Alz50 is an IgM classmonoclonal antibody that stains the fibrillar pathology (dystrophicneurites, neurofibrillary tangles, and neuropil threads) commonlyobserved in postmortem histological analysis of the AD brain.38 The Tau conformational change, targeted by theMC1 antibody, is one of the earliest detectable events in the brainof AD patients. This evidence concerns the gene MAPT and Alzheimer disease.