Group and type antigens of Capnocytophaga.

Group-specific and type-specific antigens have been identified and purified from sonic extracts of Capnocytophaga. The group-specific antigen, which was purified by affinity chromatography, was found to be identical to an antigen present in all 26 strains tested. The antigen is sensitive to trypsin, sodium dodecyl sulfate and heat labile, and composed predominantly (55%) of protein. The type-specific antigen, which was obtained by preparative immunoelectrophoresis, was found to be present in only 3 of the 26 strains tested. This antigen was resistant to heat, trypsin, and sodium dodecyl sulfate and was primarily composed of carbohydrate (47% phenol-sulfuric acid-positive material, 8% amino sugar). Agglutination and fluorescent antibody data suggest that both the group- and type-specific antigens reside on the cell surface.