The murine IL 2 receptor. II. Monoclonal anti-IL 2 receptor antibodies as specific inhibitors of T cell function in vitro.
We assessed the dependency of a variety of immune responses for IL 2 in vitro by using anti-IL 2 receptor monoclonal antibodies as specific inhibitors of IL 2 function. The generation of allogeneic cytotoxic T lymphocyte (CTL) responses and maximal thymocyte proliferation to phytohemagglutinin (PHA) and IL 1 was readily susceptible to inhibition by these antibodies. Furthermore, the IL 2 receptor-positive, IL 2-responsive cell in the CTL cultures expressed killer cell activity. A greater variability in susceptibility to anti-IL 2 receptor antibody inhibition was noted for proliferation of T cells to concanavalin A, PHA, or allogeneic cells. Under certain conditions, however, each of these responses was almost completely inhibited. In most instances, the failure to block a response could be accounted for by either high levels of endogenous IL 2 production or high density of cell surface IL 2 receptors, which represent two known variables that influence the level of inhibition by these antibodies. Analysis of IL 2 receptor expression by mitogen-stimulated T cells suggested that accessory cells may play a role in the optimal expression of the IL 2 receptor. These experiments demonstrate that IL 2 is the predominant growth factor by which T lymphocytes proliferate, but do not exclude the possibility of an IL 2-independent pathway for growth.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology*; D000918:Antibody Specificity; D007108:Immune Tolerance; D007376:Interleukin-2 / Q000378:metabolism / Q000502:physiology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000276:immunology*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D008934:Mitogens; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2