Tumor necrosis factor and interferon: cytokines in harmony

Individually, tumor necrosis factor (TNF) and the various interferons frequently display strong antiviral activities. Certain combinations of these cytokines, however, induce a synergistic antiviral state which is distinct from that induced by either one alone. This novel synergistic antiviral state likely occurs through several possible mechanisms, involves multiple signaling pathways, and inhibits a wider range of viruses than the individual cytokines alone. While underappreciated when first discovered, this synergistic phenomenon is proving to be of a much broader scope than initially thought. More work is needed to refine our understanding of this observation and its physiological implications for anti-pathogen responses.