Fig. 2.

Diagram representing viral strategies of evading NCR-mediated recognition. The NK cell (top) expresses NCRs, which would normally recognize NCR ligands (cellular and pathogen-derived) on the infected cell (bottom). However, viruses evade this detection through the downregulation of cellular NCR ligands; through expression of inhibitory NCR ligands; through degradation of NCR-associated adaptor molecules; and possibly through the downregulation of the NCRs themselves. Viral proteins are depicted in green. Speculative viral immune-evasion mechanisms are indicated by a question mark next to the virus name [20, 22, 34, 57, 64, 65, 68]