CD45RA(-)RO(-) (NAIVE) T-CELLS ROLL EFFICIENTLY ON E-SELECTIN AND P-SELECTIN AND VASCULAR CELL-ADHESION MOLECULE-1 UNDER FLOW() (MEMORY) BUT NOT CD45RA(+)RO()

This study examines the molecular mechanisms that underlie the observe d preferential interactions of memory vs naive T cells with activated vascular endothelium. Many more CD4(+) CD45RO(+) (memory) cells adhere d to 6-h TNF-alpha-activated human umbilical vein endothelium under fl ow than CD4(+)CD45RA(+) (naive) cells, Adhesion studies were performed using Chinese hamster ovary (CHO) cell monolayers expressing human E- or P-selectin (CHO-E and CHO-P, respectively) or with soluble vascula r cell adhesion molecule-1 (VCAM-1)-coated glass surfaces. Under flow at 1.8 dynes/cm(2), RO(+) T cells rolled extensively at low velocity o n both CHO-P and CHO-E monolayers and VCAM-1, whereas very few RA(+) T cells interacted with these surfaces. VCAM-1-dependent rolling was bl ocked completely by anti-very late Ag-4 (VLA-4) Abs, Purified CD4(+)RA (+) T cells could be converted to RO(+) cells by mitogen stimulation a nd 7-day culture in vitro, and this correlated with the acquisition of the ability to roll on E- or P-selectin, but not on VCAM-1 under flow . In summary, these data indicate that CD45RO(+) cells interact with E - and P-selectins and VCAM-1 much more effectively than do CD45RA(+) c ells under flow conditions, and these adhesion pathways may contribute , either individually or in combination, to the preferential recruitme nt of memory T cells to peripheral sites of inflammation.