PRNP and Alzheimer disease: Expressed in monomer equivalents, the apparent avidity in a plate-based PrPC-interacting Aß immunoreactivity (PLISA) assay was similar to that for recombinant Aß42 globulomer (12mer), a synthetic Aß42 ADDL preparation in F12 medium (apparent MR of 500,000), as well as unpurified TBS-soluble free Aßo from human AD brain (apparent MR of 1,000,000).