Fig. 2: Themis2 negatively regulates the memory NK cell function.

a Degranulation and interferon-γ (IFN-γ) production of naïve and memory Ly49H⁺ WT and Themis2^–/– Ly49H⁺ natural killer (NK) cells after co-culture with m157-expressing RMA cells. Flow cytometry plots are representative of 3 experiments (n = 3 wells ( + RMA) and 5 wells (+RMA-m157)). Data are pooled from 3 experiments (n = 8 wells (Effector alone; Naïve WT, Naïve Themis2^–/–, Memory WT), 7 wells (Effector alone; Memory Themis2^–/–), 9 wells ( + RMA; Naïve WT, Naïve Themis2^–/–), 7 wells ( + RMA; Memory WT), 8 wells ( + RMA; Memory Themis2^–/-–), 10 wells ( + RMA-m157; Naïve WT, Naïve Themis2^–/–), and 11 wells ( + RMA-m157; Memory WT, Memory Themis2^–/–)). b Secondary expansion of memory WT and Themis2^–/– NK cells in recipient Tyrobp^–/– mice after mouse cytomegalovirus (MCMV) infection. Secondary expansion of memory WT and Themis2^–/– NK cells on day 7 pi is represented as the fold expansion of the number of memory NK cells in infected Tyrobp^–/– mice relative to that in uninfected Tyrobp^–/– mice. Data are pooled from 2 experiments (n = 6 mice in each group). c Host protection by naïve and memory NK cells. Naïve and memory Themis2^+/+ and Themis2^–/– Ly49H⁺ NK cells were transferred separately into recipient Tyrobp^–/– mice and then infected with MCMV. The copy number of MCMV IE1 gene in the spleen and liver was quantified on day 3 pi. Data are pooled from 2 experiments (n = 4 mice (Naive), 8 mice (Memory), and 1 mouse (No NK)). Statistical analysis was performed using one-way ANOVA. Data are presented as mean values ±SD (a–c). Source data are provided as a Source Data file.