Construction of a bivalent vaccine against anthrax and smallpox using the attenuated vaccinia virus KVAC103

Abstract

Abstract Background Anthrax and smallpox are high-risk infectious diseases, and considered as potential agents for bioterrorism. To develop an effective countermeasure for these diseases, we constructed a bivalent vaccine against both anthrax and smallpox by integrating a gene encoding protective antigen (PA) of Bacillus anthracis to the genome of the attenuated vaccinia virus strain, KVAC103. Results Immunization with this bivalent vaccine induced antibodies against both PA and vaccinia virus in a mouse model. We also observed that the efficacy of this vaccine can be enhanced by combined immunization with immunoadjuvant-expressing KVAC103. Mouse groups co-immunized with PA-expressing KVAC103 and either interleukin-15 (IL-15) or cholera toxin subunit A (CTA1)-expressing KVAC103 showed increased anti-PA IgG titer and survival rate against B. anthracis spore challenge compared to the group immunized with PA-expressing KVAC103 alone. Conclusions We demonstrated that the attenuated smallpox vaccine KVAC103 is an available platform for a multivalent vaccine and co-immunization of immunoadjuvants can improve vaccine performance.

Keywords

• Anthrax
• Smallpox
• Vaccinia virus
• IL-15
• Cholera toxin