Blast colony-forming cells and precursors of colony-forming cells detectable in long-term marrow culture express the same phenotype (CD33- CD34+)

Abstract

We have previously shown that CD33- CD34+ human marrow cells are capable of giving rise to colony-forming cells (CFC) in long-term marrow culture (LTMC) but are mainly depleted of progenitors that directly form colonies in semi-solid media. In contrast, the CD33+ CD34+ population contains most of the CFC but not the precursors of these cells detectable in LTMC. The purpose of the present study was to determine if a form of CFC with self-renewal potential, the blast CFC, is contained within the CD33+ CD34+ or CD33- CD34+ population. The results demonstrate that blast CFC segregate within the CD33- population, representing a distinct progenitor population that may be analogous to progenitors for CFC detectable in LTMC.