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 pro tein released from the cell surface have been shown to be involved in protective immunity. Mice immunized with the purified 66-64 kDa protei n from strain T28, serotype 2b were protected against challenge by the United States challenge strain E1-6P (serotype 1a) and by the officia l German challenge strain Frankfurt 1 (serotype N). Thus, protection i s not serotype specific, a result consistent with previous observation s that polysaccharide, non-proteinaceous antigens are the type specifi c antigens useful in serotyping. The 66-64 kDa protein appears to be m ost immunogenic when complexed to glycolipid. This may be due to an ad juvant effect of polysaccharide antigens. Further studies on the corre lation between antibody titers to the 66-64 kDa protein and protection in pigs, turkeys and mice in vivo should be helpful in developing a b asis for an in vitro assay to replace the mouse protection test in vac cine testing.