FIG 5.

Immunogenicity of DNA vaccines targeting poly(P)-regulatory genes. (A) Six- to 8-week-old female C57BL/6J mice (n = 3 or 4) were vaccinated with DNA plasmid (pSectag2B) encoding rel_Mtb, sigE, ppx1, or ppk2 or the empty vector, as illustrated in the scheme. Vaccination and electroporation were performed once weekly for 3 weeks. At 1 week after the last vaccination, sera and splenocytes were collected from each group. (B) ELISA detection of antigen-specific IgG responses from the different mouse vaccination groups. (C) Summary of antigen (Ag)-specific CD4⁺ T-cell responses (positive intracellular staining for IFN-γ [IFN-γ⁺] and TNF-α [TNF-α⁺]) following DNA vaccination. Splenocytes from the individual vaccinated groups were stimulated with 10 μg/ml of each recombinant protein for 24 h at 37°C, and then GolgiPlug cocktail (1 μl/ml) was added overnight. The cells were then stained with anti-mouse CD4, followed by positive intracellular staining for IFN-γ and TNF-α. The data were acquired with a FACSCalibur flow cytometer and analyzed with FlowJo software. *, P < 0.05 compared to the empty vector control. IFN-γ⁻ and TNF-α⁻, negative intracellular staining for IFN-γ and TNF-α, respectively.