High levels of tau protein were found in the detergent soluble fractions: 1.235 × 105 ± 0.556 × 105 pg/ml brain lysate in the 20-month-old female 3xTg-AD control mice (n = 14), with small reductions in the mouse groups that had received Aβ42 immunotherapy (1.201 × 105 ± 0.44 × 105 pg/mg in the peptide-immunized mice [p = 0.9754, n = 9], and 0.928 × 105 ± 0.324 × 105 pg/mg [p = 0.1285] in DNA-immunized mice [n = 7]). Here, MAPT is linked to Alzheimer disease.