TNF-alpha controls intrahepatic T cell apoptosis and peripheral T cell numbers.
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-alpha. 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-alpha is responsible for inducing apoptosis in the liver and suggest that CD8(+) T cells escaping this mechanism of deletion can recirculate into the periphery.
David H. Smith Center for Vaccine Biology and Immunology, Aab Institute of Biomedical Sciences, University of Rochester, Rochester, NY 14642, USA.
Debbie A
DA
Murray
I Nicholas
IN
Crispe
D019264:Adoptive Transfer; D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D020287:In Situ Nick-End Labeling; D008099:Liver / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
D014409:Tumor Necrosis Factor-alpha