[Virokines and viroceptors--viral immunomodulators with clinical and therapeutic implications]

During evolution viruses have developed variety of sophisticated strategies for interactions with the immune system of the host. One of the defense strategies that counteract the immune responses of the infected organism exploits viral proteins that directly interfere with the host's cytokine system. Among such immunomodulatory molecules are classed also viral homologs of cytokines (virokines) and viral homologs of cytokine receptors (viroceptors), produced and secreted by the virus-infected cell. Virokines and viroceptors are encoded by large DNA viruses--herpesviruses and poxviruses. The respective genes have been obviously "stolen" by viruses from the host genomes and then have been modified. Detailed characterization of these viral elements, which induce or subvert the host's cytokine responses against viral infection, may contribute to a better understanding of the mechanisms which help the viruses to escape immune surveillance. Such knowledge have potential implications for viral epidemiology, treatment or prevention of viral and inflammatory diseases, and for the development of safer vaccines. Examples of viruses indicate, that "capturing" of the immunomodulatory genes may be a more general strategy used also by other types of pathogenic or parasitic organisms to evade the immune responses of their hosts. (Tab. 2, Fig. 2, Ref. 73.)