Assay dependent specificities of monoclonal antibodies to bacterial antigens

Six rat monoclonal antibodies, all of the IgG2b class, were generated from rats immunized with the 35A3 (Inaba) and NIH-41 (Ogawa) strain of Vibrio cholerae and selected by enzyme-linked immunosorbent assay (ELISA) on the whole organisms. When the fine specificity was dissected by several different immunological assays, the antibodies could be divided into three groups, each with a different specificity profile. Two antibodies were totally specific to the Ogawa serotype on all assays, three had a preference for Inaba but could be shown to display assay dependent cross reactions of variable intensity with Ogawa. The sixth showed total specificity for Ogawa on some assay systems, apparent total specificity for Inaba on others, and variable reaction with both serotypes on yet other assay systems. The data emphasize that it is possible to produce antibodies which do not conform to the conventional serological classification of antigens and that specificity is highly dependent on method of assessment.