Interaction of human thymus-derived and non-thymus-derived lymphocytes in vitro. Induction of proliferation and antibody synthesis in B lymphocytes by a soluble factor released from antigen-stimulated T lymphocytes.
Relatively pure populations of human T and B lymphocytes were obtained from blood and tonsils using density gradient centrifugation in bovine serum albumin. Antigen alone was incapable of triggering the B lymphocyte into blast transformation or to secrete antibody. However, supernatants from tetanus toxoid-stimulated T cells obtained from immune donors contained a factor mitogenic for B lymphocytes. 50-60% of B cells responded to this lymphocyte mitogenic factor (LMF) by proliferation, loss of C3 reactivity, and change to a secretory state. LMF-stimulated B cells exhibited a three- to fivefold increase in protein secretion and a six- to eightfold increase in gamma G globulin secretion. De novo secreted IgG had specificity directed to the tetanus toxoid present in the LMF containing T-cell supernatants. This was confirmed by an increase in the number of indirect plaque-forming cells to tetanus toxoid-coated sheep red blood cells after stimulation of B cells with LMF. It is proposed that in the course of the response to a previously encountered protein antigen, sensitized human T cells emit a signal in the form of a soluble product that, together with antigen, triggers B cells into division and antibody secretion. The experimental model utilized can be adapted to study human T-B cell cooperation under various conditions in normal individuals and in individuals with immunodeficiency diseases.
D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells; D000937:Antigen-Antibody Reactions; D001345:Autoradiography; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001798:Blood Proteins / Q000032:analysis / Q000096:biosynthesis; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D008934:Mitogens; D014066:Palatine Tonsil / Q000276:immunology; D012710:Serum Albumin, Bovine; D012756:Sheep / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D001798:Blood Proteins; D008934:Mitogens; D012710:Serum Albumin, Bovine; D004247:DNA