This study aimed to develop an effective experimental
vaccine against highly pathogenic H5N1
Avian Influenza (HPAI) virus and to optimize their immunization programs. As reported previously, various
DNA-based or recombinant
vaccinia viral(Tiantan)-based H5N1
vaccine candidates, which containing a single cistronic construct (HAop, or
NAop) or a bicistronic construct (HAop/M2 or
NAop/M1) of H5N1 influenza virus (Anhui strain) were constructed and characterized in our lab. In this study, we further analysed the immunogenicity in mice of these
vaccine candidates by various protocols (single or combined immunization). Our results showed that: comparing with immunization with
DNA-based or rTTV-based H5N1
vaccine only, combined
DNA-based with rTTV-based H5N1
vaccine immunization via prime-boost strategy enhanced immune response significantly against multi-H5N1
antigens detected by hemagglutination inhibition (HI) assay, NA- or M1- or M2-specific antibody detection, and micro-
neutralizing antibody test and IFN-gamma ELISpot assay. Priming with
DNA-based
vaccine induced higher level of humoral response against HA or NA
antigen than priming with rTTV-based
vaccine; In contract, M1 and M2-specific antibody levels were higher among that of priming with rTTV -based
vaccine. These findings provide a basis for further development of novel H5N1
vaccines and for the optimization of the immunization programs of combined multi-
antigens vaccine candidates.