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Anti-ampicillin monoclonal antibodies and their cross-reactivities to various beta-lactams
N Nagakura1, S Souma, T Shimizu
1Department of Microbiology, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Two cell lines producing monoclonal antibodies, Abp4 (IgM) and Abp7 (IgG1) against ampicillin were established. The epitopes and the cross-reactions of the antibodies with various beta-lactams were examined by enzyme-linked immunosorbent assay (ELISA) and ELISA inhibition test. Abp4 showed broad cross-reaction to human serum albumin (HSA) conjugates of several beta-lactams, 6-aminopenicillanic acid and 7-aminocephalosporanic acid. Abp7 reacted only with ampicillin and cephalexin, which have the same acyl side chain. In ELISA inhibition tests, Abp4 inhibited binding to ampicillin-HSA by benzylpenicilloyl-epsilon-amino-n-caproic acid, and strongly inhibited the binding by penicillamine. Abp7 strongly inhibited the reaction by aminobenzylpenicilloyl-epsilon-amino-n-caproic acid, but benzylpenicilloyl-epsilon-amino-n-caproic acid was less effected. These data suggest that Abp4 recognizes the thiazolidine ring and Abp7 recognizes the acyl side chain. Therefore, the thiazolidine ring-epitope acts in broad cross-reaction among beta-lactams, and the acyl side chain acts only in the cross-reactivity between penam and cephem, which have a similar acyl side chain.
Two cell lines producing monoclonal antibodies, Abp4 (IgM) and Abp7 (IgG1) against ampicillin were established. The epitopes and the cross-reactions of the antibodies with various beta-lactams were examined by enzyme-linked immunosorbent assay (ELISA) and ELISA inhibition test. Abp4 showed broad cross-reaction to human serum albumin (HSA) conjugates of several beta-lactams, 6-aminopenicillanic acid and 7-aminocephalosporanic acid. Abp7 reacted only with ampicillin and cephalexin, which have the same acyl side chain. In ELISA inhibition tests, Abp4 inhibited binding to ampicillin-HSA by benzylpenicilloyl-epsilon-amino-n-caproic acid, and strongly inhibited the binding by penicillamine. Abp7 strongly inhibited the reaction by aminobenzylpenicilloyl-epsilon-amino-n-caproic acid, but benzylpenicilloyl-epsilon-amino-n-caproic acid was less effected. These data suggest that Abp4 recognizes the thiazolidine ring and Abp7 recognizes the acyl side chain. Therefore, the thiazolidine ring-epitope acts in broad cross-reaction among beta-lactams, and the acyl side chain acts only in the cross-reactivity between penam and cephem, which have a similar acyl side chain.