Development of natural killer cells, B lymphocytes, macrophages, and mast cells from single hematopoietic progenitors in culture of murine fetal liver cells

We have recently established a clonal culture system that supports the growth of immature natural killer (NK) cells from murine fetal thymocytes. We now describe a culture system for mixed NK cell colony formation from single lymphohematopoietic progenitors, When Sca-1(+)c-kit(+) fetal liver cells were cultured in methylcellulose media with interleukin (IL)-2, IL-7, IL-11, and steel factor (SF), we found mixed colonies consisting of diffuse small round cells characteristic of immature NK cells and other types of cells. The single cell origin of the mixed colonies was established by micromanipulation, Individual mixed colonies derived from single cells were characterized by flow cytometric analysis and May-Grunwald Giemsa staining. All mixed colonies contained Thy-1(+)B220(-) cells, which can differentiate to mature NK cells in fetal thymus organ culture. Most of the colonies contained B220(+) B-lineage cells and macrophages, and some contained mast cells. IL-1 alpha and IL-3, which have previously been shown to inhibit the T- and B-cell potentials of blast colonies, suppressed the formation of mixed NK cell colonies, The clonal culture assay presented here may be useful in analysis of the developmental pathway and commitment of NK cells from multipotential progenitors. (C) 1997 by The American Society of Hematology.