Nonlipopolysaccharide surface antigens of Campylobacter species.

Among the protein antigens of Campylobacter species, flagellin, the subunit of the flagellar filament, is the best characterized. The motility imparted by this locomotory organelle is absolutely essential for Campylobacter organisms to colonize the gastrointestinal tract and to cause diarrheal disease. Flagellin is the immunodominant protein recognized during infection and has been suggested to be involved in the protective immune response. Campylobacter flagellins are glycosylated, which is an unusual posttranslational modification for prokaryotic proteins. Although the chemical structure of the glycosylated moiety is undetermined, the posttranslational modification includes sialic acid. The association of glycosylated flagellin with development of Guillain-Barré syndrome remains speculative, but the possibility of molecular mimicry between glycosylated flagellin and eukaryotic glycoproteins exists.