T-CELLS BIND TO THE ENDOTHELIAL ADHESION MOLECULE GMP-140 (P-SELECTIN)

A crucial step in an effective immune response is the adhesion of circ ulating lymphocytes. Lymphocytes must attach to endothelial cells befo re they can migrate into the graft. It has been shown that T cells bin d to ICAM-1 and VCAM-1. Additionally, certain T cell subsets bind to E LAM-1. We now report that resting CD4(+) and CD8(+) T cells as well as individual CD4(+) T cell clones and CD8(+) T cell lines bind to GMP-1 40 in an adhesion assay using protein chimeras consisting of the extra cellular domain of GMP-140 linked to the hinge domain of human IgG1. W hereas resting T cells bound similarly to ELAM-1 IgG and GMP-140 IgG, activated T cells represented by CD4(+) T cell clones and CD8(+) T cel l lines bound to GMP-140 IgG, but not to ELAM-1 IgG. Neither the bindi ng to immobilized GMP-140 IgG, nor to immobilized ELAM-1 IgG could pro vide T cells with costimulatory signals for proliferation in the prese nce of submitogenic concentrations of anti-CD3 antibodies. The binding of T cells to the endothelial adhesion receptor GMP-140 might be impo rtant during the initial adhesion process of lymphocytes in rejecting grafts.