NK cells and interferons

The role of Natural Killer cells in host defense against infections as well as in tumour surveillance has been widely appreciated for a number of years. Upon recognition of altered cells, NK cells release the content of cytolytic granules, leading to the death of target cells. Moreover, NK cells are powerful producers of chemokines and cytokines, particularly Interferon-gamma (IFN-gamma), of which they are the earliest source upon a variety of infections. Despite being armed to fight against pathogens, NM cells become fully functional upon an initial phase of activation that requires the action of several cytokines, including type I IFNs. Type I IFNs are now recognized as key players in antiviral defense and immune regulation, and evidences from both mouse models of disease and in vitro studies support the existence of an alliance between type I IFNs and NM cells to ensure effective protection against viral infections. This review will focus on the role of type I IFNs in regulating NM cell functions to elicit antiviral response and on NM cell-produced IFN-gamma beneficial and pathological effects. (C) 2014 Elsevier Ltd. All rights reserved.