Experimental Design. (A) Mice were divided into 3 experimental groups (n = 10 each group): PBS-treated Non-Transgenic mice (NTg); PBS-treated 3xTg-AD mice, and scFv-h3D6 treated 3xTg-AD mice. (B) Once a month, starting at 5 months of age, mice were intraperitoneally administered with the treatment (100 μg of scFv h3D6) or with the vehicle (PBS). (C) Behavioral and cognitive testing was longitudinally assessed at 5, 7, and 9 months of age 24 h after the corresponding administration. The sorting of the tests was performed based on the degree of stress in each test, with the most stressful one at the end. The corner test (CT) and open-field test (OFT) were carried out on day 1 and the Morris water maze (MWM) on days 3–14 (3–8 MWM, 9–14 reversal MWM).