Due to the key regulatory role of NKG2D or PD-1 and its ligands in the defense against virus infection, it is an important research route to determine whether EV71 affects the expression of NKG2DL or PD-L1 on IECs and contributes to evading iNK and CD3+iIELs lysis. Here, KLRK1 is linked to viral infectious disease.