Prions and immune system

Transmissible spongiform encephalopathies (TSE) are fatal neurodegenerative diseases of humans and animals. The underlying infectious agent, the prion, accumulates not only in the central nervous system (CNS) but also in secondary lymphoid organs. I will revisit the role of the immune system in peripheral prion pathogenesis, while focusing on the mechanisms by which extraneural and extralymphatic prion infectivity develops. Interestingly, the same pro-inflammatory cytokines and homeostatic chemokines that are involved in lymphoid neogenesis and compartmentalization of immune cells appear to represent the crucial molecular switches responsible for the establishment of extraneural prion reservoirs.