Although pretreatment of brain extracts with antibody to Aβ could inhibit seeding, confirming a role for Aβ, experiments using synthetic Aβ peptides (1–40 or 1–42), in either soluble or aggregated forms, failed to transmit infection; neither did oligomeric forms of Aβ prepared from cell cultures overexpressing APP [158]. This evidence concerns the gene APP and infection.