Reduction of Aβ plaque depositions by anti-apoE immunotherapy. 4-mo-old male APPswe/PS1ΔE9 mice were intraperitoneally injected with PBS vehicle or anti-apoE antibody (HJ6.3) weekly for 14 wk. (A and B) Brain sections from 7-mo-old mice were immunostained for Aβ plaques with anti-Aβ antibody (82E1-biotin). Bar, 250 µm. The extent of Aβ plaque load was quantified in cortex (C) and hippocampus (D). The number of plaques per unit area was quantified in cortex (E) and hippocampus (F). n = 7 for PBS group; n = 18 for HJ6.3 group. To determine the statistical significance (***, P < 0.001), a two-tailed Student’s t test was used. Variance in all graphs represents SEM.