Mouse cytomegalovirus encoded immunoevasins and evolution of Ly49 receptors - Sidekicks or enemies?

- Cytomegaloviruses developed many immune evasion mechanisms to avoid host NK cells.
- Host in turn employed many strategies to cope with CMV infection.
- Ly49 receptors recognize MHC I or MHC I-like proteins.
- Cytomegalovirus interferes with inhibitory and activating Ly49 receptors.
- Viral interference with Ly49 receptors modulates NK cell function.

Cytomegaloviruses (CMVs) have dedicated a large portion of their genome towards immune evasion targeting many aspects of the host immune system, particularly NK cells. However, the host managed to cope with the infection by developing multiple mechanisms to recognize viral threat and counterattack it, thus illustrating never-ending evolutionary interplay between CMV and its host. In this review, we will focus on several mechanisms of NK cell evasion by mouse CMV (MCMV), the role of host inhibitory and activating Ly49 receptors involved in the virus control and acquisition of adaptive features by NK cells as a consequence of MCMV infection.