title: Isolation and characterization of murine monoclonal antibodies specific for gram-negative bacterial lipopolysaccharide: association of cross-genus reactivity with lipid A specificity.
abstract: Somatic cell hybrids secreting monoclonal antibodies against the core-glycolipid portion of enterobacterial endotoxin were derived from mice immunized with Escherichia coli J5 or Salmonella minnesota R595 heat-killed organisms or lipopolysaccharide (LPS). Eight antibodies were selected for their ability to cross-react with several members of a panel of gram-negative bacterial antigens in a radioimmunoassay. This panel represented five genera and two families of organisms: E. coli O111:B4, E. coli O55:B5, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella minnesota, and Serratia marcescens. The binding sites for six of the antibodies were unequivocally localized within the lipid A moiety of the endotoxin molecule by using the radioimmunoassay on LPS and free lipid A. The anti-lipid A antibodies were further characterized for their ability to interact with LPS variants by using a sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunostaining procedure. The monoclonal antibodies bound almost exclusively to the low-molecular-weight species of LPS on the polyacrylamide gel. These components corresponded to LPS isolated from rough strains of organisms (strains which lack O-specific carbohydrate). These results suggested that the cross-reactive component of antisera raised against rough mutants of gram-negative bacteria contain antibodies of lipid A specificity. Moreover, the determinant within the lipid A moiety of LPS may have been accessible to the monoclonal antibodies only in those endotoxin molecules on the outer membrane surface which lack the O-specific carbohydrate.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D006090:Gram-Negative Bacteria / Q000276:immunology*; D006825:Hybridomas; D007163:Immunosorbent Techniques; D007711:Klebsiella pneumoniae / Q000276:immunology; D008050:Lipid A / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D011863:Radioimmunoassay; D012475:Salmonella / Q000276:immunology; D012486:Salmonella typhimurium / Q000276:immunology; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D008050:Lipid A