The function of type I interferons in antimicrobial immunity

Type I interferons (IFN-a and IFN-P) were originally described as potent an tiviral substances, which are produced upon infection of animal cells with viruses. Despite a large body of literature that has accumulated during the past 25 years, their regulatory function in the immune system is still muc h less appreciated. Recent studies have highlighted the production of type I IFNs, their function in the immune response to infectious agents and the target cells of these interferons. Type IIFNs clearly affect the release of proinflammatory cytokines or nitric oxide by dendritic cells and macrophag es, the capacity of type II interferon (IFN-gamma) to activate phagocytes, the differentiation of T helper cells and the innate control of non-viral p athogens.