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 γ1M class; later the 7S γ class became predominant. γ1A antibodies were transient in appearance. Serum antibodies to `O' antigen were of γ1M and γ1A classes. Urinary antibodies to `H' antigen were of γ1A and 7S γ classes. No antibody activity could be detected in the low molecular weight γ-globulins of urine.