LY6E and viral infectious disease: To further confirm the role of LY6E in HCoV-OC43 infection, we showed that while reducing the expression of LY6E in HepG2 cells by shRNA knockdown significantly increased the viral RNA in HCoV-OC43-infected cells by 10- to 20-fold (Fig. 5A and B), ectopic expression of LY6E in C3A (Fig. 5C and D) or A549 (Fig. 5E and F) cells reduced their susceptibility to the virus infection by approximately 10-fold.