FIG 5.

Delivery of PEPCK DNA to intramuscular or intradermal sites induces systemic immune responses. (A) Immunization schedule for tissue-specific DNA vaccination. C57BL/6 mice were immunized twice, 2 weeks apart (n = 4 to 5 per group), either intramuscularly or intradermally. Spleens were harvested 10 days after the final vaccination to analyze antigen-specific T cell responses. (B) The frequency of PEPCK-specific IFN-γ responses (spot-forming units per million splenocytes) induced after vaccination was determined by an IFN-γ ELISpot assay in response to pooled PEPCK peptides. (C) PEPCK-specific CD4⁺ T-cell responses to each consensus plasmid determined by intracellular cytokine staining after peptide stimulation. (D) Polyfunctionality of CD4⁺ T cells in response to PEPCK vaccination in intramuscular and intradermal groups. (E) HEK293T cells transfected with PEPCK plasmids and sera from C57BL/6 mice immunized with the constructs were used to detect antibody binding to PEPCK by an IFA.