Immunization initiated at 12 months of age in Tg2576 animals decreases total amyloid deposits. A. Representative photomicrographs of sections from brains of 16 m Tg2576 (Control, CFA, Oligo Aβ and fAβ) that had been immunized as described in Materials & Methods from 12 to 16 months of age immunostained with 6E10 (which reacts with the human amyloid peptide). Scale bar: 100 microns. B. Image analysis (% Field area) of Aβ (6E10 antibody) immunoreactivity in hippocampus and cortex of animals untreated or immunized at 12–16 months. Mean of each animal is the average of 2 sections (except untreated control which is 1 section per animal) assessing 4–8 images per section (most to all of the area of the section was analyzed). Bars represent group mean ± SD of n mice per group: Control n = 6, CFA n = 4, Oligo Aβ n = 7, Aβ n = 4, *p < 0.04, **p < 0.03 by ANOVA.