Disease-associated prion protein in vessel walls

Human prion diseases like Creutzfeldt-Jakob disease are infectious, inherited, or sporadic neurodegenerative disorders, characterized by the accumulation of an abnormal isoform of the host-encoded prion protein. This affects nervous tissue in sporadic Creutzfeldt-Jakob disease and, additionally, in lymphoid tissue in bovine spongiform encephalopathy-linked variant Creutzfeldt-Jakob disease. Experimental studies have established the involvement of cells of the lymphoid and peripheral nervous system in the transport of prions to their target central nervous system tissue. To evaluate the role of vessel wall-associated mobile cells, we obtained formalin-fixed tissue blocks from various brain regions and/or basal arteries from sporadic, variant and iatrogenic Creutzfeldt-Jakob disease, and unselected control cases. We demonstrate disease-associated prion protein deposits in intracranial vessel walls, in sporadic and variant Creutzfeldt-Jakob disease by performing immunohistochemical staining and paraffin-embedded tissue blotting. Using double immunofluorescence, these deposits colocalize with HLA-DR and S-100 immunoreactive cells in the intima, which are components of the vascular-associated dendritic cell network, as well as with HLA-DR and CD-68 immunopositive macrophages of the intima and media. We conclude that mobile cells in vessel walls like dendritic and monocyte/macrophage lineage cells may be involved in spread of disease-associated prion protein and possibly also of infectivity.