Carbohydrate antigen of serotype g "Streptococcus milleri": immunochemical characterization

Cell wall carbohydrate antigen of the serotype g "Streptococcus milleri" was extracted with cold trichloroacetic acid from purified cell walls of the type strain K1K. The extracts were then purified by a DEAE-Sephadex A-25 column, followed by a Sephadex G-100 column. The immunoelectrophoresis revealed that the serotype g carbohydrate antigen preparation displayed a single precipitin band against the crude anti-K1K serum. The purified type g antigen consisted of rhamnose, galactose, glucose and galactosamine in a ratio of 1.3:3.8:1.0:2.5. The quantitative precipitin inhibition test with various haptens indicated that galactosamine is a major immunodeterminant of the type g-specific antigen.