Fig 1. Immunogenicity of RhPD1-based vaccines in mice.

(A) Schematic of DNA vaccination in mice. C57BL/6 mice were immunized with the empty pVAX vector, pGag, pRhPD1-Gag or pRhPD1-p27 via intramuscular injection with 3 consecutive electroporation in 3-week intervals. Immunological analysis was performed at 2 weeks or 6 months after the last immunization. (B)—(E) Acute humoral and cellular immunity induced by sPD1-based vaccines 2 weeks post-last immunization. (B) Anti-Gag antibody titers in sera. (C) Gag-specific cellular immune responses in spleens evaluated by IFN-γ ELISpot assays. (D) Representative FACS plots showing the presence of H-2D^b/AL11-specific CD8⁺ T cells in the spleens of vaccinated mice by tetramer staining analysis. (E) Frequencies of H-2D^b/AL11-specific CD8⁺ T cells in vaccinated mice. (F) The efficacy of the sPD1-based vaccines against recombinant vaccinia virus challenge. Two weeks after last immunization, mice were challenged with recombinant vaccinia virus MVTT-SIV_gpe via intranasal route. Viral loads in the lungs were determined two days after challenge. (G)—(I) Memory humoral and cellular immune responses elicited by the sPD1-based vaccines at 6 months post last immunization. (G) Anti-Gag IgG titers in sera. (H) Gag-specific IFN-γ ELISpot responses and (I) the frequencies of H-2D^b/AL11-specific CD8⁺ T cells in spleens.