DIFFERENTIAL REGULATION OF THE EXPRESSION OF INTERLEUKIN-2 RECEPTOR GAMMA-CHAIN DURING THE IN-VITRO DIFFERENTIATION OF HUMAN MYELOID CELLS

The common gamma-chain (gamma(c)) is a shared component of cell-surface receptors for the interleukins- 2, -4 and -7, and possibly others. We studied its expression in cells and cell lines of myeloid origin and found ubiquitous presence of gamma(c), mRNA in all cells examined. Differential regulation of gamma(c) expression was observed in myeloid cell lines induced to differentiate in vitro. In K-562 erythromyeloid cells, a sharp rise in the levels of gamma(c) mRNA and protein accompanied megakaryocytic, but not erythroid, differentiation. Surface binding of interleukin-2, as well as the transcripts for cognate receptor chains, were scarcely detectable in K-562 cells, whereas a significant increase in the binding of granulocyte-macrophage colony-stimulating factor specifically occurred during their megakaryocytic maturation. Our data indicate that expression of gamma(c) is a common feature of human myeloid cells, and suggest that its expression may be a requirement for human myelopoiesis.