Effects of monoclonal antibodies directed against murine T lymphocyte cell surface antigens on lymphokine production by cloned T lymphocytes reactive with class I MHC or Mls alloantigens.

Monoclonal antibodies recognizing murine T lymphocyte cell surface structures implicated in T lymphocyte-mediated cytolysis, including Lyt-2, L3T4, LFA-1, and a cytolytic T lymphocyte (CTL) clonotypic determinant, were used as probes to investigate the role of these structures in lymphokine production by T cell clones induced by antigen or lectin. The clone-specific antibody 384.5 bound to and inhibited antigen-induced lymphokine production by the L3 CTL clone, but did not affect lymphokine production by other T cell clones. Antibodies against the T cell surface structures Lyt-2 or L3T4, which are expressed by mutually exclusive T cell subsets, inhibited antigen-induced lymphokine production by class I major histocompatibility complex (MHC) antigen-reactive CTL clones or an M1s-reactive helper T lymphocyte (HTL) clone, respectively. Antibody against the broadly distributed LFA-1 molecule inhibited antigen-induced lymphokine production by all of the clones tested. Lectin-induced lymphokine production by cloned T cells was not inhibited by the clonotypic antibody, anti-Lyt-2, or anti-LFA-1; slight inhibition of the HTL clone was observed with the anti-L3T4 antibody. None of these structures appear to be uniquely involved with a particular functional response. Our results suggest that each of these structures is involved with the interactions between the effector cell and the stimulating cell leading to lymphokine production.