Cytokine and cytokine receptor genes 'captured' by viruses.

Viruses have historically been used as tools to understand basic cellular functions. Recently viruses have been shown to encode genes whose protein products function to modulate the host immune system. Viral immune modulators can now be exploited for the purpose of further understanding cellular immune phenomena. These studies promise to provide a rich source of information for the cellular immunologist, the basic virologist, and the clinic.