ANALYSIS OF AN INITIAL STEP OF T-CELL ADHESION TO ENDOTHELIAL MONOLAYERS UNDER FLOW CONDITIONS

We analyzed an initial step of T cell adhesion to endothelial cells un der flow conditions. An initial step in T cell-endothelial cell intera ctions was characterized either by a rolling phase, or by an immediate arrest without rolling. Anti-E- and P-selectin Abs inhibited T cell r olling on endothelial cells under flow conditions. The rolling velocit y of T cells on endothelial cells increased after treatment of endothe lial cells with anti-E- or P-selectin Abs. Also, rolling of T cells wa s observed on E-selectin-transfected CHO cells but not on ICAM-1-trans fected CHO cells. Thus, rolling of T cells under flow condition was de pendent on E-selectin as well as P-selectin expressed on endothelial c ells. In contrast, neither anti-E- nor P-selectin Abs inhibited the im mediate arrest of T cells on endothelial cells significantly and anti- ICAM-1 Abs also failed to inhibit the immediate arrest of T cells. The refore, other adhesion molecules may play an important role in the imm ediate arrest of T cells under flow conditions. The number of CD45RA(- ) T cells rolling on E-selectin-transfected CHO cells was much higher than that of CD45RA(+) T cells.