TNF-α Controls Intrahepatic T Cell Apoptosis and Peripheral T Cell Numbers

Abstract

At the end of an immune response, activated lymphocyte populations contract, leaving only a small memory population. The deletion of CD8+ T cells from the periphery is associated with an accumulation of CD8+ T cells in the liver, resulting in both CD8+ T cell apoptosis and liver damage. After adoptive transfer and in vivo activation of TCR transgenic CD8+ T cells, an increased number of activated CD8+ T cells was observed in the lymph nodes, spleen, and liver of mice treated with anti-TNF-α. However, caspase activity was decreased only in CD8+ T cells in the liver, not in those in the lymphoid organs. These results indicate that TNF-α is responsible for inducing apoptosis in the liver and suggest that CD8+ T cells escaping this mechanism of deletion can recirculate into the periphery.