title: Purified lymphocyte function-associated antigen-3 and T11 target structure are active in CD2-mediated T cell stimulation.
abstract: In this study we have used cells expressing LFA-3 or T11TS, the human and sheep forms of the ligand of CD2, as well as the purified LFA-3 and T11TS molecules themselves to study their effects on T cell activation via the CD2-mediated "alternative pathway". Sheep red blood cells, which bind to CD2 via T11TS in E-rosette formation, and human autologous monocytes, which express the LFA-3 molecule, both induce proliferation of resting T cells in the presence of per se submitogenic concentrations of anti-T11(2) plus anti-T11(3) monoclonal antibodies (mAb). This effect is blocked by mAb to LFA-3, T11TS and CD2 known to inhibit CD2-ligand interaction. In addition, purified LFA-3 and T11TS, when added at ng amounts to cultures containing submitogenic concentrations of anti-T11(2 + 3) mAb, are also strongly mitogenic for resting human T cells. Thus, both LFA-3 and T11TS are potent co-stimulators of the alternative pathway of T cell activation but by themselves do not provide a mitogenic signal. This finding is discussed with regard to a physiological role of CD2-LFA-3 interaction in T cell activation.
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology*; D000954:Antigens, Surface / Q000502:physiology*; D018801:CD2 Antigens; D002352:Carrier Proteins / Q000502:physiology*; D002448:Cell Adhesion; D008024:Ligands; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1; D009000:Monocytes / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology*; D012756:Sheep; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018801:CD2 Antigens; D002352:Carrier Proteins; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D011971:Receptors, Immunologic