An ICAM-1 like cell adhesion molecule is responsible for CD34 positive haemopoietic stem cells adhesion to bone-marrow stroma.

The microenvironment in the haematopoietic organs plays an important role in regulating and sustaining differentiation and self-renewal of haematopoietic stem cells. Although crucial for stem cell maintenance and homing, the stromal cell-stem cell interactions are poorly understood. Here we show that an ICAM-like molecule is responsible for stem cell adhesion to stromal cells in vitro. The molecule was characterized by a monoclonal antibody 3E10. Immunoblotting results indicated that the molecule had an electrophoretic mobility equal to that of intercellular cell adhesion molecule-1 (ICAM-1). Binding inhibition assays, however, showed that inhibition of binding of enriched CD34 cells by 3E10 was more prominent in comparison with that of ICAM-1.