CHARACTERIZATION OF MURINE ANTIBODY-RESPONSE TO SALMONELLA-TYPHIMURIUM BY A CLASS-SPECIFIC SOLID-PHASE RADIOIMMUNOASSAY

An H chain class-specific, solid phase radioimmunoassay was developed to characterize the murine antibody response to S. typhimurium. The specificity of the assay was verified by quantitation of the extent of binding of anti-S. typhimurium antibodies to other bacterial genera and species and by cross-adsorption studies. The sensitivity of the procedure was also examined, and it was substantially more sensitive than either the passive hemagglutination or the whole-cell agglutination technique. The method was subsequently used to analyze the murine antibody response to S. typhimurum. Groups of mice were prebled and then immunized with live S. typhimurium via different routes. The animals were bled weekly for 12 wk, and then were assayed for antibodies directed against whole bacteria or purified lipopolysaccharide. Anti-Salmonella antibodies of the IGM class appeared in the serum approximately 2-3 wk after immunization, and then IgG anti-Salmonella antibodies appeared which constituted the serum antibody response. The antibodies were primarily directed against the lipoplysaccharide determinants, but a small percentage of the response was directed against other cell surface components. Qualitatively and quatitatively similar anti-Salmonella antibody responses were observed in sera of outbred and inbred strains of mice.