The isolation and immunochemical characterisation of a cell-wall carbohydrate and a membrane lipocarbohydrate antigen of group B streptococcus, type II.

Two distinct carbohydrate antigens were isolated from the cell surface of group B streptococcus, type II. One antigen was extracted from SDS-purified cell walls by cold trichloroacetic acid and contained galactose, glucose, rhamnose, glucosamine and sialic acid in the approximate molar proportions 1.7:1.0:3.4:0.9:0.21 respectively. The serological activity of this polymer indicated that it is the group-specific antigen common to all group B streptococci. The second antigen was extracted by phenol from cell membranes and contained galactose, glucose, glucosamine, phosphorus and fatty acid in a molar ratio of 1.6:1.0:0.35:2.6:0.016 respectively. This antigen was shown to be specific for type II, group B streptococcus.