Cell surface antigen of encapsulated Staphylococcus epidermidis SE-360 protects mice from homologous infection

Cell surface antigen was mechanically extracted from encapsulated strain SE-360 of Staphylococcus epidermidis and purified by DEAE-Sephadex A 25 (Cl- form) ion exchange chromatography. This antigen manifested type-specific activity and major sugar constituents were galactose, glucose and N-acetyl-glucosamine at the molar ratio 1.00:9.05:1.65. alpha-D-glucosyl- and N-acetyl-glucosaminyl-residues were closely correlated to the antigenic determinant. In mice, protection against homologous microorganisms could be achieved by active immunization with thus purified antigen. Type-specific opsonin in rabbit anti-SE-360 serum could also be absorbed.