title: Function of the LFA-1 and T4 molecules in the direct activation of resting human B lymphocytes by T lymphocytes.
abstract: Activated T lymphocytes can provide all of the signals necessary to induce the proliferation of resting B lymphocytes. The activation signal is presumably initiated through direct T-B lymphocyte contact. The role of the leukocyte function antigen-1 (LFA-1) and T4 molecules in the activation of purified, small B lymphocytes by mitomycin C-treated T lymphocytes was examined by using monoclonal antibodies that react with and inhibit the function of these molecules. Anti-LFA-1 antibody binding significantly inhibited T-B lymphocyte interactions that result in B lymphocyte proliferation. In contrast, the presence of anti-T4 antibodies at concentrations as high as 100 micrograms/ml did not inhibit this interaction. These results indicate that the B lymphocyte activation signal may not be mediated through the interaction of T4 molecules with major histocompatibility complex class II antigens of the B lymphocyte but is a cell-cell contact-dependent event that is facilitated by LFA-1 molecules.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000917:Antibody Formation; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D002450:Cell Communication; D006801:Humans; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D016169:Lymphocyte Function-Associated Antigen-1