Immunosenescence of Natural Killer Cells, Inflammation, and Alzheimer’s Disease

Figure 1

Balance of inhibitory and activating signals in NK cell activation. Inhibitory signals are mediated through receptors specific for human leukocyte antigen (HLA) class I molecules and other inhibitory receptors such as PD-1 (ligand PD-1L) and TIGIT (ligands CD155 and CD112). Activating signals are transmitted though several surface receptors that recognize ligands expressed on transformed cells. The balance between inhibitory and activating signals will determine NK cell activation and function.