Mice were anesthetized with sodium pentobarbital (150 mg/kg, i.p.), perfused transaortically and the brains were immediately removed and processed as previously described (Schmidt et al. 2005; Wadghiri et al. 2013). The left hemisphere was snap-frozen for measurement of Aβ oligomers/aggregates, Aβ peptide and pathological tau levels, whereas the right hemisphere was immersion-fixed in periodate-lysine paraformaldehyde. Following fixation, brains were placed in 2% DMSO/20% glycerol in phosphate-buffered saline (PBS) and stored at 4°C until sectioned. Serial coronal brain sections (40 μm) were cut and stained for immunohistochemical analysis with: (i) a mixture of anti-Aβ monoclonal antibodies 6E10/4G8 (Covance, Princeton, NJ, USA), (ii) anti-tau monoclonal antibodies PHF1 and CP13 (kindly provided by Dr. Peter Davies from Albert Einstein College of Medicine, Bronx, NY, USA), (iii) polyclonal anti-glial fibrillary acidic protein (GFAP) antibody (Dako, Carpinteria, CA, USA), (iv) monoclonal anti-CD11 b (Serotec, Raleigh, NC, USA), and (v) anti-CD45 antibodies (Serotec). To ensure that in Aβ 12-28P treated mice reductions of amyloid detection could not be attributed to epitope masking, two different anti-Aβ monoclonal antibodies 6E10 (epitope Aβ 1-16) and 4G8 (epitope Aβ 17–24) with distinct epitopes were used for amyloid detection (Kim et al. 1990). Tau burden was determined by immunostaining with CP13 (recognizes phosphorylated serine in position 202) and PHF1 (recognizes phosphorylated serine in position 396 and 404) (Otvos et al. 1994) antibodies as previously reported (Boutajangout et al. 2011; Asuni et al. 2007). To exam brain inflammation levels of treated mice, we assessed the degree of astrocytosis with GFAP immunoreactivity and the degree of microgliosis with immunoreactivity to CD11b and CD45 antibodies as previously published (Scholtzova et al. 2009; Yang et al. 2011). GFAP is the principal intermediate filament of mature astrocytes, extensively used as a marker for identifying astrocytes in the CNS (Wisniewski and Goni 2013; Stougaard et al. 2011). CD11b is a protein subunit that forms integrin alpha-M beta-2 (αMβ2) (Rubenstein et al. 2011), while CD45 is a protein tyrosine phosphatase (Kutner et al. 2000); CD11b and CD45 monoclonal antibodies are commonly used for detection of the microglial activation at the earliest and later stages of plaque development, respectively (Morgan et al. 2005). Details of the immunostaining techniques were described previously (Sadowski et al. 2006; Scholtzova et al. 2009; Yang et al. 2011; Chung et al. 2010). For control positive immunostaining, human AD sections were used; negative immunostaining controls were performed on sequential mouse brain sections with omission of the primary antibody. Briefly, free-floating sections were incubated in 0.3% H2O2 for 15 min to block endogenous peroxidase activity, and then incubated in a mouse-on-mouse (MOM) blocking reagent from the MOM immunodetection kit (Vector Laboratories, Burlingame, CA, USA) to block nonspecific binding, followed by incubation in a MOM diluent containing different primary antibodies at 4°C overnight, then reacted with biotinylated anti-mouse IgG (1 : 2000) or anti-rat IgG (1 : 1000) secondary antibody for 1 h for all monoclonal antibodies staining. GFAP staining was performed with a primary antibody diluent containing 0.3% Triton X-100, 0.1% sodium azide, 0.01% bacitracin, 1% bovine serum albumin and 10% normal goat serum in PBS, and a secondary biotinylated goat anti-rabbit antibody (Vector). Antibody staining was revealed with 3, 3′-diaminobenzidine (DAB; Sigma-Aldrich) and nickel ammonium sulfate (Ni; Mallinckrodt, Paris, KY) for intensification.