Effects of rrSCF on multiple cytokine responsive HPP-CFC generated from SCA+Lin- murine hematopoietic progenitors.

We have previously defined a subset of High Proliferative Potential Colony Forming Cells (HPP-CFC), derived from murine marrow purified for early progenitors expressing the Stem Cell Antigen (SCA+) and lacking terminal lineage markers (Lin-), which are responsive to multiple cytokines in combination. Stem Cell Factor (SCF), a multipotent growth factor which is the ligand for c-kit, synergizes with these multiple factor combinations to increase colony number and size. SCF is thus a potent mitogen with direct action on early hematopoietic progenitor cells. These data are consistent with a model of stromal control of hematopoiesis via elaboration of multiple cytokines in locally high concentration, with SCF playing a central role.