MAPT and tauopathy: Our previous findings indicated that the effective tau antibody, 4E6, primarily bound to soluble pathological tau, whereas the ineffective antibody, 6B2, had a much higher affinity for insoluble tau, which may lead to neutralization of the antibody.12 Furthermore, since 6B2 does not clear insoluble tau in tauopathy mice, high affinity to that particular epitope may render the aggregates more compact and less amenable to degradation.12,13