Certain myeloid cells possess receptors for interleukin-2.
A proportion of blasts from five of 10 cases of AML expressed receptors for IL-2 (IL-2R) when tested directly ex-vivo with monoclonal antibodies against the receptor. After in-vitro stimulation with various agents including TPA, gamma interferon and colony stimulating factor, the purified blast cells of all cases of AML tested (10 of 10) showed high levels (50-90% cells positive) of IL-2R expression. Granulocytic cells from the promyelocyte stage onwards lacked IL-2R both before and after in-vitro stimulation. In contrast, leukaemic promonocytes and normal peripheral monocytes expressed IL-2R both before and after stimulation. The receptors were detected with two different monoclonal antibodies (anti-Tac and 4H3--both IgG 2a antibodies) by indirect rosetting. In selected experiments, results were confirmed by fluorescence microscopy and by the APAAP technique. Normal monocytes possessed only small amounts of IL-2R since positivity was clearly detectable only by the indirect rosette assay. Irrelevant IgG 2a first-layer and second-layer-only controls were always negative. The endogenous nature of the IL-2 receptors was demonstrated by re-expression after capping and shedding. That the antigens detected were true IL-2R was confirmed by the fact that monoclonal antibody staining was blocked by recombinant IL-2. The restricted expression of IL-2R on early granulocytic and on monocytoid cells raises the possibility that IL-2 is important in the proliferation of these cell types.
D000954:Antigens, Surface / Q000032:analysis; D001853:Bone Marrow / Q000276:immunology; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D011971:Receptors, Immunologic / Q000032:analysis*; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000954:Antigens, Surface; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7