Fig. 9

IIV modulated the immune milieu and generated new homeostasis in AD brains. a, b Cytokine array analysis of cytokine levels in the serum of WT, AD and AD+IIV mice. The red frames represent the indicated pro- and anti-inflammatory cytokines, the yellow frames represent chemokines and the white frames represent other cytokines (a) (n = 1, mix of 4 mice/group). Trend graph of the relative signal intensity presented in different categories (b) (n = 1, mix of 4 mice/group) as proinflammatory, anti-inflammatory, chemokines and other cytokines. c, d IL-10 levels in serum (c) and the ratio of Th17 to Tregs in the spleen (d) in AD, AD+IIV and IIV+ATRA mice (n ≥ 6, mean ± SEM, One-way ANOVA, *P < 0.05). e Venn diagram showing the overlap among the indicated cytokines in the serum and brain tissue in the WT, AD and AD+IIV groups. f GO functional enrichment analysis of the biological process of the indicated cytokines obtained from the brains of AD mice and AD+IIV mice. Representative enriched pathways mainly concentrated in leukocyte migration and cell chemotaxis. g Representative cytokine trend graph of the relative signal intensity in the brains of AD and AD+IIV mice presented as proinflammatory, anti-inflammatory and chemokines (n = 1, mix of 4 mice/group). h Correlation analysis between the level of serum IL-10 and the volume of Aβ engulfed by microglia was performed, and a negative relationship was found (Pearson’s r = − 0.6569, P < 0.01)