Induction of immunoglobulin-secreting cells in the allogeneic mixed leukocyte reaction: regulation by helper and suppressor lymphocyte subsets in man.
The existence of functionally distinct T lymphocyte subsets in man, initially demonstrated with heteroantisera, has been confirmed with monoclonal reagents. Two major subsets have been defined: Leu-2 cells, which effect cell mediated lymphocytotoxicity (CML), and Leu-3 cells, which amplify CML and other T cell functions. This study is an effort to determine the effects of these subsets on the immunoglobulin secretion induced in the human mixed leukocyte reaction (MLR). T cells were separated from non-T cells by rosetting with sheep erythrocytes and were fractionated into Leu-2 and Leu-3 subsets by solid phase immunoabsorption with monoclonal antibodies. T cell subsets were cultured with autologous non-T cells and irradiated allogeneic stimulator non-T cells. Secretion of IgM and IgG was measured by a reverse hemolytic plaque assay. MLR-induced antibody secretion was specifically dependent on the Leu-3 T lymphocyte subset. The Leu-2 subset was incapable of generating large numbers of IgM- or IgG-secreting cells, and, in fact, suppressed the Leu-3-induced response. Exposure of Leu-3 cells to a dose of irradiation sufficient to prevent their proliferation in MLR did not reduce induced immunoglobulin secretion. Leu-2-mediated suppression, however, was sensitive to low dose irradiation. Thus Ig secretion in human MLR is regulated by a balance of helper activity from the Leu-3 subset and suppressor activity from the Leu-2 subset.
D000921:Antibody-Producing Cells / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000145:classification; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology*
D007136:Immunoglobulins