Infection with HCMV US19stop led to evasion from NK cell mediated killing, as the infected cells were hardly killed (Fig. 6A).We think that the reduced killing of US19Stop-infected cells is because HCMV uses many mechanisms to evade recognition by NK cells8, including the US18 and US20-mediated downregulation of B7-H6 that we show here. This evidence concerns the gene NCR3LG1 and infection.