Western blot analysis of the human antibody response to Campylobacter jejuni cellular antigens during gastrointestinal infection.

Western blot analysis was used to identify antigenic components of Campylobacter jejuni whole cells and outer membranes that elicit antibody responses in patients with campylobacter enteritis. Acute- and convalescent-phase sera from eight patients were analyzed for antibody activity against their homologous infecting strains and heterologous clinical isolates. Whole-cell and Sarkosyl-insoluble membrane components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred electrophoretically to nitrocellulose paper for immunoblotting experiments. After the separated components were probed with patient sera, antibody binding was detected by autoradiography with 125I-protein A. Using this method, we detected several immunogenic components in whole cells and outer membranes. In the acute-phase response of some patients to infection, two to three components with approximate molecular weights of 66,000 (p66), 43,000 to 46,000 (major outer membrane protein), and 12,000 (p12) were detected in immunoblots. Convalescent-phase sera showed a more broad array of antibody binding to cell components. p66, shown to be campylobacter flagellin, was the major immunodominant component in almost all sera tested, however, p66 was not a major protein in Coomassie blue-stained gels. The major outer-membrane protein also bound to antibody, but with less intensity than p66. In general, the antibody specificity of patient sera was not limited to the homologous infecting strain, and antibodies cross-reacted with most components in heterologous strains. A low-molecular-weight component, identified as lipopolysaccharide with a modified silver stain, showed serological specificity for some patient sera. The results of this study showed that the antibody response of patients with campylobacter enteritis to C. jejuni antigens is variable. Flagellin appeared to be the major immunodominant component during infection.