Ubiquitin A 20 maintains activation-induced CD 4 + T cell death

Aberrant T helper (Th)2 polarization plays a critical role in allergic diseases; the underlying mechanism is to be further investigated. Ubiquitin E3 ligase A20 (A20) plays an important role in the immune regulation. This study aims to test a hypothesis that A20 plays an important role in the activation-induced cell death (AICD) in CD4+ T cells. In this study, a T cell AICD cell culture model was developed. T cell apoptosis was assessed by flow cytometry used as the indicator of AICD. A food allergy (FA) mouse model was developed. The results showed that the frequency of AICD CD4+ T cells was significantly less in FA mice as compared to control mice. Much less A20 expression was detected in CD4+ T cells in FA mice than in control mice. Interaction of TIM1 (T cell immunoglobulin mucin domain-1) and TIM4 suppressed the expression of A20 in CD4+ T cells. Overexpression of A20 promoted the AICD in CD4+ T cells. In conclusion, A20 plays a critical role in the T cell AICD. To promote A20 expression can be a potential remedy in the regulation of T cell AICD.