Characterization of Campylobacter cinaedi and C. fennelliae antigens and analysis of the human immune response.

Whole-cell protein patterns of Campylobacter cinaedi and C. fennelliae, identified by SDS-PAGE, differed from one another and from five other catalase-positive Campylobacter species. When immunoblotted with rabbit antisera, C. cinaedi and C. fennelliae showed antigenic profiles that were highly species-specific and had little or no cross-reactivity with antigens of the other Campylobacter species tested. Antibody responses of 13 homosexual men with C. cinaedi infection demonstrated consistent reactions with five antigens (96-41 kDa). All human sera tested, including those of 10 culture-negative individuals, reacted with the C. cinaedi 59- and 64-kDa bands, but the overall responses of infected individuals were much stronger. The antigenic profiles of C. cinaedi and C. fennelliae can be used to distinguish these species from other Campylobacter species. At least six C. cinaedi antigens are immunogenic in humans.