title: Recombinant raccoon pox vaccine protects mice against lethal plague.
abstract: Using a raccoon poxvirus (RCN) expression system, we have developed new recombinant vaccines that can protect mice against lethal plague infection. We tested the effects of a translation enhancer (EMCV-IRES) in combination with a secretory (tPA) signal or secretory (tPA) and membrane anchoring (CHV-gG) signals on in vitro antigen expression of F1 antigen in tissue culture and the induction of antibody responses and protection against Yersinia pestis challenge in mice. The RCN vector successfully expressed the F1 protein of Y. pestis in vitro. In addition, the level of expression was increased by the insertion of the EMCV-IRES and combinations of this and the secretory signal or secretory and anchoring signals. These recombinant viruses generated protective immune responses that resulted in survival of 80% of vaccinated mice upon challenge with Y. pestis. Of the RCN-based vaccines we tested, the RCN-IRES-tPA-YpF1 recombinant construct was the most efficacious. Mice vaccinated with this construct withstood challenge with as many as 1.5 million colony forming units of Y. pestis (7.7 x 10(4)LD(50)). Interestingly, vaccination with F1 fused to the anchoring signal (RCN-IRES-tPA-YpF1-gG) elicited significant anti-F1 antibody titers, but failed to protect mice from plague challenge. Our studies demonstrate, in vitro and in vivo, the potential importance of the EMCV-IRES and secretory signals in vaccine design. These molecular tools provide a new approach for improving the efficacy of vaccines. In addition, these novel recombinant vaccines could have human, veterinary, and wildlife applications in the prevention of plague.
authors.affiliation: Heska Corporation, 1613 Prospect Parkway, Ft Collins, CO 80525, USA. jorge_osorio@powderject.com
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Osorio
authors.forename: Tim D
authors.initials: TD
authors.lastname: Powell
authors.forename: Rexann S
authors.initials: RS
authors.lastname: Frank
authors.forename: Kelley
authors.initials: K
authors.lastname: Moss
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Haanes
authors.forename: Susan R
authors.initials: SR
authors.lastname: Smith
authors.forename: Tonie E
authors.initials: TE
authors.lastname: Rocke
authors.forename: Dan T
authors.initials: DT
authors.lastname: Stinchcomb
mesh_terms: D000818:Animals; D000835:Animals, Wild; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D002522:Chlorocebus aethiops; D005260:Female; D005813:Genes, Synthetic; D051379:Mice; D010930:Plague / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D011212:Poxviridae / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology; D014709:Vero Cells; D014765:Viral Vaccines / Q000276:immunology*; D015010:Yersinia pestis / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; C086725:caf1 protein, Yersinia pestis