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Natural killer cells: multifaceted players with key roles in hepatitis C immunity
Author(s) -
GoldenMason Lucy,
Rosen Hugo R.
Publication year - 2013
Publication title -
immunological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.839
H-Index - 223
eISSN - 1600-065X
pISSN - 0105-2896
DOI - 10.1111/imr.12090
Subject(s) - immunology , biology , interleukin 12 , lymphokine activated killer cell , interleukin 21 , interferon , natural killer cell , priming (agriculture) , hepatitis c , immune system , t cell , cytotoxicity , cytotoxic t cell , in vitro , biochemistry , botany , germination
Summary Natural killer cells ( NK s) are involved in every stage of hepatitis C viral ( HCV ) infection, from protection against HCV acquisition and resolution in the acute phase to treatment‐induced clearance. In addition to their direct antiviral actions, NK s are involved in the induction and priming of appropriate downstream T‐cell responses. In the setting of chronic HCV , overall NK cell levels are decreased, subset distribution is altered, and changes in NK receptor ( NKR ) expression have been demonstrated, although the contribution of individual NKR s to viral clearance or persistence remains to be clarified. Enhanced NK cell cytotoxicity accompanied by insufficient interferon‐γ production may promote liver damage in the setting of chronic infection. Treatment‐induced clearance is associated with activation of NK cells, and it will be of interest to monitor NK cell responses to triple therapy. Activated NK cells also have anti‐fibrotic properties, and the same hepatic NK cell populations that are actively involved in control of HCV may also be involved in control of HCV ‐associated liver damage. We still have much to learn, in particular: how do liver‐derived NK s influence the outcome of HCV infection? Do NK receptors recognize HCV ‐specific components? And, are HCV ‐specific memory NK populations generated?