Interferons and viral infections

Interferons represent a family of cytokines, which is of central importance,,in the inn,ate immune response to virus infections. All interferons act-as secreted ligands of specific cell surface receptors, eliciting the transcription-of hundreds of interferon-stimulated genes whose protein products have antiviral activity, as well As antimicrobial,antiproliferative/antitumor, and immunombdulatory effects. Expression of type I and III interferons in induced in virtually all cell types upon recognition of. viral. molecular patterns,. especially nucleic acids, by cytoplasmic, and, endosomal, receptors, whereas type II interferon is induced by cytokines such as IL-12 and its expression is restricted to immune cells such as T cells and NK cells. The effectiveness of the interferon system in counteracting viral infections is reflected by the multitude of inhibitors of interferon induction or interferon action that are encoded by many viruses, preventing their eradication and resulting in the continued coexistence of viruses and. vertebrates., The unique biological. functions of interferons have led to their therapeutic use in the treatment of diseases such as hepatitis multiple sclerosis and certain leukemias. (C) 2009 International,Union. of Biochemistry and Molecular Biology, Inc. Volume 35, Number 1, January/February2009, Pages 14-20. E-mail: seng@ccf.org