Elicitation of strong immune responses by a DNA vaccine expressing a secreted form of hepatitis C virus envelope protein E2 in murine and porcine animal models

Figure 5 Antibody responses of piglets to HCV E2 vaccines. Piglets were immunized by saline, E2 DNA vaccine three times, or E2 DNA vaccine twice followed by subcutaneous vaccination with E2 protein formulated with CpG ODN 2007 and 10% Emulsigen at three-week intervals. ELISA assays were performed to determine E2-specific IgG, IgG1, and IgG2 levels (A), as well as the ratios of IgG2 to IgG1 (B) (P < 0.05 vs plasmid; P < 0.0001 vs saline).