P-selectin and vascular cell adhesion molecule 1 mediate rolling and arrest, respectively, of CD4+ T lymphocytes on tumor necrosis factor alpha-activated vascular endothelium under flow

This report examines the adhesive interactions of human CD4+ T lymphocytes with tumor necrosis factor alpha-activated human endothelial cell monolayers in an in vitro model that mimics microcirculatory flow conditions. Resting CD4+ T cell interactions with activated endothelium consisted of initial attachment followed by rolling, stable arrest, and then spreading and transendothelial migration. P-selectin, but not E-, or L-selectin, mediated most of this initial contact and rolling, whereas beta 1-integrins (alpha 4 beta 1), interacting with endothelial-expressed vascular cell adhesion molecule 1, participated in rolling and mediated stable arrest. In contrast, beta 2-integrins were primarily involved in spreading and transmigration. These findings highlight an important role for P- selectin and suggest discrete functions for beta 1- and beta 2- integrins during lymphocyte recruitment to sites of immune-mediated inflammation.