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-surfac e receptors for the interleukins- 2, -4 and -7, and possibly others. W e studied its expression in cells and cell lines of myeloid origin and found ubiquitous presence of gamma(c), mRNA in all cells examined. Di fferential regulation of gamma(c) expression was observed in myeloid c ell lines induced to differentiate in vitro. In K-562 erythromyeloid c ells, a sharp rise in the levels of gamma(c) mRNA and protein accompan ied megakaryocytic, but not erythroid, differentiation. Surface bindin g of interleukin-2, as well as the transcripts for cognate receptor ch ains, were scarcely detectable in K-562 cells, whereas a significant i ncrease in the binding of granulocyte-macrophage colony-stimulating fa ctor specifically occurred during their megakaryocytic maturation. Our data indicate that expression of gamma(c) is a common feature of huma n myeloid cells, and suggest that its expression may be a requirement for human myelopoiesis.