Role of Natural Killer and Gamma-Delta T cells in West Nile Virus Infection

Wang, Tian; Welte, Thomas

 T cells also play a role in memory T cell development during WNV infection. TCRδ −/− mice that survived primary WNV infection had a numeric and functional reduction in memory T cell responses. However,  T cells are not directly involved in the recall response to WNV infection. This is supported by the fact that depletion of these cells in WNV-infected mice does not affect host susceptibility to the secondary challenge [63] . In WNV-infected CR −− ï€ mice, splenic DCs had an impaired antigen-presenting capacity, and lower levels of CD40, CD80, CD86, and MHC class II expression and IL-12 production than did those of wild-type mice [64] . This suggests that the crosstalk between  T cells and DCs plays an important role in promoting DC maturation and T cell priming. A low level of WNV replication in  T cells induced pro-inflammatory cytokines, including IFN-, and TNF- (Table 1) . DCs co-cultured with WNV-infected  T cells also had enhanced levels of co-stimulatory molecules, MHC class II expression, and IL-12 production [64] . Thus, WNV-activated  T cells promote DC activation through direct contact with DCs and/or the secreting molecules induced upon infection.