TREM2 hemizygosity does not significantly affect Aβ plaque burden or expression of M1/M2 microglial markers in 7-month old APPPS1-21 mice. (A and B) Representative coronal brain sections from 7-month old female TREM2 WT (A) and TREM2 Het (B) mice. Sections were immunostained with the biotinylated anti-Aβ antibody, HJ3.4. (C) Quantification of the cortical area occupied by Aβ immunostaining. TREM2 WT (5.85 ± 0.69%, n = 9) and TREM2 Het (4.60 ± 0.66%, n = 7) were statistically compared using a Mann Whitney test (p = 0.25). (D) Quantification of microglial mRNA expression in TREM2 WT and TREM2 Het mice. For each mRNA examined TREM2 Het were normalized and compared to TREM2 WT mice using a t-test followed by Benamini-Hochberg p-value correction for multiple comparisons. All data are presented as mean ± SEM (n = 3-7 mice per group), *p < 0.05.