Myeloid and Erythroid Progenitor Cells From Normal Bone Marrow Adhere To Collagen Type

One of the mechanisms by which normal hematopoietic progenitor cells remain localized within the bone marrow microenvironment is likely to involve adhesion of these cells to extracellular matrix (ECM) proteins. For example, there is evidence that uncommitted, HLA-DR-negative progenitor cells and committed erythroid precursors (BFU-E) bind to fibronectin. However, fibronectin is not known to mediate binding of committed myeloid (granulocyte-macrophage) progenitors, raising the possibility that other ECM proteins may be involved in this process. We investigated the binding of the M07 myeloid cell line to a variety of ECM proteins and observed significant specific binding to collagen type I (56% 2 5%). minimal binding to fibronectin (18% k 4%) or to laminin (19% 2 5%). and no binding to collagen type 111, IV, or V. Similarly, normal bone marrow myeloid progenitor cells (CFU-GM) demonstrated significant specific binding to collagen type I(46% f 8% and 47% f 12% for day 7 CFU-GM and day 14 CFU-GM, respectively). The ability of collagen to