LYMPHOKINE REQUIREMENT FOR THE GENERATION OF NATURAL-KILLER-CELLS FROM CD34(+) HEMATOPOIETIC PROGENITOR CELLS

We have established a cell culture system without stromal cells that allows the CD34(+) hematopoietic progenitor cells (HPC) to differentiate into natural killer (NK) cells. CD34(+)Lin (CD3, CD16, CD56)(-) cells were purified using fluorescence-activated cell sorting from normal adult bone marrow (BM) and cultured for 28 days in medium supplemented with interteukin-2 (IL-2) and stem cell factor (SCF). NK (CD3(-)CD16(-)CD56(+)) cells were generated in a dose-dependent manner in response to SCF. NK cells originated from CD34(+)CD33(+)Lin(-)cells, but they were barely detectable in cultures of CD34(+)CD33(-)Lin(-) cells. However, on addition of IL-3, an induced differentiation of NK cells from CD34(+)CD33(-)Lin(-) cells was observed, although at a lower frequency, Supplementing of the cell cultures with SCF alone or both SCF and IL-3 for the first 7 days followed by IL-2 for the next 21 days is essential for production of NK cells from CD34(+)CD33(+)Lin(-)cells and from CD34(+)CD33(-)Lin(-) cells, respectively. These data provide direct evidence that NK cells arise from CD34(+)HPC and show the minimum lymphokine requirement for their differentiation. (C) 1995 by The American Society of Hematology.