Abstract

Human endothelial cells were obtained by collagenase digestion of the umbilical vein wall, explanted into tissue culture, and grown as monolayers of cells. Endothelial cells extracted from these monolayers were specifically lysed by anti-HLA-DR alloantisera. Moreover, the stimulating capacity of these endothelial cells toward allogeneic peripheral blood mononuclear lymphocytes was specifically and significantly inhibited by the presence of relevant anti-HLA-DR antisera. Endothelial cells that expressed HLA-DR determinants were also capable of substituting for macrophages in the lymphoproliferative response of purified T cells to soluble protein antigens. Moreover, in concordance with the results previously reported in which macrophages were employed, the endothelial cell donor should share HLA-DR determinants with the T cell donor for an optimal response to occur.