Characterization of human antibodies to Salmonella typhi by gel-filtration and antigenic analysis

A normal adult human male was immunized with a heat-killed typhoid vaccine. The appearance of antibodies to `H'' and `O'' antigens was subsequently studied. Antibodies were identified as belonging to specific immunoglobulin classes by gel-filtration on G-200 `Sephadex'', followed by specific immunochemical identification using a two-stage agglutination test. Serum antibodies to `H'' antigen were initially of γ_1M class; later the 7S γ class became predominant. γ_1A antibodies were transient in appearance. Serum antibodies to `O'' antigen were of γ<sub>1M</sub> and γ<sub>1A</sub> classes. Urinary antibodies to `H'' antigen were of γ_1A and 7S γ classes. No antibody activity could be detected in the low molecular weight γ-globulins of urine.