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Identification of T lymphocyte subpopulations that regulate elaboration of granulocyte‐macrophage colony stimulating factor
Author(s) -
Verma Dharmvir S.,
Johnston Dennis A.,
McCredie Kenneth B.
Publication year - 1984
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1984.tb02925.x
Subject(s) - t lymphocyte , granulocyte , microbiology and biotechnology , monocyte , granulocyte macrophage colony stimulating factor , immunology , biology , medicine , immune system , endocrinology , cytokine
S ummary. To determine the role of T lymphocytes (TL) that bear Fc receptors for IgG (T γ+ ) and IgM (T μ+ ) and of those that do not (T γ‐ and T μ‐ ) in the elaboration of granulocyte‐macrophage colony‐stimulating activity (GM‐CSA), we coincubated TL or the TL subpopulations in varying proportions with a constant concentration of autologous monocyte‐macrophages (MΦ) along with methanol extraction residue of BCG (MER). These conditioned media (CM) were assayed for GM‐CSA. MΦ and TL interacted maximally at 1:3–1:6 ratios, significantly less so at a 1:9 ratio. Coincubation of MΦ with T γ‐ fraction markedly enhanced GM‐CSA elaboration at all MΦ:T γ‐ ratios, progressively increasing colony‐stimulating activity as the proportion of T γ‐ cells increased. MΦ interacted with the T γ‐ fraction significantly better ( P = 0.001) at all the ratios tested than it did with the T γ‐μ+ or T γ‐μ‐ subsets, suggesting that the T γ‐μ+ and T γ‐μ‐ subsets must interact. Coincubation of the T γ+ fraction synergistically enhanced GM‐CSA elaboration only at MΦ:T γ+ ratios of 1:1.5 and 1:3. Further increases in the proportion of T γ+ cells rapidly and progressively decreased the capacity of the CM to stimulate granulocyte‐macrophage colony‐forming cells (GM‐CFC). Also, inclusion of T γ+ cells in the coincubation mixtures of MΦ and T γ‐ fraction significantly suppressed GM‐CSA elaboration. Dose‐response curves and CM‐mixing experiments revealed that the CM from coincubation of MΦ and T γ+ not only contained smaller amounts of stimulating factors but also contained a GM‐CFC inhibitor. Experiments also demonstrated that the suppressor subpopulation enriched with the T γ+ fraction was radiosensitive. These results suggest that the elaboration of GM‐CSA is controlled by helper and suppressor subpopulations that are enriched with T γ‐ and T γ+ fractions, respectively. Furthermore, the suppressor effect is radiosensitive.