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Properties of a protective protein antigen of Erysipelothrix rhusiopathiae
1Gluck Equine Research Center, University of Kentucky, Lexington.
Abstract:
Erysipelothrix rhusiopathiae is a widely distributed mucosal commensal of the alimentary tracts of vertebrates. Antibodies to a 66-64 kDa protein released from the cell surface have been shown to be involved in protective immunity. Mice immunized with the purified 66-64 kDa 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-proteinaceous antigens are the type specific antigens useful in serotyping. The 66-64 kDa 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 66-64 kDa 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.
Insights
Antibodies targeting a 66-64 kDa protein from Erysipelothrix rhusiopathiae offer broad protection against infection, irrespective of serotype. This protein shows potential for developing new vaccine testing methods.
Area of Science:
- Veterinary Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Erysipelothrix rhusiopathiae is a common bacterium found in vertebrate digestive systems.
- Immunity against E. rhusiopathiae involves antibodies to a cell surface protein of 66-64 kDa.
- Serotyping relies on polysaccharide antigens, indicating protein antigens may confer broader protection.
Purpose of the Study:
- To investigate the protective immunity conferred by a 66-64 kDa protein from E. rhusiopathiae.
- To determine if protection is serotype-specific.
- To explore the immunogenicity of the 66-64 kDa protein when complexed with glycolipid.
Main Methods:
- Mice were immunized with purified 66-64 kDa protein from E. rhusiopathiae strain T28 (serotype 2b).
- Immunized mice were challenged with different E. rhusiopathiae strains (serotype 1a and serotype N).
- Immunogenicity of the protein was assessed when complexed with glycolipid.
Main Results:
- Immunization with the 66-64 kDa protein provided protection against challenge with heterologous serotypes (1a and N).
- Protection was not limited to the homologous serotype, suggesting non-serotype-specific immunity.
- The 66-64 kDa protein was most immunogenic when complexed with glycolipid, possibly due to adjuvant effects.
Conclusions:
- The 66-64 kDa protein of E. rhusiopathiae is a promising candidate for a broadly protective vaccine antigen.
- The non-serotype-specific nature of protection highlights the potential for a universal vaccine.
- Further research correlating antibody titers with protection could lead to an in vitro assay for vaccine efficacy testing.