Cytolytic T lymphocyte clones that proliferate autonomously to specific alloantigenic stimulation. II. Relationship of the Lyt-2 molecular complex to cytolytic activity, proliferation, and lymphokine secretion.
Previous analyses of the inhibitory effects of anti-Lyt-2 monoclonal antibodies (mAb) on cytolytic activity suggested that Lyt-2/3 antigens expressed on the surface of murine cytolytic T lymphocytes (CTL) are involved in antigen recognition. In the present study, we investigated the effects of anti-Lyt-2 mAb (in the absence of complement) on the functional activities of H-2K/D-specific Lyt-2+ CTL clones that proliferate to antigenic stimulation in the absence of helper T cells or added interleukin 2 (IL 2) and secrete lymphokines. For those clones that were inhibited in cytolysis by anti-Lyt-2 mAb, a parallel inhibition of antigen-dependent proliferation and lymphokine secretion (interferon, macrophage-activating factor) was observed. Inhibition of proliferation or lymphokine secretion could be overcome by the addition of IL 2 or lectin, respectively. Collectively, these results would strongly suggest that anti-Lyt-2 mAb were inhibiting CTL antigen recognition. Not all CTL clones, however, were inhibited in cytolysis by anti-Lyt-2 mAb, in which case proliferation and lymphokine secretion were similarly unaffected. This heterogeneity of Lyt-2+ CTL clones in their susceptibility to inhibition of cytolytic activity, proliferation, and lymphokine secretion by anti-Lyt-2 mAb is discussed in the context of a model proposing that Lyt-2/3 molecules function to stabilize the interaction between CTL receptors and the corresponding target/stimulating cell antigens. Such a stabilization may be required by CTL possessing few and/or low affinity receptors.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D015478:Antigens, Heterophile / Q000235:genetics; D001667:Binding, Competitive; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D005260:Female; D007376:Interleukin-2 / Q000502:physiology; D007518:Isoantibodies / Q000502:physiology; D007519:Isoantigens / Q000276:immunology*; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis*; D051379:Mice; D008811:Mice, Inbred DBA; D051381:Rats; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015478:Antigens, Heterophile; D000939:Epitopes; D007376:Interleukin-2; D007518:Isoantibodies; D007519:Isoantigens; D008222:Lymphokines; C029805:Lyt antibodies