Role of Palatine Tonsils as a Prion Entry Site in Classical and Atypical Experimental Sheep Scrapie |
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Authors: | Maria G. Cancedda Giovanni Di Guardo Roberto Chiocchetti Francesca Demontis Giuseppe Marruchella Caterina Sorteni Caterina Maestrale Alfio Lai Ciriaco Ligios |
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Affiliation: | aIstituto Zooprofilattico Sperimentale of Sardinia, Sassari, Italy;bUniversità degli Studi, Facoltà di Medicina Veterinaria, Teramo, Italy;cUniversità degli Studi, Dipartimento di Scienze Mediche Veterinarie, Bologna, Italy |
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Abstract: | Atypical and classical scrapie-infected sheep brain tissue was monolaterally injected into the tonsils of lambs to investigate their role as a prion entry point. We first detected classical PrPSc within the inoculated tonsil and in the ipsilateral retropharyngeal lymph node at 3 months postinoculation (p.i.). At 7 months p.i., PrPSc colonized other lymphoid tissues bilaterally, including ileal Peyer''s patches. The earliest PrPSc deposition within the brain was ipsilaterally observed at 9 months p.i. in the substantia reticularis of the medulla oblongata. At 12 months p.i., PrPSc deposition was present bilaterally in the nucleus parasympathicus nervi vagi, as well as in the intermediolateral cell column of the thoracolumbar spinal cord. No PrPSc was detected in the lambs inoculated with atypical scrapie. These findings suggest that neuroinvasion may naturally occur from the tonsil after a widespread prion replication within the lymphoid tissues during classical scrapie only, thus mimicking the pathogenesis after oral ingestion. |
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