[Viral interactions with the host's immune system].

Viruses are obligatory intracellular parasites, which differ in their structure and strategy of replication. The establishment of an antiviral state in uninfected cells and the elimination of virally infected cells are critical tasks in the host defence. Against the extensive array of immune modalities, viruses have successfully learned how to manipulate host immune control mechanisms. The study of viral strategies of immune evasion can provide insights into host-virus interactions and also illuminates essential functions of the immune system.