Liver sinusoidal endothelial cells have a capacity for inducing nonresponsiveness of T cells across major histocompatibility complex barriers.

Livers transplanted across major histocompatibility complex (MHC) barriers in mice are normally accepted without recipient immune suppression. To identify the cell type that contributes to induction of such a tolerance state, we established an allogeneic mixed hepatic constituent cell-lymphocyte reaction (MHLR) assay. Hepatic constituent cells were isolated from C57BL/6 (B6) and Balb/c mice as stimulators, and splenocytes were isolated from B6 mice as responders. Irradiated hepatic constituent cells were co-cultured with fluorescent dye (CFSE)-labeled B6 splenocytes. In the allogeneic MHLR using either whole hepatic constituent cells or parenchymal hepatocytes as stimulators, a lack of T-cell proliferation was observed. Only when CD105(+) cells, which are exclusively liver sinusoidal endothelial cells (LSECs), were depleted from hepatic constituent cell stimulators, the MHLR resulted in marked proliferation of both allo-reactive CD4(+) and CD8(+) T cells. These results indicate that CD105(+) LSECs have the capacity to induce nonresponsiveness of T cells across MHC barriers.