Since T cells frequently penetrate the AD brain and induce excessive inflammatory response compared to the healthy brain [23], we examined the number of infiltrating CD4+ T cells in the brains of WT, WT/Spib−/−, 5xFAD, and 5xFAD/Spib−/− mice using flow cytometry (Fig. 4A). Here, SPIB is linked to Alzheimer disease.