Nicola Pussini
Susan Smith
Judy L. Williamson
Bradford Powell
Jorge E. Osorio
Tonie E. Rocke
2010
<p><span>Baits containing recombinant raccoon poxvirus (RCN) expressing plague antigens (fraction 1 [F1] and a truncated form of the V protein-V307) were offered for voluntary consumption several times over the course of several months to a group of 16 black-tailed prairie dogs (</span><i>Cynomys ludovicianus</i><span>). For comparison, another group of prairie dogs (</span><i>n</i><span> = 12) was injected subcutaneously (SC) (prime and boost) with 40 μg of F1-V fusion protein absorbed to alum, a vaccine-adjuvant combination demonstrated to elicit immunity to plague in mice and other mammals. Control animals received baits containing RCN without the inserted antigen (</span><i>n</i><span> = 8) or injected diluent (</span><i>n</i><span> = 7), and as there was no difference in their survival rates by Kaplan–Meier analysis, all of them were combined into one group in the final analysis. Mean antibody titers to </span><i>Yersinia pestis</i><span> F1 and V antigen increased (</span><i>p</i><span> < 0.05) in the vaccinated groups compared to controls, but titers were significantly higher (</span><i>p</i><span> < 0.0001) in those receiving injections of F1-V fusion protein than in those orally vaccinated with RCN-based vaccine. Interestingly, upon challenge with approximately 70,000 cfu of virulent </span><i>Y. pestis</i><span>, oral vaccination resulted in survival rates that were significantly higher (</span><i>p</i><span> = 0.025) than the group vaccinated by injection with F1-V fusion protein and substantially higher (</span><i>p</i><span> < 0.0001) than the control group. These results demonstrate that oral vaccination of prairie dogs using RCN-based plague vaccines provides significant protection against challenge at dosages that simulate simultaneous delivery of the plague bacterium by numerous flea bites.</span></p>
application/pdf
10.1089/vbz.2009.0050
en
Mary Ann Liebert, Inc.
Consumption of baits containing raccoon pox-based plague vaccines protects black-tailed prairie dogs (Cynomys ludovicianus)
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