ABSTRACT
<p><b>OBJECTIVE</b>The influence of the mimic hematopoietic microenvironment and adhesion factor on the initial divisional behavior of human cord blood hematopoietic progenitors was studied in the culture system with certain cytokines.</p><p><b>METHODS</b>(1) CD(34)(+) CD(38)(-) single cell was sorted by FACS. (2) The stem cell supporting stromal feeder layer AFT024 and single adhesive factor fibronectin (Fn) were used in the culture system and their influence on the initial division was observed.</p><p><b>RESULTS</b>(1) In the presence of the combined cytokines, the CD(34)(+) CD(38)(-) human cord blood cells displayed fixed fraction of quiescent, slow and fast division, and asymmetric division. (2) There was no influence of adhesive factor itself on initial division of CD(34)(+) CD(38)(-) cells. (3) The hematopoietic microenvironment mimicked by AFT024 promoted CD(34)(+) CD(38)(-) cells to proliferate extensively and undergo more asymmetric division.</p><p><b>CONCLUSIONS</b>(1) CD(34)(+) CD(38)(-) cells are heterogeneous and composed of various subpopulations with different initial proliferative behavior, including asymmetric division. (2) The hematopoietic microenvironmental mimicked by AFT024 supports the hematopoietic progenitors better than cytokines and single adhesion factor do, for their proliferation extensively and preservation the self-renewal capacity.</p>