Naturally occurring cellular and humoral immunity to teichoic acid in rats.

Naturally occurring cellular and humoral immunity to a purified polyglycerophosphate (teichoic acid) have been observed in normal albino rats. Skin tests as well as correlates of delayed hypersensitivity yielded positive results in more than 50 per cent of rats between the ages of 24 and 40 weeks while rats 6–20 weeks old exhibited no cellular responses. Passive haemagglutination assays for natural antibodies to glycerol—teichoic acid revealed their occurrence in all rats between the ages of 6–20 weeks as well as in most of the older rats examined. These antibodies were usually found in the IgM fraction, but some animals possessed them in the IgG-containing fraction. The regular appearance of antibodies before the appearance of cellular response, if confirmed, may imply that B-cell responses precede T-cell responses in certain circumstances.