THE LIVER ELIMINATES T-CELLS UNDERGOING ANTIGEN-TRIGGERED APOPTOSIS IN-VIVO

Deletion of mature peripheral T cells may result from TCR ligation by bacterial enterotoxins, endogenous provirus-encoded superantigens, and peptide antigens. But the ultimate fate of deleted T cells is not cle ar. Using a line of T cell receptor transgenic mice injected with anti genic peptide, we have documented that peripheral deletion is accompan ied by the induction of abortive T cell activation followed by the dis appearance of transgene-positive T cells. As these T cells disappear f rom the lymph nodes and spleen, they accumulate in the liver, where th ey undergo apoptosis. This is likely to be a general clearance pathway for T cells that are programmed to undergo apoptosis in vivo, and it may further explain the expansion of the intrahepatic T cell pool in m ice with genetic defects in the T cell apoptosis mechanism, such as th e for mutant.