Interleukin-3 Is a Differentiation Factor for Human Basophils

Abstract

AbstractThe effect of recombinant human (rh) cytokines, interleu-kin-1 a (IL-1α), interleukin-2 (IL-2), interleukin-3 (IL-3), interleukin-4 (IL-4), granulocyte/macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), monocyte/macrophage colony stimulating factor (M-CSF), interferon-a (IF-α), interferon-γ (IF-7), and the tumor necrosis factor-a (TNF-α) on differentiation and function of metachromatic cells (MCS) was studied. Among all cytokines tested, rh interleukin-3 (rhlL-3) selectively induced a significant formation of MCS (IL-3: 1.1 ± 0.6 x 105v control: 0.02 ± 0.15 x 105 MCS/mL suspension) and dose dependent increase in formation of intracellular histamine (IL-3, 100 U/mL: 95 ± 23 ng/mL v control: 1.8 ± 0.8 ng/mL) in a bone marrow suspension culture system (analyzed on day 14 of culture). Besides MCS, formation of eosinophils was observed in this culture system in the continuous presence of rhlL-3, whereas IL-3 pulse-stimulation for three hours and subsequent exposure to control medium induced growth of MCS but not of eosinophils. By combined immunofluorescence/toluidine blue staining, MCS were found to express a cell surface marker profile that corresponds to the immunological phenotype of peripheral blood basophils (MY-7(CD13) + , VIM12(CD11b)+, VIM2+, MAX1- , MAX24- and YB5B8- ). Furthermore, cultured MCS expressed surface membrane receptors for IgE and could be triggered for nontoxic histamine release by a monoclonal anti-lgE antibody. To evaluate a possible influence of IL-3 on basophil function, studies were extended to freshly obtained blood basophils (healthy volunteers, n = 3). However, like all other cyto-kines tested, rhlL-3 failed to induce basophil histamine release. Taken together, our studies demonstrate that IL-3 is a differentiation factor for human basophils.© 1989 by Grune & Stratton. Inc. 0006-4971/89/7307-0137$3.00/0