title: Evidence for the separate human T-lymphocyte subpopulations that collaborate with autologous monocyte/macrophages in the elaboration of colony-stimulating activity and those that suppress this collaboration.
abstract: We investigated the interaction of monocyte/macrophages and autologous T lymphocytes in the methanol extraction residue (MER) of BCG-induced production of granulocyte-macrophage colony-stimulating activity (CSA). Coincubation of monocyte/macrophages and T lymphocytes at a 1:3 ratio produces an optimum collaboration; a change to a 1:9 ratio diminished this collaboration. Coincubation of monocyte/macrophages and T lymphocytes primed with lithium carbonate (2 meq/liter) for 40 hr synergistically increased CSA elaboration and prevented the decline in CSA noted for the 1:9 monocyte/macrophage: T lymphocyte ratio. In contrast, concanavalin-A-primed T lymphocytes did not enhance CSA elaboration at any monocyte/macrophage:T lymphocyte ratio except, occasionally, at 1:9. However, this was overcome if the T lymphocytes were primed with both concanavalin-A and lithium carbonate before their coincubation with monocyte/macrophages. Further cell-mixing experiments revealed that concanavalin-A-primed T lymphocytes contained a subpopulation that suppressed monocyte/macrophage and T-lymphocyte collaboration. Activation of suppressor T lymphocytes could be effectively prevented by lithium carbonate and, in a dose-dependent manner, by irradiation. Also, suppressor T lymphocytes not only diminished the elaboration of colony-stimulating factor(s), but also elaborated an inhibitor of granulocyte-macrophage colony-forming cells. We further demonstrated that the respective hemopoietic helper and suppressor T-lymphocyte activities could be enriched with OKT8- (or OKT4+) and OKT8+ subpopulations.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D001500:BCG Vaccine / Q000494:pharmacology; D002450:Cell Communication; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D008094:Lithium / Q000494:pharmacology; D008264:Macrophages / Q000502:physiology*; D009000:Monocytes / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology / Q000502:physiology / Q000528:radiation effects
chemical_list: D000911:Antibodies, Monoclonal; D001500:BCG Vaccine; C011499:methanol extraction residue (MER) tubercle bacillus fraction; D003208:Concanavalin A; D008094:Lithium