Figure 4
Immunogenicity of Gag following Biojector plus EP immunizations with escalating doses of DNA. BALB/c mice were immunized once with Biojector followed by EP with mixtures of 10–1000 μg pKCMVp37B or empty vector and 25 μg pVax-Luc diluted in 100 μl saline. A) 4, 8, 11, 18 and 25 days post DNA injections mice were injected ip with the D-luciferin substrate and expression of luciferase was monitored using the Xenogen In Vivo Imaging System (IVIS). Results are shown as mean values (n = 4) and error bars represent standard error of the mean. B) At day 25, spleens were collected and IFN-γ, IL-2 and IFN-γ/IL-2 responses were assessed by FluoroSpot. A Gag p24B peptide pool was used to assess Gag-specific cellular immune responses, and the H2-Kd restricted GFQSMYTFV (luciferase) peptide was used to assess luciferase-specific responses. Bars represent mean values for the Gag p24B peptide pool. C) Correlation between in vivo expression and frequency of Gag p24B peptide pool-specific IFN-γ, IL-2 and IFN-γ/IL-2 secreting splenocytes at day 25. D) Antibody titers to Gag p17/p24B were assessed by ELISA on serum collected 25 days post immunization. Bars represent mean values. *Significant difference (p < 0.05).