CX3CR1−Flag− (CTRL-Tregs) and CX3CR1+Flag+ Tregs (1 × 105 cells/mouse) were adoptively transferred into 5-month-old 3xTg-AD mice via tail vein injection, while wild-type (WT) and 3xTg mice received PBS as controls (Figure 6A). Here, CX3CR1 is linked to Alzheimer disease.