pS199 tau was also reduced after DNA Aβ42 immunotherapy: 20-month-old 3xTg-AD control mice had a mean 5341 ± 1208 pg/mg wet brain weight in the detergent-soluble fractions, and DNA Aβ42 trimer-immunized mice had a reduced level of 3227 ± 730.5 pg/mg wet brain weight (p = 0.0012). Here, MAPT is linked to Alzheimer disease.