Figure 2. The CS-specific CD8+ T-cell priming effect of PPV-PYCS is markedly enhanced by boosting with replication competent VACV vector expressing CS.

Different groups of BALB/c mice (5 per group) were immunized s.c with 10 or 50 µg of PPV-PYCS [PPV(10 µg) and PPV(50 µg) respectively] or with VACV vectors in prime/boost protocols. Fourteen days after the boost CS-specific IFN-γ secreting cells for the plasmodial epitope SYVPSAEQI in splenocytes were measured by ELISPOT as described under Materials and Methods. The results are expressed as the mean of triplicate assays using cultured pooled splenocytes. Statistical values were determined by one-way ANOVA; P values, *P<0.05, **P<0.01, ***P<0.001.