Human T cell subpopulations defined by a monoclonal antibody. II. Evidence for cell cooperation in the response to alloantigens and generation of cytolytic cells.
It has been shown previously that the 5/9 monoclonal antibody defines a small T cell subpopulation in human peripheral blood that includes all the cells responsible for proliferation to tetanus toxoid and to alloantigens as well as the helper cells for B cell differentiation. In the present study, human peripheral blood T cells were fractionated according to their reactivity with the 5/9 monoclonal antibody and stimulated in mixed lymphocyte culture (MLC). In spite of a strong proliferative response in MLC, 5/9+ cells generated no cytolytic activity against PHA-activated lymphocytes bearing the stimulating alloantigens (CTL activity) or against the K562 human cell line (NK activity). The precursors of these cytolytic effector cells were present in the 5/9- fraction. However, 5/9+ cells or soluble factors derived from 5/9+ cells were needed to induce 5/9- cells to respond in MLC and develop cytolytic activity. Both 5/9+ and 5/9- cell populations, upon MLC stimulation, were able to lyse L1210 mouse lymphoma cells in the presence of specific antibodies (ADCC).
D000818:Animals; D000911:Antibodies, Monoclonal; D000920:Antibody-Dependent Cell Cytotoxicity; D002417:Cattle; D006801:Humans; D007519:Isoantigens; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D011961:Receptors, Fc; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
D000911:Antibodies, Monoclonal; D007519:Isoantigens; D011961:Receptors, Fc