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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Publications at this Location » Publication #282654
Title: Immunization with synthetic peptide vaccine fails to protect mule deer (Odocoileus hemionus) from chronic wasting disease

Author
item PILON, J - Animal And Plant Health Inspection Service (APHIS)
item RHYAN, J - Animal And Plant Health Inspection Service (APHIS)
item WOLFE, L - Colorado Division Of Wildlife
item DAVIS, TRACY - Colorado Division Of Wildlife
item MCCOLLUM, M - Animal And Plant Health Inspection Service (APHIS)
item O'Rourke, Katherine
item SPRAKER, T - Colorado State University
item VERCAUTEREN, K - Animal And Plant Health Inspection Service (APHIS)
item MILLER, M - Colorado Division Of Wildlife
item GIDLEWSKI, T - Animal And Plant Health Inspection Service (APHIS)
item NICHOLS, T - Animal And Plant Health Inspection Service (APHIS)
item MILLER, L - Animal And Plant Health Inspection Service (APHIS)
item NOL, P - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2013
Publication Date: 7/1/2013
Citation: Pilon, J.L., Rhyan, J.C., Wolfe, L.L., Davis, T., Mccollum, M.P., O'Rourke, K., Spraker, T.R., Vercauteren, K.C., Miller, M.W., Gidlewski, T., Nichols, T.A., Miller, L.A., Nol, P. 2013. Immunization with synthetic peptide vaccine fails to protect mule deer (Odocoileus hemionus) from chronic wasting disease. Journal of Wildlife Diseases. 49(3):694-698.

Interpretive Summary: Chronic wasting disease (CWD) is a fatal brain disease of deer and elk. The disease is transmitted readily in captive herds and as many as 80% of the deer in an infected herd may have evidence of disease. CWD is apparently caused by exposure to misfolded forms of a normal protein found in deer; in diseased animals, the normal prion protein is folded into a novel shape and apparently becomes the infectious agent. The spread of CWD in the US and Canada has been devasting to the captive deer industry; tens of thousands of deer and elk have been destroyed and movement of animals among herds sharply limited. None of the conventional control measures has demonstrated promise once an infected animal enters a herd. A vaccine to protect deer against the disease would therefore relieve the deer industry of the tremendous expense of CWD. In this study, small portions of the normal cellular prion protein were prepared synthetically and combined with a substance that enhances the immune response. Mule deer were vaccinated by injection of the mixture into the muscle. The vaccinated deer produced antibodies to the protein fragments used in the vaccine. Vaccinated and unvaccinated deer were then exposed to CWD by housing in a pen contaminated with the disease causing agent. All deer, regardless of vaccination status, developed CWD, demonstrating that the presence of antibody to the protein fragments was not sufficient to prevent disease. Although this vaccine failed to protect deer, additional trials with vaccines prepared using other fragments of the prion protein or administered in food might be more successful.

Technical Abstract: Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy of deer and elk. The disorder is characterized by accumulation of an abnormally folded isoform of the normal cellular prion protein. Disease prevalence in farmed herds of white tailed deer can exceed 80%. Attempts to control CWD in farmed deer include depopulation of infected herds, movement restrictions, and mandatory diagnostic testing of animals removed for any reason. These efforts have not been successful and CWD continues to be found in herds in several regions of the US and Canada. Development of a protective vaccine for CWD would be economically beneficial for the captive cervid industry. In this study, two synthetic peptides representing residues 166-179 and 143-160 of the normal cellular prion protein were prepared in adjuvant and were administered intramuscularly in mule deer (Odocoileus hemionus), a natural host of CWD. Inoculated deer and control deer, inoculated with adjuvant only, were challenged by natural exposure to an environment contaminated with infectious prion proteins. All vaccinates developed a humoral immune response to the peptides used in the vaccine. However, all vaccinated and control deer developed CWD at approximately the same interval after challenge. Failure of this vaccine to protect deer may have been due to selection of the specific peptide sequences used or the route of inoculation. Identification of a humoral response to inoculation with sequences derived from the normal cellular protein is encouraging, however, and additional trials with other peptides by other routes may be useful in vaccine development.