Regulation of the Antibody Response to Type III Pneumococcal Polysaccharide

Prior treatment with a marginally immunogenic dose of Type III pneumococcal polysaccharide (SSS-III) resulted in the development of an unresponsive state. Such low-dose paralysis, which is antigen-specific, could not be induced in athymic nude mice and could be abrogated by treatment with anti-lymphocyte serum (ALS), a procedure reported to inactivate thymic-derived suppressor cells (suppressor T cells). These findings provide support for the view that low-dose paralysis to SSS-III is a T cell-dependent phenomenon in which suppressor T cells, activated by low doses of antigen, play a major role.