Interaction between MHC-encoded products and cloned T cells

The interaction between class I major histocompatibility complex (MHC) products and T cells was studied using H-2K^b-specific alloreactive T-cell lines and clones obtained by repeated in vitro stimulation with allogeneic cells. Induction of proliferation of these T cells appeared to involve two signals: the H-2K^b alloantigen and interleukins. Immunopurified liposome-inserted H-2K^b, which stimulates specific secondary in vitro cytotoxic T lymphocyte (CTL) responses, could not replace cell-associated H-2K^b in the stimulation of these T-cell lines, even in the presence of feeder cells and interleukins. When T-cell lines were initiated in vitro and repeatedly stimulated with H-2K^b liposomes and feeder cells, it was possible to obtain T cells that could proliferate in response to H-2K^b liposomes in the presence of feeder cells and interleukin-2-containing supernatants or on H-2K ^b -expressing cells. Only stimulation with cells permitted maintenance of these T cells in culture for more than 12 weeks. Analyses of cell surface markers and of patterns of inhibition of proliferation by monoclonal antibodies (mAb) of T-cell lines induced in vitro with cell- or liposome-associated H-2K^b indicated that T-cell stimulation by class I antigen can occur in at least two ways. In the first, the H-2K^b-induced proliferation of Lyt-1^- Lyt-2⁺ T4^- T cells is inhibited by H-2K^b- and by Lyt-2-specific mAb, but not by Ia or T4-specific mAb. In the second, both Lyt-2⁺ and T4⁺ T cells are involved and the H-2K^b-induced proliferation is inhibited by H-2K^b- and Lyt-2-specific mAb and by Ia- and T4-specific mAb.Abbreviations used in this paper Ab antibody - mAb monoclonal antibody - C complement - i.p. intraperitoneally - PBS phosphate-buffered saline - PBS-B-N PBS containing bovine serum albumin and NaN₃ - CTL cytotoxic T lymphocyte - Th T helper cell - MHC major histocompatibility complex - PMA 4-phorbol 12-myristate 13-acetate - SCA concanavalin A-stimulated rat spleen cell supernatant - SC16 EL4 clone 16 supernatant - IL-1 interleukin-1 - IL-2 interleukin-2 (T-cell growth factor) - FCS fetal calf serum - H-2K^b-lip. H-2K^b inserted in liposomes - C. E. cell equivalents