National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2011

12. Detection of disease-associated prion protein in the small intestines of cattle orally infected with a bovine spongiform encephalopathy agent

Japanese

Twenty-eight calves were orally challenged with to 5 g of homogenized brainstems confirmed as bovine spongiform encephalopathy (BSE) agents. About 2-5 animals were sequentially killed for post-mortem analyses 20 months post-inoculation (MPI) at intervals of 6 or 12 months. Samples from BSE-exposed animals were examined using Western blot and immunohistochemical analyses. Immunolabelled, disease-associated prion protein (PrPSc) was detected in a small portion of follicles in the continuous Peyer's patch from the posterior portion of the small intestine involving the entire ileum and the posterior jejunum but not in the discrete Peyer's patches in the remaining jejunum in preclinical animals at 20, 36, and 48 MPI. PrPSc-positive cells corresponded to tingible body macrophages on double immunofluorescence labelling. In addition, PrPSc accumulated in the central nervous system in 7 of 14 animals after 34 MPI, and 5 developed clinical signs and were killed at 34, 46, 58, and 66 MPI. Two preclinical animals killed at 36 and 48 MPI presented the earliest detectable and smallest deposition of immunolabelled PrPSc in the dorsal motor nucleus of the vagus nerve, the spinal trigeminal nucleus of the medulla oblongata at the obex region, or the intermediolateral nucleus of the 13th thoracic segment of the spinal cord. Serial killing revealed that no PrPSc was detectable with Western blot and immunohistochemical analyses in the central nervous system, including the medulla oblongata at the obex level, before 30 MPI. These results are important for understanding the pathogenesis of BSE.
(Prion Disease Research Center)

References:

Okada H. et al (2011) Transbound. Emerg. Dis. 58(4):333-343

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