Isolation and characterization of a common antigen in Campylobacter jejuni and Campylobacter coli

Flagellin protein was isolated and purified from two serotype reference strains of Campylobacter jejuni, Pen 1 and Pen 3. Each preparation was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to consist of a diffuse band with a molecular mass of approximately 62 kilodaltons. Antisera were prepared against flagellin from Pen 1, and specific antibody was isolated by affinity chromatography with flagellin protein covalently bound to cyanogen bromide-activated Sepharose. The high-affinity antibody was used to immune blot purified flagellin from Pen 1 and Pen 3, as well as whole-cell preparations and acid-glycine extracts from the 60 reference strains of the thermostable antigen serotyping system. From each of the 60 strains, a protein with a molecular mass of approximately 62 kilodaltons was identified which shared a common antigenic determinant. When the affinity-purified antibody was used in a coagglutination assay, washed whole cells were not agglutinable unless they had been pretreated with an acid buffer (glycine-hydrochloride [pH 2.0]). This indicated that the antigenic determinant common to strains of both C. jejuni and Campylobacter coli may not be exposed in the native state.