ANALYSIS OF INITIAL ATTACHMENT OF B-CELLS TO ENDOTHELIAL-CELLS UNDER FLOW CONDITIONS

This study examined the adhesive interactions of peripheral blood B ce lls with TNF-alpha-activated endothelial monolayers, and analyzed the roles of E-selectin, P-selectin, or VCAM-1 molecules expressed on acti vated HUVEC. B cell interaction occurred on activated HUVEC, but not o n resting HUVEC under flow conditions. the majority of peripheral bloo d B cells expressed P-selectin glycoprotein ligand-1 and alpha(4) inte grin. However, the expression of cutaneous lymphocyte Ag on B cells wa s low. Under flow conditions, B cells could bind to P-selectin-coated tubes and VCAM-1-transfected Chinese hamster ovary cells. In contrast, B cells could not bind to E-selectin-coated tubes. Adhesion activity of B cells to P-selectin-coated tubes was weaker than that of T cells. Furthermore, adhesion activity of B cells to VCAM-1-transfected Chine se hamster ovary cells was similar to that of T cells. Treatment of ac tivated HUVEC with anti-VCAM-1 mAb reduced interaction of B cells unde r flow conditions. However, the treatment of activated HUVEC with anti -P-selectin mAb did not reduce interaction. These data indicated that the interaction of VCAM-1 with alpha(4) integrin plays a major role in an initial attachment of B cells to endothelial monolayers under flow conditions.