Properties of A Protective Protein Antigen of Erysipelothrix Rhusiopathiae

Erysipelothrix rhusiopathiae is a widely distributed mucosal commensal of the alimentary tracts of vertebrates. Antibodies to a 66-64kDa protein released from the cell surface have been shown to be involved in protective immunity. Mice immunized with the purified 66-64kDa protein from strain T28, serotype 2b were protected against challenge by the United States challenge strain E1-6P (serotype 1a) and by the official German challenge strain Frankfurt 1 (serotype N). Thus, protection is not serotype specific, a result consistent with previous observations that polysaccharide, non-protein-aceous antigens are the type specific antigens useful in serotyping. The 66-64kDa protein appears to be most immunogenic when complexed to glycolipid. This may be due to an adjuvant effect of polysaccharide antigens. Further studies on the correlation between antibody titers to the 66-64kDa protein and protection in pigs, turkeys and mice in vivo should be helpful in developing a basis for an in vitro assay to replace the mouse protection test in vaccine testing.