<PAGE>1

                        License Agreement
                        -----------------

This agreement is entered into and effective as of the 16th day of 
February, 1999 by and between R&D Systems, Inc., a Minnesota 
corporation with principal offices at 614 McKinley Place N.E., 
Minneapolis, MN 55413 [RDS], and Cistron Biotechnology Inc., a New 
Jersey Corporation with principal offices at 10 Bloomfield Avenue, 
Pine Brook, NJ 07058 [CBI].

1.      Recitals

        1.1.    Whereas CBI has an exclusive, worldwide license from the
                New England Medical Center Hospitals, Inc., Tufts 
                University, Massachusetts Institute of Technology, and 
                Wellesley College [the INSTITUTIONS] to make, use, sell, 
                and to sublicense to others, products utilizing human 
                interleukin 1 beta [IL-1B], which is the subject of 
                patents owned by the INSTITUTIONS, as set forth in 
                Schedule A.

        1.2.    Whereas CBI has patents which describe the production and 
                use of antibodies to IL-1B and immunoassays selective 
                for IL-1B,as set forth in Schedule A.

        1.3.    Whereas CBI has been granted license from Merck, & Co.
                Inc. for the research use of Interleukin 1 beta 
                converting enzyme [ICE],

        1.4.    Whereas RDS wishes to obtain assignment of the ICE
                LICENSE defined herein,

        1.5.    Whereas RDS wishes to obtain an exclusive sub-license to
                the INTELLECTUAL PROPERTY defined herein for the purpose 
                of commercializing products for the research market 
                worldwide, and CBI is willing to grant RDS such license 
                under the terms defined herein, and

        1.6.    In consideration of the mutual promises and undertakings
                of the parties as herein set forth, it is hereby agreed 
                as follows:

2.      Definitions

        2.1.    INTELLECTUAL PROPERTY means the licenses, United States
                and foreign patents and patent applications and any 
                divisions, continuations, continuations in part, 
                reissues, reexaminations, renewals, and extensions 
                thereof, and all pending applications therefor (a) are 
                described in paragraphs 1.1, and 1.2 and (b) are set 
                forth in Schedule A.

        2.2.    ICE LICENSE means the license granted to CBI by Merck &
                Co. Inc.

        2.3.    LICENSED PRODUCT(S) means any product(s) that contain(s)
                or is made employing the INTELLECTUAL PROPERTY. LICENSED 
                PRODUCTS shall include:

                2.3.1.  REAGENT(S) means any stand-alone product(s),
                        e.g., proteins or antibodies, that contain(s) or is 
                        made employing the INTELLECTUAL PROPERTY.

<PAGE>2

                2.3.2.  COMBINATION PRODUCT(S) means any product(s) 
                        that contain(s) more than a single reagent, e.g., 
                        immunoassays or matched reagents for immunoassays, 
                        where at least one of the components of this 
                        product contain(s) or is a REAGENT or is made 
                        employing the INTELLECTUAL PROPERTY.

        2.4.    NET SALES means the invoiced amount of sales of the
                LICENSED PRODUCT(S) by RDS to third parties less the 
                following items: (a) Customary trade, quantity and cash 
                discounts, sales rebates allowed and taken; (b) Credits 
                actually given for rejected or returned products; (c) 
                Freight and insurance if separately itemized on the 
                invoice and paid by the customer; and (d) Value-added, 
                sales, use or turnover taxes, excise taxes and customs 
                duties included in the invoice amount.

        2.5.    AFFILIATES means any organization controlling,
                controlled by, or under the common control with RDS. For 
                this purpose the term control means ownership, directly 
                or indirectly, of at least fifty percent (50%) of the 
                equity capital or a right to at least fifty- percent 
                (50%) of the profits.

        2.6.    FIELD means the research market.

        2.7.    TERRITORY means countries where patent protection exists.

3.      Grant and Assignment

        3.1.    CBI grants to RDS, including its AFFILIATES, and RDS
                accepts an exclusive, sub-license to make, have made, 
                use, sell, and sub-license the INTELLECTUAL PROPERTY in 
                the FIELD in the TERRITORY.

                3.1.1.  RDS shall use reasonable efforts to market 
                        LICENSED PRODUCTS in the FIELD and will manufacture 
                        its LICENSED PRODUCTS within the United States

        3.2.    CBI will seek assignment of the ICE LICENSE to RDS.

        3.3.    CBI will provide to RDS its customer list and sales 
                history for the past two (2) fiscal years.

        3.4.    CBI will cease its business as a provider of research 
                products relating to the INTELLECTUAL PROPERTY and ICE 
                LICENSE as defined herein.

        3.5.    CBI may continue to produce REAGENTS and COMBINATiON 
                PRODUCTS, using the INTELLECTUAL PROPERTY, for its own 
                research use and may also provide REAGENTS and/or 
                COMBINATION PRODUCTS to their collaborators, at no 
                charge, for use in CBI-sponsored research directed 
                toward the development of applications of the 
                INTELLECTUAL PROPERTY outside of the FIELD.

        3.6.    Should CBI dissolve, file for bankruptcy, has filed 
                against it an involuntary petition of bankruptcy which 
                is not dismissed within thirty (30) days after the date 
                of filing, or otherwise cease to actively conduct its 
                business, all rights to the INTELLECTUAL PROPERTY for 
                use in the FIELD in the TERRITORY shall be assigned to RDS.

<PAGE>3

4.      Payments, Reports, and Accounting

        4.1.    RDS agrees to pay CBI a one-time license initiation fee 
                of seven hundred fifty thousand dollars (US $750,000) 
                for the INTELLECTUAL PROPERTY within thirty (30) days of 
                the full execution of this Agreement.

        4.2.    RDS agrees to pay CBI a royalty equal to four percent 
                (4%) of NET SALES of REAGENT(S) and eight percent (8%) 
                of NET SALES of COMBINATION PRODUCT(S) in the TERRITORY.
    
        4.3.    RDS agrees to share equally any fees or royalties with 
                CBI derived from RDS sub-licensing activities of the 
                INTELLECTUAL PROPERTY.

        4.4.    CBI agrees to share equally any fees or royalties, net 
                of contractually defined payments made to the 
                INSTITUTIONS, with RDS derived from CBI's license 
                agreement with Peprotech Inc. (located at 5 Crescent 
                Avenue, Rocky Hill, New Jersey 08553).

        4.5.    RDS shall submit semi-annual written reports and royalty 
                payments, due within sixty (60) days following December 
                31 and June 30 of each year. This report shall include 
                the number, description, and aggregate NET SALES of 
                LICENSED PRODUCT(S) made during the reporting period, 
                and the resulting calculation of the royalty due. 
                Concurrent with the report, RDS shall include the 
                payment due to CBI of royalties for the period covered 
                by the report. All royalty payments shall be paid in US 
                Dollars.

        4.6.    RDS agrees to keep records for a period of three (3) 
                years showing the manufacture, sales, use, and other 
                disposition of the LICENSED PRODUCT(S) under the license 
                granted herein in sufficient detail to enable royalties 
                payable hereunder by RDS to be determined.

        4.7.    RDS further agrees to permit its books and records to be 
                examined by CBI to the extent necessary to verify 
                reports provided for in paragraph 4.5. Such examination 
                is to be made by CBI, at CBI's expense, and shall be on 
                a confidential basis no more frequently than once yearly.

5.	Representations

        5.1.    Each party represents to the other party that to the
                best of its knowledge it has full right and authority to 
                enter into this Agreement without the consent or 
                approval of any third party.

        5.2.    CBI represents and warrants that it is the owner of the 
                INTELLECTUAL PROPERTY and is unaware of any liens, 
                encumbrances, restrictions or other legal claims, to the 
                best of its knowledge and belief without having done any 
                due diligence.

        5.3.    CBI makes no representations and extends no warranties 
                of any kind, either express or implied. There are no 
                express or implied warranties of merchantability or 
                fitness for a particular purpose, or that the use of the 
                INTELLECTUAL PROPERTY will or does not infringe any 
                patent, trademark, or copyright of third parties.

<PAGE>4

6.      Patent Maintenance, Infringement and Enforcement

        6.1.    CBI will maintain any and all patents included hereinand 
                set forth in Schedule A, including but not exclusive of 
                maintenance fees and filings.

        6.2.    RDS shall have the right, at its discretion and its 
                expense, to enforce its patent rights granted herein.

                6.2.1.  Recoveries, damage awards or settlements, net 
                        of reimbursement of all expenses incurred by RDS to 
                        enforce the patent rights, shall be considered NET 
                        SALES when received by RDS and such net amounts 
                        shall be included in the determination of royalties 
                        due CBI.

        6.3.    CBI shall make available, at RDS' expense, any records 
                or documents that may be needed for any legal proceedings.

7.	Indemnification

        7.1.    RDS will indemnify, defend, and hold harmless CBl from
                any and all damages, costs, expenses, suits, claims and 
                judgments (including reasonable attorney's fees and 
                cost) arising from the conduct of RDS or its officers or 
                employees or arising from the production or use of the 
                INTELLECTUAL PROPERTY or the production, use or sale of 
                LICENSED PRODUCT(S) by RDS, except for any claims, 
                liability, damage, loss, cost, or expense caused by 
                CBI's negligence or willful misconduct in connection 
                with its supply of the INTELLECTUAL PROPERTY to RDS.

8.	Amendments

        8.1.    The Agreement constitutes the entire understanding
                between the parties with respect to the subject matter 
                herein, and no modification or amendment shall be valid 
                or binding upon the parties unless made in writing and 
                duly executed on behalf of each party.

9.	Confidentiality

        9.1.    All information submitted by one party to the other
                concerning the INTELLECTUAL PROPERTY and designated in 
                writing, shall be considered as confidential information 
                and shall be utilized only pursuant to the license 
                granted hereunder. During the term of this Agreement and 
                a period of five (5) years thereafter, neither party 
                shall disclose to any third party any information 
                received from the other party without the specific 
                written consent of that party. The foregoing shall not 
                apply where such information (a) was or becomes public 
                through no fault of the receiving party, (b) was at the 
                time of receipt, already in the possession of the 
                receiving party as evidenced by its written records, or 
                (c) was obtained from a third party legally entitled to 
                use and disclose the same.

10.	Term and termination

        10.1.   Unless earlier terminated pursuant to paragraph 10.2 the
                provisions of this Agreement will expire upon
                the expiration of the last of the INTELLECTUAL PROPERTY.

<PAGE>5

        10.2.   CBI may terminate this Agreement if RDS is in 
                default in payment of royalty or providing reports 
                provided that RDS fails to remedy any such default, 
                breach or false report within thirty (30) days of 
                written notice thereof by CBI.

        10.3.   Surviving any termination are (a) the obligation of 
                RDS to pay royalties accrued or accruable, (b) any cause 
                of action or claim of RDS or CBI, accrued or to accrue, 
                because of any breach or default by the other party, and 
                (c) the provisions of paragraphs 4, 7, and 9.
        
        10.4.   Upon termination by either party, RDS shall have 
                the right for one (1) year to dispose of all LICENSED 
                PRODUCT(S) then on hand or in process of manufacture, 
                and to complete all orders for such LICENSED PRODUCT(S) 
                then on hand or in process of manufacture, and royalties 
                shall be paid to CBI with respect to such LICENSED 
                PRODUCT(S) as though this Agreement had not terminated.

        10.5.   Upon termination by either party, any Agreement by 
                RDS granting sub-licensee rights shall be assigned to 
                CBI for the term of those agreements.

11.	Miscellaneous Provisions

        11.1.   Any notice or other communication required or
                permitted under this Agreement shall be in writing and 
                shall be deemed to have been given, when received, if 
                personally delivered or delivered by telegram, telex, or 
                facsimile, or when deposited, if placed in the US Mails 
                for delivery by registered or certified mail, return 
                receipt requested, postage prepaid and addressed to the 
                appropriate party at the address set forth below:

                To RDS: President
                        R&D Systems, Inc.
                        614 McKinley Place, N.E.
                        Minneapolis, MN 55413

                To CBI: President
                        Cistron Biotechnology Inc.
                        P.O. Box 2004
                        10 Bloomfield Avenue
                        Pine Brook, NJ 07058

        11.2.   This Agreement constitutes the entire agreement of 
                the parties with respect to the subject matter described 
                in this Agreement and shall supersede all previous 
                negotiations, commitments, writings, or agreements with 
                respect to such subject matter, including the License 
                and Supply Agreement between the parties effective as of 
                March 21, 1995 and the Research and Development 
                Agreement between the parties effect as of April 10, 1995.

        11.3.   This Agreement may not be released, discharged, 
                abandoned, changed, or modified in any manner, except by 
                an instrument in writing signed on behalf of both 
                parties to this Agreement by their duly authorized 
                representatives. The failure of either party to enforce 
                at any time any of the provisions of this Agreement 
                shall in no way be construed to be a waiver of any such
                provision, nor in any way to effect the validity of this 
                Agreement or any part of it or the right of either party 
                after any such failure to enforce each and every such 
                provision. No waiver of any breach of this Agreement 
                shall be held to be a waiver of any other or subsequent 
                breach.

<PAGE>6

        11.4.   This agreement shall be governed by, and construed 
                in accordance with the law of the State of Minnesota 
                (other than its law with respect to conflicts of laws), 
                including all matters of construction, validity, and 
                performance.

        11.5.   This Agreement shall be binding upon and inure to 
                the benefit of the parties to this Agreement and their 
                successors or assigns, provided that, except as 
                otherwise noted, the rights and obligations of either 
                party under this Agreement may not be assigned without 
                the written consent of the other party. Such consent 
                will not be unreasonable withheld.

        11.6.   The validity of any portion of this Agreement shall 
                not affect the validity, force or effect of the 
                remaining portions of this Agreement.
        
<PAGE>7

In witness whereof, the parties have caused this Agreement to be executed in
the manner appropriate for each.


Research and Diagnostic Systems Inc.

By /s/ THOMAS E. OLAND
  --------------------
  Thomas E. Oland, President


Date Feb. 18, 1999
     -------------

Cistron Biotechnology, Inc


By /s/ BRUCE C. GALTON
   -------------------
   Bruce C. Galton, President

Date 2-17-99
     -------

<PAGE>8
                           SCHEDULE A
                           ----------
                         IL-1B PATENTS