In previous studies, we demonstrated in mice and prairie dogs that simultaneous administration of two recombinant raccoon poxviruses (rRCN) expressing Yersinia pestis
antigens (F1 and V307-a truncated version of the V
protein) provided superior protection against
plague challenge compared to individual single
antigen constructs. To reduce costs of
vaccine production and facilitate implementation of a sylvatic
plague vaccine (SPV) control program for prairie dogs, a dual
antigen construct is more desirable. Here we report the construction and characterization of a novel RCN-vectored
vaccine that simultaneously expresses both F1 and V307
antigens. This dual
antigen vaccine provided similar levels of protection against
plague in both mice and prairie dogs as compared to simultaneous administration of the two single
antigen constructs and was also shown to protect mice against an F1 negative strain of Y. pestis. The equivalent safety, immunogenicity and efficacy profile of the dual RCN-F1/V307 construct warrants further evaluation in field efficacy studies in sylvatic
plague endemic areas.