The role of human endothelial cells in allograft rejection. Some in vitro correlates.

Endothelial cells, separated from the inside of the umbilical vein by collagenase digestion, could clearly stimulate allogeneic lymphocytes to blastogenesis and increased DNA synthesis in mixed lymphocyte endothelial-cell cultures. Many of the characteristics of these mixed cultures were similar to those found in mixed cultures consisting exclusively of allogeneic lymphoid cells; the MLC response. Endothelial cells could also be destroyed in vitro by cells sensitized in mixed lymphocyte cultures. When incubated in the presence of specific HL-A antisera, they were destroyed in non-immune peripheral blood mononuclear cells. These three reactions are thought to be in vitro correlated to some of the events taking place following allografting in vivo.