Regulatory role of suppressor T cells in the expression of delayed-type hypersensitivity in mice. I. Transient appearance of suppressor T cells for the expression of delayed footpad reaction induced with lipid-conjugated lysozyme.

Delayed footpad reaction (FPR) to lysozyme (Lys) in mice was induced without antibody responses by lipid-conjugated lysozyme (D.Lys). This FPR was suppressed by priming s.c. with a high dose (10 mg) of Lys 2 weeks previously (unresponsiveness). Spleen cells from the unresponsive mice suppressed antigen-specifically FPR in mice previously immunized with D.Lys, and also suppressed passive transfer of FPR by D.Lys-immune lymphoid cells into normal mice. The suppressive activity of the spleen cells was abolished by treatment with anti-phi anti-serum and complement. The suppressor cells occurred also in the thymus of unresponsive mice. Unresponsiveness was induced in mice immediately after priming with Lys and persisted at least up to 7 weeks after the induction. In contrast, suppressor cells appeared only 2 weeks after induction of unresponsiveness in both the spleen and the thymus but were no longer detectable 3-7 weeks later, although donor mice remained fully unresponsive. These results suggest that antigen-specific suppressor T cells are involved in the regulation of the expression of FPR only for a definite period of time in unresponsive mice.