title: The regulatory role of interleukin 2-responsive T lymphocytes on human marrow granulopoiesis.
abstract: The effect of recombinant interleukin 2 (IL2) on marrow CFU-C colony formation was evaluated to define the role for T lymphocytes in human marrow granulopoiesis. The colony-stimulating factor (CSA) used in our experiments was found to contain IL2. IL2 depletion from CSA resulted in a reduction in CFU-C colony proliferation. Addition of exogenous IL2 caused an increase in CFU-C colony numbers in a dose-dependent manner. This increase could be prevented by anti-Tac, a monoclonal antibody (MoAb) to the IL2 receptor. Moreover, anti-Tac in the absence of exogenous IL2 resulted in an overall decrease in colony numbers. Depletion of either adherent cells or T lymphocytes abolished the effect of IL2 and anti-Tac on colony growth. In the presence of IL2, re-addition of T lymphocytes to the T-depleted marrow or adherent cells to adherent cell-depleted marrow resulted in a significant increase in CFU-C colony numbers, whereas no significant effect was found when IL2-depleted CSA was used. Although T lymphocytes were not themselves essential for CFU-C colony growth, our studies indicate that IL2 and IL2-responsive T cells can regulate in vitro granulopoiesis.
mesh_terms: D000911:Antibodies, Monoclonal; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000502:physiology; D006098:Granulocytes / Q000502:physiology*; D006410:Hematopoiesis; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology*; D009000:Monocytes / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D003115:Colony-Stimulating Factors; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2