César Milstein CH. 8 October 1927 – 24 March 2002

César Milstein was a scientist of the greatest distinction who made seminal contributions to our knowledge and understanding of antibodies. He advanced our knowledge of their structure, their expression, the generation of antibody diversity and the maturation of antibody affinity that occurs during the course of an immune response. Most spectacular was his discovery (jointly with Georges Köhler) of a method for obtaining monoclonal antibodies of predefined antigen specificity by fusing a continuously growing mouse myeloma cell line with a normal lymphocyte making monospecific antibody. For this, Milstein and Köhler received the Nobel Prize for Physiology or Medicine in 1984. Although this discovery was the product of a purely academic project, its impact on medicine and technology as well as in fundamental research has been enormous, opening new avenues in diagnostics and therapy. César Milstein remained an enthusiastic, creative and passionate scientist throughout his life.

Comparison of Dose Regimens for the Administration of Recombinant Pro-urokinase in a Canine Thrombosis Model

SummaryPro-urokinase represents an important addition to the array of thrombolytic drugs currently available for clinical use because of its high clot specificity but distinctly different mechanism compared with that of t-PA. Recombinant pro-urokinase (r-proUK) is a single-chain precursor of high molecular weight urokinase which has been expressed in a mouse myeloma cell line. The present study was conducted to determine the dosing regimen which would produce optimal clot lysis and restoration of blood flow 2 h after treatment with r-proUK, using a dog model of arterial thrombosis. Efficacy was indicated by lysis of a radiolabelled clot which was formed in the heat-damaged femoral arteries of 39 male beagle dogs. The animals were divided into six heparinized treatment groups, each receiving one of five dosing regimens or the vehicle for r-proUK. The total dose (80,000 U/kg) was divided into an initial loading bolus, followed by either a second bolus or by infusions for various time periods, as shown below:It was concluded that optimal clot lysis and restoration of femoral flow was accomplished using a regimen in which 50% of the dose was given as a bolus, followed immediately by the remaining 50% given as a 30 min intravenous infusion (Group 5). At the dose used in this study, r-proUK did not produce degradation of fibrinolytic or hemostatic plasma proteins.

Production and Characterization of Monoclonal Antibodies To Detect Vibrio cholerae Serogroup O1 in a Rapid Enzyme-Linked Immunosorbent Assay

Monoclonal antibodies (MAbs) were developed for a rapid and efficient screening procedure to detect cultures of Vibrio cholerae serogroup O1. Spleen cells of BALB/c mice previously immunized with an attenuated control strain of V. cholerae were fused with mouse myeloma cell line SP2/0. An enzyme-linked immunosorbent assay (ELISA) was used to test cultural hybridoma secretions of two MAbs against 120 strains of V. cholerae O1, 38 strains of V. cholerae non-O1, 15 strains of other Vibrio spp., and 20 strains of other bacterial species. Results of tests using both MAbs were identical. The MAbs successfully detected all of the confirmed serotype O1 strains. Three additional V. cholerae strains that agglutinated antisera and the saline control were considered serologically inconclusive. Of these, one was detected as positive for V. cholerae by both MAbs. The MAbs gave no false-positive reactions when tested against the confirmed non-O1 strains, other Vibrio spp., and other bacterial species. Use of this ELISA will enhance the speed and accuracy needed for detecting V. cholerae O1 cultures.

Production of Monoclonal Antibodies Specific to Clostridium botulinum Type B Neurotoxin

Four monoclonal antibodies were produced for use in a rapid method to detect Clostridium botulinum type B neurotoxin. Cells of mouse myeloma cell line SP2/0 were fused with splenocytes of immunized BALB/c mice. An immunoblot assay of semipurified commercial neurotoxins of C. botulinum types A, B, C, D, E, and F was used to show specificity. All the monoclonal antibodies reacted with type B neurotoxin but did not cross-react with the other types. The monoclonal antibodies, separately and combined, did not neutralize the toxin in mice, and all showed specificity to the whole neurotoxin molecule and the heavy-chain component by immunoblot. No evidence of specific binding to the hemagglutinin molecule was noted. When tested against concentrated cultured supernatants of C. botulinum types A, B, E, and F, the 4 monoclonal antibodies reacted only against type B strains. They will be incorporated into a rapid assay with other specific monoclonal antibodies to detect C. botulinum neurotoxins from pure cultures or suspect foods.