Unresponsiveness in hapten-specific cytotoxic T lymphocytes. I. Characteristics of tolerance induction in adult mice.

These experiments concern the regulation of cytotoxic T lymphocytes (CTL). Here we describe the induction of unresponsiveness in TNP-specific cytotoxic cells generated in vitro. Previous work has shown that i.v. injection of water-soluble TNP (TNBS) prevents in vivo generation of TNP-specific CTL in C3H/HeN mice. In contrast, this report shows that the in vitro generation of TNP-specific CTL from similarly treated C3H/HeN mice is not inhibited. Nevertheless, unresponsiveness in CTL can be induced with TNBS. This unresponsiveness appears to be H-2 linked, since 3 strains of H-2d mice (BALB/c, DBA/2J, and B10.D2) were rendered unresponsive after a single injection of TNBS, whereas 3 strains of H-2k mice (C58/J, C3H/HeN, and CBA/J) were not. This CTL unresponsiveness is antigen specific in both induction and expression. The unresponsiveness is reversed by pretreatment with cyclophosphamide but not by adult thymectomy. Furthermore, the addition of supernatants from Con A-stimulated spleen cells to cultures containing the unresponsive responder cells enhanced the generation of cytotoxic activity. These results suggest that a) the ability to induce TNP-specific CTL unresponsiveness is linked to H-2 loci, b) a regulatory network is involved in the unresponsiveness, which is sensitive to cyclophosphamide but resistant to adult thymectomy, and c) at least 1 level of regulation involves amplifying T cells.