Fig. 6

Enhanced immunosuppression impaired IIV-induced cognitive improvements in APP/PS1 mice. a, b Flow cytometric analysis of the proportions of CD4⁺CD25⁺Foxp3⁺ Treg splenocytes in the IIV+ATRA or IIV+Vehicle (DMSO) mice. Representative flow panels and quantitative analysis indicated that ATRA increased the percentages of CD4⁺CD25⁺Foxp3⁺ Tregs, compared with AD+IIV and IIV+Vehicle mice (n > 5, mean ± SEM, one-way ANOVA and LSD post hoc test, *P < 0.05, ***P < 0.001). c–f Escape latency in the MWM (c) in the AD (n = 8), AD+IIV (n = 8), IIV+ATRA (n = 6) and IIV+Vehicle (n = 6) mice (mean ± SEM, two-way repeated-measures ANOVA and LSD post hoc test, *P < 0.05, **P < 0.01, ***P < 0.001). The purple asterisk represents the comparison of the AD+IIV and IIV+ATRA mice. The blue asterisk indicates the comparison of the AD mice and AD+IIV mice. The gray asterisk represents the comparison of the IIV+ATRA and IIV+Vehicle mice. Average numbers of platform crossings (e), ratio of time spent and distance traveled (f) and representative trajectories (d) in the target quadrant in each group during the spatial probe phase (one-way ANOVA and LSD post hoc analysis; *P < 0.05, **P < 0.01, ***P < 0.001)