Figure 2

Coimmunization reduces amyloid-β deposition in brains of amyloid precursor protein APP ₆₉₅ mice. Brain sections were taken from 14-month-old Alzheimer’s disease (AD) mice (n = 5) after the fifth immunization and stained by immunohistochemistry as indicated in the Methods section. (A) Plaques revealed by immunohistochemistry. The sections were incubated with amyloid-β42 antibody (anti-Aβ42) used as the primary antibody. WT, wild-type littermates used as negative controls; model, amyloid precursor protein 695 (APP₆₉₅) mice not immunized; co-Aβ42, APP₆₉₅ mice immunized with co-Aβ42 vaccine; pro-Aβ42, APP₆₉₅ mice immunized with protein vaccine. (B) Cortical sections were viewed under a microscope with visible light, and quantification and statistical analysis of plaque counts and plaque area were performed using the Image-Pro Plus version 6.0 software program. (C) Brain sections were taken from 14-month-old AD mice (n = 5) after the fifth immunization and stained with thioflavin S. (D) Cortical sections were viewed under the fluorescence microscope at 488-nm emission, and quantification and statistical analysis of plaque counts and plaque area were performed using the Image-Pro Plus version 6.0 software program. (E) The remaining brain tissues were used to isolate the insoluble protein fraction and analyzed by enzyme-linked immunosorbent assay with a specific monoclonal antibody against Aβ. All data are presented as mean ± SD. Statistical analysis was performed using parametric one-way analysis of variance, and t-tests were used to compare two groups. ns, Not significant. *P < 0.05 compared with APP₆₉₅ mice.