Enzyme-linked immunoassays for antibodies against Vibrio cholerae

Glutaraldehyde-treated V. cholerae organisms bind firmly to the surfaces of plastic microELISA plates, thus providing a stable immobilized antigen for use in enzyme-linked immunosorbent assays (ELISA). Serum absorption and ELISA-inhibition experiments indicate that, in addition to detecting natural antibodies in normal rat serum, the immobilized antigen may be used to quantitate specific anti-V. cholerae antibodies induced in rats by injection of live organisms. Apart from serotypically specific anti-lipopolysaccharide (LPS) antibodies, the reaction with immobilized organisms seems to involve antibodies common to Inaba and Ogawa serotypes; it is suggested that these antibodies are primarily directed against antigens of the outer membrane protein complex of V. cholerae cells. These findings have led to the development of an indirect ELISA method which quantitates levels of antibodies that react with heat-sensitive surface antigens of V. cholerae without involvement of anti-LPS antibodies. When used in conjunction with the indirect LPS-ELISA, the test has been found to provide a more detailed description of the serum antibody responses of rats to parenteral injections of live V. cholerae than has been reported previously.