Detection of PrP in extraneural tissues

Area of Science:

• Neuroscience
• Immunology
• Pathology

Background:

• Transmissible spongiform encephalopathies (TSEs), or prion diseases, are fatal neurodegenerative disorders.
• These diseases are characterized by the accumulation of abnormal prion protein (PrPSc) from normal cellular prion protein (PrPc).
• The exact nature of the TSE infectious agent remains debated, with possibilities including a nucleic acid or PrPSc alone.

Purpose of the Study:

• To review immunocytochemical methods for detecting PrP in murine extraneural tissues.
• To discuss the role of the peripheral lymphoid system in TSE pathogenesis.
• To highlight findings on cellular targeting of TSE infection.

Main Methods:

• Immunocytochemistry was used to detect PrP.
• Studies focused on PrP accumulation in the central nervous system (CNS) and extraneural tissues, particularly lymphoid tissues.
• Mice lacking the PrP gene (PrP-/-) were used to assess PrP's role in pathogenesis.

Main Results:

• PrP protein is found in the CNS and extraneural tissues like spleen and lymph nodes in both uninfected and scrapie-infected mice.
• In the peripheral lymphoid system, PrP is associated with follicular dendritic cells.
• Follicular dendritic cells are crucial for the replication of infectivity for certain TSE strains.

Conclusions:

• Prion protein (PrP) is indispensable for TSE pathogenesis.
• Immunocytochemistry is a key tool for understanding PrP's cellular distribution in TSEs.
• The peripheral lymphoid system, especially follicular dendritic cells, plays a significant role in TSE infection and propagation.