Immunoblotting of sarkosyl-insoluble tau from AD and familial MSTD brains. The anti-tau antibodies used were the phosphorylation-independent antisera BR134, BR304, and BR189 and the phosphorylation-dependent antibodies PHF1, AT180, AT100, AT8, and 12E8. The arrows point to the sarkosyl-insoluble tau bands of 60, 64, and 68 kDa seen in AD.