Dose–response study of NK cells administered to the CNS of CX3CR1−/− EAE mice. (A) Preliminary test of 1 × 104, 2.5 × 104, 5 × 104, and 1 × 105 WT NK cells implanted into the cerebral ventricles of CX3CR1−/− mice, with vehicle-implanted CX3CR1−/− and CX3CR1+/+ mice as controls. The quantification test showed that a total of 5 × 104 WT NK cells restored the disease manifestations of CX3CR1−/− mice to comparable to those of CX3CR1+/+ mice. n = 6 per group. (B) Final dose–response study of 1 × 104, 2.5 × 104, 5 × 104, and 1 × 105 ChAT+ NK cells. n = 6 per group. Mean ± SEM.