Accessory molecules and T cell activation. I. Antigen receptor avidity differentially influences T cell sensitivity to inhibition by monoclonal antibodies to LFA-1 and L3T4.
A series of BALB/c-derived T hybridoma cells, capable of producing interleukin 2 (IL 2) in response to poly(Glu60, Ala30, Tyr10) (GAT) presented by syngeneic B lymphoma cells in the context of Ad restriction determinants, was used as a model system to evaluate the roles of LFA-1 and L3T4 accessory molecules in antigen-specific T cell activation. Examination of the antigen requirement for optimal IL 2 responses revealed marked differences in the apparent avidity of these cells for GAT/Ad complexes. A relationship was observed between this parameter and the susceptibility of T hybridoma cells to inhibition by monoclonal antibodies directed at 5 distinct epitopes of LFA-1, and at A beta d allodeterminants. In contrast, L3T4a-specific monoclonal antibodies were found to block in a similar fashion the antigen-specific IL 2 responses of T hybridoma cells, regardless of the apparent avidity of their antigen receptors. It was also shown that both L3T4+ and L3T4- T hybridoma cells were capable of recognizing GAT plus Ad with high avidity. Thus, the quality of T cell antigen recognition appears to critically influence the involvement of LFA-1, and only to a marginal extent that of L3T4, in antigen-specific T cell activation. The implications of these findings are discussed in the context of recent data indicating that L3T4 may not only be an Ia-binding protein.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007376:Interleukin-2; D016169:Lymphocyte Function-Associated Antigen-1; D011948:Receptors, Antigen, T-Cell