PSEN1 and B cell deficiency: Analysis of spatial learning using the MWM revealed that compared with age- and sex-matched APP/PS1 or WT littermates, B-cell deficiency significantly improved learning deficiency in APP/PS1 mice as evident by latency to reach the escape platform (F(2,33 = 8.288, p = 0.0012; WT vs APP/PS1 p = 0.0006, APP/PS1 vs APP/PS1-BKO p = 0.003, n = 12, Fig. 2D); and in the number of platform region crossings in a probe test conducted 24 h following learning (Kruscal–Wallis ANOVA p = 0.0004; WT vs APP/PS1 p = 0.0002; APP/PS1 vs APP/PS1-BKO p = 0.028, Fig. 2E).