EXPRESSION OF ADHESION MOLECULES ON HUMAN HEMATOPOIETIC PROGENITOR CELLS AT DIFFERENT MATURATIONAL STAGES

In this report we examined the expression of several adhesion molecules on human hematopoietic progenitor cells at different maturational stages. Human hematopoietic progenitor cell-enriched fractions were prepared from bone marrow cells by depleting lymphocytes and monocytes (CD2+, CD14+ and CD19+ cells). These cells were separated into adhesion molecule-positive and -negative cell populations by immunomagnetic separation methods and then assessed for their ability to form various colony forming cells (CFC). CD44 and CD49d were expressed on multipotent hematopoietic progenitor cells, or mixed colony forming units (CFU-Mix), erythroid burst forming units (BFU-E), granulocyte-macrophage CFU (CFU-GM) and erythroid CFU (CFU-E). Leu8 was expressed on CFU-Mix, BFU-E and some populations of CFU-GM, but not CFU-E. CD11a was expressed on some populations of CFU-Mix, CFU-GM and BFU-E. CD54 was expressed only on some populations of CFU-GM. These results suggest that Leu8, CD44, CD49d and CD11a appear to play important roles in the differentiation and proliferation of human hematopoietic progenitor cells at different maturational stages in the bone marrow microenvironment.