Harnessing Natural Killer Cell-Mediated Innate Immune Responses for Cancer Treatment: Advances and Challenges

antigen-1, etc .) and inhibitory signals (NKG2A, killer cell lectin-like receptor G1, and T-cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT), etc .) that originate from abnormal cells and the microenvironment. 7 In addition to activating and inhibitory receptors, co-stimulatory receptors or adhesion molecules (2B4, CD27, CD28, CD226 etc .) 8–11 can induce NK cell function. NK cells induce apoptosis of the target cell via tumor necrosis factor (TNF)- related apoptosis-inducing ligand and Fas ligand, and by directly releasing lytic granules such as perforin and granzyme-B. 12,13 Another mechanism of NK-mediated killing is antibody-dependent