Natural Killer Cells in Hepatitis C Virus Infection: From Innate Immunity to Adaptive Immunity
Section snippets
Natural Killer Receptor Expression and Effector Cell Functions
We initially examined NK cell responsiveness in chronic hepatitis C.9 NK cells isolated from peripheral blood were cocultured for 24 hours with either Hep3B hepatoma cells or K562 cells, a classic NK-sensitive target, and subjected to flow cytometric analysis for IFN-γ production. NK cells from patients with chronic hepatitis C (HCV-NK), on exposure to K562 cells, produced IFN-γ at levels similar to those of NK cells isolated from healthy donors (N-NK). In contrast, HCV-NK cells did not produce
Impact of Natural Killer Cells on Adaptive Immunity
Originally, the NK cell was thought to be just an effector cell for killing unwanted cells. However, recent research has been shedding light on its role as a regulator for the subsequent adaptive immune responses. For example, there have been reports that NK cells activated DCs via a tumor necrosis factor–α–dependent mechanism,11 and that NK cells down-regulated an immune response by killing immature DCs.12 Immature DCs distributed into the peripheral organs such as the liver undergo maturation
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