For JEV, it has been reported that blockage of CD137 (also called 4-1BB and TNFRSF9), a costimulatory molecule expressed on MΦs, DCs, NK cells, T cells, and B cells, makes C57BL/6 mice less susceptible to infection, by enhancing the innate immune responses involving the rapid activation of type I/II IFN responses and the increased infiltration of mature Ly6Chi monocytes into the inflamed CNS [223]. This evidence concerns the gene TNFRSF9 and infection.