1987 Volume 54 Issue 2 Pages 128-140
A new type of amphipathic antigen was purified from phenol-water extracts of whole cells and culture supernatant of Streptococcus sanguis ATCC 10557 (biotype B, serotype II) and characterized as a fatty acid-substituted heteropolysaccharide.
The phenol-water extract was applied to columns of Sepharose 6B and octyl-Sepharose CL-4B. Immunologic activity of each fraction was checked by passive heamagglutination (PHA) and immunodiffusion tests against anti-10557 serum obtained by immunizing rabbits with whole cells of strain ATCC 10557. Gel filtration of the extract on a column of Sepharose 6B showed that strong PHA activity was present in the first hexose-containing fraction eluted near the void volume, indicating that this fraction contained an amphipathic antigen. Chromatography of this fraction on a column of octyl-Sepharose CL-4B showed that strong PHA activity existed in the hexose-containing peak which was eluted with 33% (v/v) n-propanol. This peak contained only 1% of phosphorus, indicating that the cells of strain ATCC 10557 posess an amphipathic antigen which differs from lipoteichoic acids that are common in many Gram-positive bacterial strains. This amphipathic antigen was a fatty acid-substituted heteropolysaccharide composed of mannose, glucose, galactose, rhamnose, galactosamine, glycerol and fatty acids in a molar ratio of approximately 4.3 : 1.0 : 1.5 : 0.6: 0.5: 0.1: 0.9. The PHA reaction was inhibited in the presence of polymelized mannose.
The second hexose-containing peak in the chromatography of Sepharose 6B produced a heavy band against anti-10557 serum in immunodiffusion test but had no PHA activity. The isolated material of this peak contained glucose, galactose, rhamnose and N-acetylgalactosamine in a molar ratio of approximately 1.0 : 1.4 : 0.8: 0.8, which was essentially identical to serotype II carbohydrate antigen reported previously.
