Deficiency in WDFY4 reduces the number of CD8 T cells via reactive oxygen species-induced apoptosis.

WDFY4 (WD repeat and FYVE domain-containing 4) is a susceptibility gene involved in several autoimmune diseases and plays an important role in the immune system. However, it is not clear how WDFY4 affects T cells. We have generated a Wdfy4-knockout mouse and found that selective deficiency of Wdfy4 in T cells led to a reduction in the number of CD8 T cells in the periphery, thus promoting tumor growth when mice were challenged with a transplantable tumor. Moreover, conditional ablation of Wdfy4 in T cells enhanced the apoptosis of CD8 T cells and increased the intracellular levels of reactive oxygen species accompanied by the upregulation of Nox2. Mechanistically, the decrease in the CD8 T-cell numbers in Wdfy4-knockout mice was associated with activation of the p53 pathway and inhibition of the extracellular signal-regulated kinase pathway. In addition, WDFY4 participated in cell proliferation. In conclusion, our results elucidate the biological role of WDFY4 in apoptosis and establish a link between WDFY4 and T cells.