Transmissible mink encephalopathy: studies on the peripheral lymphocyte

Area of Science:

• Veterinary Virology
• Prion Disease Research
• Immunology

Background:

• Transmissible mink encephalopathy (TME) is a fatal prion disease affecting mink.
• The cellular tropism and transmission routes of the TME agent remain incompletely understood.
• Investigating the role of circulating lymphocytes in TME pathogenesis is crucial.

Purpose of the Study:

• To determine the presence of TME virus particles in circulating lymphocytes.
• To assess the infectivity of circulating lymphocytes from TME-affected mink.
• To investigate the potential role of lymphocytes in TME transmission.

Main Methods:

• Electron microscopy of phytohemagglutinin-stimulated lymphocyte cultures.
• Infectivity assays using lymphocytes from TME-affected mink.
• Comparison with infectivity in lymphoid organs.

Main Results:

• No virus-like particles were detected in circulating lymphocyte cultures via electron microscopy.
• Circulating lymphocytes from TME-affected mink were noninfectious.
• The TME agent was infectious in intact lymphoid organs of affected mink.
• A late-stage lymphopenia was observed, likely a secondary stress response.

Conclusions:

• Circulating lymphocytes are not a significant reservoir or transmission route for the TME agent.
• The TME agent is present and infectious within lymphoid organs.
• Lymphopenia in late-stage TME is likely a consequence of terminal illness rather than a direct disease mechanism.