corporate Action.  So long this Warrant 
has not been exercised in full, in the event of

                             (a) any taking by the Company of a record of the 
holders of any class of securities for the purpose of determining the 
holders thereof who are entitled to receive any dividend or other 
distribution, or any right to subscribe for, purchase or otherwise acquire 
any shares of Common Stock of any class or any other securities or 
property, or to receive any other right,

                             (b) any capital reorganization of the Company, 
any reclassification or recapitalization of the capital stock of the 
Company or any consolidation or merger involving the Company and any other 
person or any transfer of all or substantially all the assets of the 
Company to any other person, or

                             (c) any voluntary or involuntary dissolution, 
liquidation or winding-up of the Company, the Company will mail to the 
Holder a notice specifying (i) the date or expected date on which any such 
record is to be taken for the purpose of such dividend, distribution or 
right and the amount and character of any such dividend, distribution or 
right and (ii) the date or expected date on which any such reorganization, 
reclassification, recapitalization, consolidation, merger, transfer, 
dissolution, liquidation or winding-up is to take place and the time, if 
any such time is to be fixed, as of which the holders of record of Common 
Stock (or other securities) shall be entitled to exchange their shares of 
Common Stock (or other securities) for the securities or other property 
deliverable upon such reorganization, reclassification, recapitalization, 
consolidation, merger, transfer, dissolution, liquidation or winding-up.  
Such notice shall be delivered at least 10 days prior to the date therein 
specified, in the case of any date referred to in the foregoing 
subdivisions (i) and (ii).

        Section 6.      Miscellaneous.
                        --------------

                6.1.    Status of Holder.  The Holder shall not be entitled 
to vote or receive dividends and shall not otherwise be deemed a 
shareholder of the Company.

                6.2.    Notices.  All notices required hereunder shall be 
sent by first-class mail, postage prepaid, and shall be addressed, if to 
the Holder, to the last known address furnished to the Company and if to 
the Company, to: Cistron Biotechnology, Inc., 10 Bloomfield Avenue, Pine 
Brook, New Jersey  07058, Attn: Bruce Galton, Chairman and Chief Executive 
Officer, unless another address is designated in writing by the Holder of 
the Company.

                               -19-
<PAGE>20
                6.3.    Binding Effect.  This Warrant shall be binding upon 
the Company, its successors, and/or assigns and upon the Holder.

                6.4.    Governing Law.  The validity, interpretation and 
performance of this Warrant shall be governed by the laws of the State of 
New York.

                6.5.    No Rights or Liabilities as Common Stockholder.  
Nothing contained in this Warrant shall be determined as conferring upon 
the Holder any rights as a stockholder of the Company or as imposing any 
liabilities on the Holder to purchase any securities whether such 
liabilities are asserted by the Company or by creditors or stockholders of 
the Company or otherwise.

		IN WITNESS WHEREOF, this Warrant has been duly executed by the 
Company under its corporate seal as of this 30th day of October 1998. 



                                            CISTRON BIOTECHNOLOGY, INC.  


                                            By:/s/BRUCE C. GALTON
                                               ------------------
                                            Name: BRUCE C. GALTON
                                            Title: Chairman of the Board
                                                   and Chief Executive Officer


ATTEST:

/s/ SETH I. TRUWIT, ESQ.
------------------------
Name: SETH I. TRUWIT, ESQ.

                              -20-
<PAGE>21

FORM OF ASSIGNMENT

                        (To be signed only upon such assignment)



		FOR VALUE RECEIVED, the undersigned hereby sells, 
assigns and transfers unto 
the right represented by the within Warrant to purchase, from 
CISTRON BIOTECHNOLOGY, INC. (the "Company"), shares of the Common 
Stock of the Company, to which the within Warrant relates, and 
appoints

attorney to transfer said right, with full power of substitution 
in the premises.

Dated:

							
                                         ______________________________
                                        (Signature must conform in all
                                         respects to name of holder as
                                         specified on the face of the 
                                         Warrant)                    


ATTEST:


_____________________________
Name:

                                -21-
<PAGE>22

FORM OF SUBSCRIPTION

                        (To be signed only upon exercise of Warrant)



To:	CISTRON BIOTECHNOLOGY, INC.



		The undersigned, the holder of the within Warrant, hereby 
irrevocably elects to exercise the purchase rights represented by said 
Warrant for, and to purchase thereunder,      shares of Common Stock of the 
Company, and herewith makes payment of $               therefor, consents 
to the affixation of a legend on the certificate for such shares to the 
effect that such shares have not been registered under the Securities Act 
of 1933, as amended (the "Act"), and may be transferred only in compliance 
with the Act, and requests that such certificate(s) be issued in the name 
of and be delivered to

whose address is
and if such shares shall not be all of the shares purchased hereunder, that 
a new Warrant of like tenor for the balance of shares purchasable hereunder 
be delivered to the undersigned.

                Cashless Exercise Price Conversion Section

	By checking the following box the undersigned hereby irrevocably 
elects to exercise the Cashless Exercise Right in accordance with Section 2.5.


Dated:                                     _________________________________
                                           (Signature must conform in all
                                            respects to name of holder as
                                            specified on the face of the
                                            Warrant)

                                 -22-