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Carbohydrate antigens of the serotype k/Lancefield group G "Streptococcus milleri" were extracted by autoclaving whole cells of the type k reference strain Streptococcus anginosus K214-2K. The type k and group G antigen molecules are separated from each other and partially purified by a DEAE-Sephadex A-25 column chromatography followed by a Sephadex G-100 gel filtration. In the double diffusion and the immunoelectrophoresis, the type k and group G antigen preparations obtained yielded single bands with their homologous antisera respectively. The type k antigen preparation contained principally glycerol, rhamnose, ribitol, galactose and glucose in a molar ratio of 0.54:1.20:0.43:0.33:1.00. The quantitative precipitin inhibition test indicated that β(1-6)glucosyl-glucose (gentiobiose) sequence played a major role in immunodeterminant structure. Thus, the type k antigen of "S. milleri" appears to be a new carbohydrate type antigen that is chemically different from any Ottens type antigen. In contrast, the group G antigen preparation contained high proportion of rhamnose in addition to glucose, N-acetylglucosamine and N-acetylgalactosamine in a molar ratio of 6.45:1.00:0.24:1.15, and the rhamnose residue was involved in the immunodominant epitope, being in good agreement with the previously proposed chemical structure of the group antigen. [ABSTRACT FROM AUTHOR]

Carbohydrate antigens of the serotype c/Lancefield group C "Streptococcus milleri" were extracted by autoclaving whole cells of the type c reference strain K51 Y. The type c and group C antigen molecules were separated and partially purified by a DEAE-Sephadex A-25 column chromatogiaphy followed by Sephadex G-100 gel filtration, The purified type c antigen and group C antigen were homogeneous in the double diffusion and in the immunoelectophoresis. The type C antigen was composed principally of glycerol, rhamnose, glucose and N-acetylglucosamine in a molar ratio of 0.22; 0.27: 100: 0.48. The quantitative precipitin inhibition test indicated that N-acetylglucosamine played a major role in immunodeterminant structure. Thus, tile type c antigen of "S. milleri" is a new carbohydrate type antigen and is immunochemically different from the Ottens-type antigen III found occasionally in group C streptococci. In contrast, the group C antigen preparation contained a high proportion of N-acctylgalactosamme in addition to glycerol, rhamnose, glucose and N-acetylglucosamine, and the N- acetylgalactosamine , residue was involved in the immunodominant epitope, being in good agreement with the previously proposed chemical structure of the group antigen N-acetylgalactosamine was detected in the autoclaved extracts of a nontypeable/group C strain but not of a type c/ungroupable strain. [ABSTRACT FROM AUTHOR]