While comparison of the structures reveals differences in the mode of binding of the two antibodies, i.e. binding of CBTAU-22.1 is centered around the buried phosphate pS422 while that of Rb86 is strongly driven by hydrophobic interactions, the demonstrated efficacy of a murine IgG1 version of Rb86 (MAb86) in reducing tau pathology in a mouse model of AD [14] provides further support for the potential of targeting the pS422 epitope. This evidence concerns the gene MAPT and Alzheimer disease.