When these TBS extracts are mixed with purified receptor-bound Aß from AD brain, there is a single PrPC-interacting Aß immunoreactivity peak with a size matching migration of globular proteins in the 650 kDa range, consistent with the EM appearance and an assembly of about 250 Aß monomers (Fig. 1h). Here, PRNP is linked to Alzheimer disease.