MAPT and Alzheimer disease: The fact that PHFs from AD brains contain truncated tau variants at either one or both N- and C- termini [18, 72, 106], together with an assumption that AD tau fragments contain at least part of an intact MTBR, predisposes DC8E8 antibody with its unique binding tetratop located throughout this region as a promising therapeutic candidate targeting pathogenic (seed-competent) tau species.