Antibody HJ9.3 recognising epitope 306–320 in MTBR, similar to DC8E8 binding epitope, was found to be the only antibody tested with the unique ability to inhibit internalization of repeat-domain tau fibrils and AD tau aggregates in primary neurons with proposed potential mechanism of blocking tau/HSPG interaction [27, 48]. Here, MAPT is linked to Alzheimer disease.