PECAM-1: its expression and function as a cell adhesion molecule on hemopoietic and endothelial cells

PECAM-1, the platelet-endothelial cell adhesion molecule, is expressed on a variety of mature hemopoietic cell types (including neutrophils, monocytes and T cell subsets) and is also present on endothelia. In such cases, this glycoprotein functions as either a homotypic or heterotypic adhesion molecule contributing to cell migration, inflammatory processes and wound healing. We have recently shown that PECAM-1 is expressed on a variety of hemopoietic progenitor cell types and on stromal macrophages from human bone marrow. In this review, we discuss the possible functional significance of this molecule for both hemopoietic cell differentiation and for mature cells.