PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST THE O-5 ANTIGEN OF SALMONELLA-TYPHIMURIUM LIPOPOLYSACCHARIDE

Three murine monoclonal antibodies (MAbs) were produced by fusion of P 3X63-Ag8.653 myeloma cells and splenocytes of a mouse immunized with h eat-attenuated (20 min, 80 degrees C) Salmonella typhimurium cells, MA bs 5A5 and 5B2 were of the immunoglobulin M (IgM) class, while MAb 4A8 was IgG2a, All possessed the kappa light chains, The MAbs were specif ic to the lipopolysaccharide (LPS) O-5 antigen of Salmonella B serogro up, as determined by electrophoresis followed by immunoblotting, All M Abs recognized the same epitope, as determined by an additive enzyme-l inked immunosorbent assay (ELISA), although IgM MAbs exhibited higher avidity than the IgG MAb, ELISA analyses revealed that all three MAbs reacted with S. typhimurium (LPS O:1, 4, 5, and 12) while failing to r ecognize S. typhimurium var, copenhagen (LPS O:1, 4, and 12). The MAbs reacted equally with live and heat-attenuated Salmonella B serovars c ontaining LPS O-5 antigen. The ability of the MAbs to detect live bact erial cells was further confirmed by transmission electron microscopy. Treatment of bacteria with cholic acid and extremely low pH did not a ffect antibody binding to S. typhimurium. However, when S. typhimurium tells were exposed to alkaline conditions prior to reaction with all three MAbs, no binding was observed, The use of MAbs to discriminate b etween S. typhimurium and S. typhimurium var. copenhagen in meat sampl es was investigated.