Contribution of C3d-P28 repeats to enhancement of immune responses against HBV-preS2/S induced by gene immunization

Figure 4 Determination of anti-HBs IgG of sera from mice primed by the different plasmid DNAs and boosted with HBsAg protein. Each group of mice (n = 6) was primed im at week 0 with 100 μg of mock DNA (○), pVAON33-S2/S plasmid (●), pVAON33-S2/S-P28 plasmid (△), pVAON33-S2/S-P28.2 plasmid (□), pVAON33-S2/S-P28.3 plasmid (◇) and pVAON33-S2/S-P28.4 plasmid (■), separately. And then boosted sc at week 12 with HBsAg (1 μg per mouse). Sera collected at the indicated times from each group were diluted 1:10 for determination of specific IgG levels by ELISA.