Figure 2.

Generation of natural killer (NK) cell memory during murine cytomegalovirus (MCMV) infection. During MCMV infection, NK cells recognize MCMV-infected cells via Ly49H-m157 interactions, and Ly49H⁺ NK cells undergo clonal-like expansion, partially driven by the signal mediated by the costimulatory molecule DNAM-1 and pro-inflammatory cytokines, such as IL-12, IL-18, and IL-33. Following NK cell expansion, Ly49H⁺ NK cells enter a contraction phase that is dependent on the proapoptotic factor Bim and subsequently become long-lived memory NK cells. Autophagy, DNAM-1, and IL-12 are important for the generation of memory NK cells, whereas their survival is dependent on IL-15 [adapted from Ref. (19) with permission from Nature Publishing Group].