Interactions between NK cells, microglia, and Th17 cells influence the expression of EAE. (A) CD4⁺ T cells were sorted from the lymph nodes and spleen of 2D2 transgenic mice and cultured under conditions for EAE induction (see Materials and methods). Subsequently, 2 × 10⁵ cells were injected i.v. into MOG/CFA/PT-primed RAG1^−/−γc^−/− mice. Simultaneously, the same numbers of microglia from Cx3cr1^+/− or Cx3cr1^−/− mice and NK cells from the IL-2 complex–treated mice were injected into the brain as previously described (Cardona et al., 2006b). In some experiments, Qa1 was overexpressed on microglia with a lentiviral vector (see Materials and methods). Development of EAE in the recipient mice was monitored and compared. P < 0.05 after day 10 after cell transfer (Mann-Whitney U test) for comparisons between groups receiving 2D2 cells versus 2D2 cells with microglia (except for the group receiving Qa1 overexpressing microglia) and for groups receiving 2D2 cells with microglia versus 2D2 cells with microglia + NK cells. P > 0.05 (Mann-Whitney U test) at all time points for comparisons among the groups of mice receiving 2D2 cells versus 2D2 cells with microglia and NK cells and for groups receiving untransfected versus Qa1-transfected microglia. n = 8–12/group. Error bars represent the means ± SEM. (B) Anti-NK1.1 mAb fails to dramatically alter the course of EAE in IL-17–deficient mice. WT and IL-17^−/− mice were immunized with MOG/CFA. Groups of the immunized mice also received anti-NK1.1 mAb or control IgG (see Materials and methods) upon immunization. Development of EAE was monitored and compared. P < 0.05 after day 10 (Mann-Whiteney U test) for comparisons between IL17^+/+ mice that received anti-NK1.1 mAb and all of the other groups. P > 0.05 (Mann-Whitney U test) at all time points for comparisons among the remaining groups except for IL-17^+/+ mice that received anti-NK1.1 mAb. n = 12–15/group. Error bars represent the means ± SEM. Data from A and B are pooled from three similar experiments.