[The role of canine hepatic sinusoidal lining cells in the immune response: analysis by mixed lymphocytes-sinusoidal lining cells culture].

The ability of canine sinusoidal endothelial cells (SEC) and Kupffer cells (KC) to function in several in vitro immunologic systems was investigated. Isolated sinusoidal lining cells (SLC) from canine liver were separated by centrifugal elutriation into structurally intact SEC and KC fraction with purities of 65% and 78%, respectively. In this study, it has been demonstrated that SEC and KC are found to be potent stimulators of mixed lymphocyte culture and they are capable of functioning as accessory cells for the activation of mitogen induced T cell. OKIal positive cells constituted 76.2% of SEC and 15.7% of KC. These Ia positive cells played an important role as stimulators in those responses, since the stimulating activity of both cells was lost by pretreatment with anti-Ia monoclonal antibody (OKIal) plus complement. In addition, lymphocytes stimulated with SEC and KC were cytotoxic for PHA blasts of the stimulator dogs. But lysis of autologous or third party allogeneic targets was virtually absent or low. These results indicate that SEC and KC stimulate allogeneic lymphocytes and the efferent phase of cell mediated cytotoxicity is induced by these cells. So SLC, especially SEC and KC, may play an important role in liver allograft rejection.