RD3 and Alzheimer disease: To learn the N- and C-terminal truncations of HMW-tau, we analyzed tau in the above 10 AD and 10 control cases (see Table 1) by western blots developed with phosphorylation-independent monoclonal antibodies against different regions of the tau molecule, including 43D (a.a. 6–18), HT7 (a.a. 159–163), RD4 (a.a. 275–291), RD3 (a.a. 267–274 and 306–313), Tau46 (a.a. 404–421) and Tau46.1 (a.a. 428–441; Figure 4A).