[Adhesion of lymphocytes to allogenic endothelium. Four different pathways].

Lymphocyte adhesion to allogeneic endothelium is a critical step in graft rejection. To further characterize the expression and the regulation of adhesion molecules involved in this process, we stimulated endothelial cells with Interleukin 4 or tumor necrosis factor alpha (TNF alpha) and blocked lymphocyte adhesion to stimulated-endothelial cells with monoclonal antibodies. We demonstrated that lymphocytes bound endothelial cells by at least four adhesion pathways: a) a LFA 1/ICAM 1 dependent pathway on TNF alpha-stimulated endothelial cells, b) a LFA 1 dependent/ICAM 1 independent pathway on unstimulated or IL 4-stimulated endothelial cells, c) a VLA 4/VCAM 1 dependent pathway on unstimulated and stimulated-endothelial cells, d) a CD 2 dependent/LFA 3 independent pathway on IL 4 and TNF alpha-stimulated endothelial cells.