Epigenetic modulation of host: new insights into immune evasion by viruses.

Viruses have evolved with their hosts, which include all living species. This has been partly responsible for the development of highly advanced immune systems in the hosts. However, viruses too have evolved ways to regulate and evade the host's immune defence. In addition to mutational mechanisms that viruses employ to mimic the host genome and undergo latency to evade the host's recognition of the pathogen, they have also developed epigenetic mechanisms by which they can render the host's immune responses inactive to their antigens. The epigenetic regulation of gene expression is intrinsically active inside the host and is involved in regulating gene expression and cellular differentiation. Viral immune evasion strategies are an area of major concern in modern biomedical research. Immune evasion strategies may involve interference with the host antigen presentation machinery or host immune gene expression capabilities, and viruses, in these manners, introduce and propagate infection. The aim of this review is to elucidate the various epigenetic changes that viruses are capable of bringing about in their host in order to enhance their own survivability and pathogenesis.