Microbial Subversion of NK Cell Function
Stipan Jonjic and Ulrich Kosinowski
from: Microbial Subversion of Immunity: Current Topics (Edited by: Peter J. Lachmann and M.B.A. Oldstone). Caister Academic Press, U.K. (2006)
Natural killer (NK) cells play a crucial role in the resistance to several viruses and other intracellular pathogens. They are among the first cells to sense the release of proinflammatory cytokines, as well as the perturbations in the expression of MHC class I molecules and other surface molecules induced by microbial invasion of cells. One of the best illustrations of the importance of NK cells is represented by the various microbial functions evolved to counter NK cell response. Here we summarize the major mechanisms and receptors that NK cells can employ to positively recognize and kill virus-infected cells and the range of microbial strategies that reduce the efficacy of NK cell activation and their effector functions. The elements for viral NK cell- subversions are mainly based on the assumption deriving from numerous findings in readily controlled in vitro systems whereas the evidence for their relevance in vivo are still only fragmentary. The murine model of cytomegalovirus infection highlights the biological importance of these viral immunoevasins. The analysis of the viral proteins will continue to provide important details on the diversity of mechanisms by which NK cells can be activated and modulated read more ...