Immunochemical characterization of lipoteichoic acid and other amphipathic antigens from oral streptococci

Abstract

Distribution of amphipathic antigens in oral streptococci was studied by passive hemagglutination test. Lipoteichoic acid (LTA) was detected in all phenol-water (PW) extracts from the lyophilized cells of Streptococcus mutans, S. salivarius and S. milleri. On the other hand, LTA was not detected in the PW extracts from 28 strains among 82 strains of S. sanguis or S. mitior. These LTA-negative strains showed similar biological properties except the ability to produce glucan from sucrose. The PW extracts obtained from LTA-positive and negative strains showed different chromatographic patterns on Sepharose 6B column. LTA-negatitve streptococci were divided into 3 serological groups using the antisera immunized with the whole cells of LTA-negative S. sanguis/S. mitior strains. The sheep red blood cells sensitized with the PW extracts from some LTA-negative strains were agglutinated by one of these antisera. These results strongly indicate the presence of amphipathic antigen in some strains of S. sanguis and S. mitior that is immunologically different from LTA.