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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Publications at this Location » Publication #202285
Title: Investigation of the effects of experimental autolysis on the detection of abnormal prion protein in lymphoid and central nervous system tissues from elk and sheep using the Western blotting method

Author
item HUANG, H - CANADIAN FOOD INSPECTION
item SOUTYRINE, A - Canadian Food Inspection Agency
item RENDULICH, J - CANADIAN FOOD INSPECTION
item O'Rourke, Katherine
item BALACHANDRAN, A - CANADIAN FOOD INSPECTION

Submitted to: Canadian Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2010
Publication Date: 1/3/2011
Citation: Huang, H., Soutyrine, A., Rendulich, J., Orourke, K.I., Balachandran, A. 2011. Investigation of the effects of experimental autolysis on the detection of abnormal prion protein in lymphoid and central nervous system tissues from elk and sheep using the Western blotting method. Canadian Journal of Veterinary Research. 75(1)69-72.

Interpretive Summary: Tissues unsuitable for standard microscopic examination for evidence of chronic wasting disease of elk or scrapie of sheep are often submitted for testing in Canada. In this investigation, a method for testing these tissues using an enrichment step was evaluated. The study showed that the amount of the disease marker PrP-Sc in lymph nodes and brain from prion-positive elk and sheep decreased gradually but was still detectable after 5 and 15 days incubation at body temperature. This assay is therefore a useful screening and confirmatory test for PrP-Sc in these tissues.

Technical Abstract: Chronic wasting disease CWD is a transmissible spongiform encephalopathy of cervid ruminants, including white tailed deer, mule deer, black tailed deer, moose, and elk. The disease is related to the scrapie of sheep. In both diseases, diagnosis is typically made by detection of the disease associated prion protein PrP-Sc using histology, immunohistochemistry, or enzyme-linked immunosorbent assays. CWD in farmed elk and scrapie in domestic sheep are endemic in some regions of Canada. Surveillance of fallen stock is a component of the control program. However, these samples show varying levels of autolysis and bacterial overgrowth. The resulting loss of morphology complicates diagnosis by histology and immunohistochemistry. In this study, the investigators evaluated a sensitive western blot with enrichment of the marker protein PrP-Sc using phosphotungstate acid precipitation. A simulated autolysis trial using tissues held at 37C for 0, 5, or 15 days was conducted, using a commercial enzyme linked immunosorbent assay as a reference test for quantitative measurements. The investigation demonstrated that although the PrP-Sc signal was reduced by autolysis, the western blot analysis could correctly identify the PrP-Sc positive cases. Validation of the method for elk and sheep will allow the Canadian Food Inspection Agency to use a single western blot diagnostic method for all small and wild ruminant species in the prion surveillance programs.