Acid and alkaline Campylobacter extracts in the demonstration of antibody response in hyperimmunized rabbits

Acid and alkaline extracts from several Campylobacter strains were used as antigens in enzyme immunoassay (EIA). Antibodies were detected in rabbits immunized with formalin-treated, boiled, or autoclaved whole bacteria of different Campylobacter subspecies. For the preparation of the extracts, three Campylobacter fetus subsp. venerealis strains, three Campylobacter fetus subsp. fetus strains, four Campylobacter coli, and five Campylobacter jejuni strains were used. The acid extracts of Campylobacter fetus subsp. fetus and Campylobacter fetus subsp. venerealis were antigenically similar to each other but different from Campylobacter coli and Campylobacter jejuni strains. These acid extracts were found to be suitable antigens in enzyme immunoassay. However, when alkaline extracts were used as the antigen, fewer antisera reacted with them than with the acid extracts, and many pre-immune sera gave high values.