MAPT and Alzheimer disease: It’s worth underlying that: (i) the ELISA test aimed at assessing the cerebral amount of injected 12A12mAb is based on the plate-immobilized synthetic NH226-44aa which, being the minimal Alzheimer’s disease-relevant (Borreca et al., 2018) active moiety of the parental longer NH226-230 (Amadoro et al., 2004, 2006), was used as catching peptide; (ii) only the free (i.e. unoccupied) antibody can readily bind to its immobilized specific antigen and be measured, whereas the tau-bound antibody is not detectable.