Immunological studies of aging. XI. Age-related changes in idiotype repertoire of suppressor T cells stimulated during tolerance induction.

Tolerance was induced in young and old mice by the i.v. injection of TNP-modified syngeneic spleen cells. The tolerant state was associated with the development of hapten-specific suppressor T cells. The specificity of suppressor T cells was studied by transferring T cells from tolerant donors to normal, nonirradiated, syngeneic recipients, which were then immunized with TNP-Ficoll or TNP-bovine gamma-globulin. Suppressor T cells induced in young mice depressed the plaque-forming cell response of young but not old mice to both antigens. Similarly, suppressor T cells induced in old mice depressed the response in old but not young mice. These findings suggest that aging is associated with changes in idiotype repertoire which influence the specificity of the suppressor T cells present in tolerant mice.