Interferons: in the out of the net

RESUMO

Cytokines are soluble polypeptides whose primary function is signalling from cell to cell. Within the immune system, cytokines function in a complex network, and are responsible for proper development and differentiation of cells and organs, as well as for controlling the humoral and cellular responses. Interferons (IFNs), best known for their antiviral activity, are cytokines that can modulate various functions of the immune system. In this review some aspects of the interactions between IFNs and other cytokines will be presented. In considering IFNs in the net, we will discuss their interations with other cytokines as well as the role of the transcription factor IRF-1 as a candidate for linking the cytokine network. To understand the immune system having IFNs out of the net, we have generated some "knock-out"mice deleted for specific components of the interferon system. These animals proved to be an important tool to clarify the role of these cytokines in the mechanism of defense and development of the immune system.