Abstract
Antigen a5 was isolated from strain 830 of S. aureus by autolysis in phosphate buffer followed by alcohol precipitation. Purification was principally achieved by affinity chromatography on wheat germ agglutinin ultrogel and on anti-S. aureus teichoic acid immunosorbent. The a5 antigen was weakly immunogenic in rabbits. Chemical analysis showed that a5 is a teichoic acid composed of ribitol phosphate, N-acetylglucosamine and alanine. It has similar physicochemical properties to the wall .beta.-N-acetylglucosamine ribitol teichoic acid of S. aureus but is serologically distinct.