Abstract: A C-T-B PDDV mixture of the three constructed epitope-based peptide-DNA dual vaccines（PDDV）containing the CTL （C）, Th （T） and B-cell （B） epitopes from Sj22.6 tegument （C-PDDV, T-PDDV and B-PDDV） with a 1 ∶ 1 ∶ 1 ratio was prepared. Thirty-six mice were randomly divided into six groups averagely named as 18K group, PBS group, C-PDDV group, T-PDDV group, B-PDDV group, and C-T-B PDDV group. All the mice received three immunizations at 2-week intervals with the same dose of antigen（10 μg DNA+28 μg peptide）. One week after the last immunization, the mice were sacrificed, the spleens were removed and splenocytes were collected. Splenocyte proliferation was assayed by［3H］TdR incorporation after stimulation with soluble worm antigen（SWA）. Levels of IFN-r and IL-4 in the splenocyte culture supernatants were determined by ELISA. The results showed that IFN-r content in T-PDDV group ［（76.0±11.2） pg/ml］ was higher than that of PBS ［（13.0±2.1） pg/ml］ and 18K control groups ［（14.0±3.2） pg/ml］ （P<0.01）. IL-4 level in T-PDDV ［（152.0±21.1） pg/ml］ and C-T-B mixture groups［（86.0±12.2） pg/ml］ was higher than others （P<0.01 and P<0.05）. The splenocytes from T-PDDV group showed a significant increase in proliferation compared with PBS and 18K control groups after stimulation by SWA（P<0.01）. However, there was no significant difference in splenocyte proliferation among C-T-B， PBS and 18K control groups （P>0.05）. These findings indicate that T-PDDV and C-T-B PDDV mixture induces stronger immune response than that of C-PDDV or B-PDDV.

Key words: Schistosoma japonicum, Peptide-DNA dual vaccine, Mouse, Immune response