Natural Killer Cell Function and Dysfunction in Hepatitis C Virus Infection

Figure 1

Natural killer cell natural cytotoxicity. NK cell inhibitory receptors recognize “self” MHC-I molecules which can prevent cytolysis of healthy cells even when activating receptors interact with their ligands. Transformed or virus-infected cells often reduce MHC-I expression; thus when a NK cell activating receptor engages its ligand, there is no negative signal to overcome the positive activating signal and the target cell is destroyed through a perforin and granzyme apoptosis-inducing mechanism.