However, the number of CD8+ T cells migrating in the brain was similar in wild-type and 3xTg-AD mice at 6 months, but was significantly lower in 3xTg-AD mice than wild-type animals at 9 months (Fig. 1g; Supplementary Fig. 1), suggesting that the role of CD8+ T cells may diminish over time in 3xTg-AD mice. This evidence concerns the gene CD8A and Alzheimer disease.