Regulatory T cells resist virus infection-induced apoptosis.

Journal of virology

PubMedID: 25473049

Che JW, Kraft AR, Selin LK, Welsh RM. Regulatory T cells resist virus infection-induced apoptosis. J Virol. 2014;.
Regulatory T (Treg) cells are important in the maintenance of self-tolerance, and the depletion of Treg cells correlates with autoimmune development. It has been shown that IFNaƟ responses induced early in the infection of mice can drive memory (CD44hi) CD8 and CD4 T cells into apoptosis, and we questioned here whether the apoptosis of CD44-expressing Treg cells might be involved in the infection-associated autoimmune development. Instead, we found that Treg cells were much more resistant to apoptosis than CD44hi CD8 and CD4 T cells at day 2-3 after lymphocytic choriomeningitis virus infection, when type I IFN levels are high. The infection caused a down-regulation of the IL-7 receptor, needed for survival of conventional T cells, while increasing on Treg cell the expression of high affinity IL-2 receptor, needed for STAT5-dependent survival of Treg cells. The stably maintained Treg cells early during infection may explain the relatively low incidence of autoimmune manifestations among infected patients.IMPORTANCE
Autoimmune diseases are controlled in part by regulatory T cells (Treg) and are thought to sometimes be initiated by viral infections. We tested the hypothesis that Treg may die off at early stages of infection, when virus-induced factors kill other lymphocyte types. Instead we found that Treg resisted this cell death, perhaps reducing the tendency of viral infections to cause immune dysfunction and induce autoimmunity.