Enzyme-linked immunosorbent assays for the detection of Neisseria gonorrhoeae specific antibodies

Abstract

An indirect enzyme-linked immunosorbent assay (ELISA) using rigid polystyrene microtiter plates was adapted to detect specific gonococcal antibodies against outer membrane-complex antigens extracted from N. gonorrhoeae. The concentration of antigen to obtain maximum coating of the well was 10 .mu.g protein/ml. The optimal binding of the primary antibody and enzyme-conjugated antiimmunoglobulin was achieved after 1 h at 37.degree. C. Under these conditions using gonococcal antisera [from rabbits], no cross-reactivity was observed with outer membrane antigens extracted from N. meningitidis serogroups B, C, X, Y and W135. N. meningitidis serogroup A demonstrated low levels of cross-reactivity. All the non-pathogenic Neisseria spp. tested were negative (absorbance value at 400 nm/30 min < 0.15). The reaction of immune serum against outer membrane complex adsorbed to the microwells was completely inhibited with soluble-specific antigen but not with purified N. gonorrhoeae lipopolysaccharide. Quantitative inhibition permitted the measurement of low levels of antigen (0.5 .mu.g/ml). The detection of N. gonorrhoeae antibody with ELISA is specific and highly sensitive.