Quantitation of Salmonella O-antibodies in human sera by enzyme-linked immunosorbent assay (ELISA).

The enzyme-linked immunosorbent assay (ELISA) has been applied to the detection of antibodies against Salmonella O-antigens in human sera. Phenol-water extracted lipopolysaccharides (LPS) from serogroups A (O-antigens 2, 12), B (4, 5, 12) and D (9, 12) were used as antigens. When compared to the tube agglutination method according to Widal employing sera from patients with verified or suspected typhoid--or paratyphoid fever and from healthy controls it was found that ELISA (i) correlated significantly with the Widal reaction, (ii) was up to 100-fold more sensitive, and (iii) showed a greater reproducibility.