1A) (P < 0.0001), and greater with the 97 day interval than the 57 day interval (P = 0.0006). The antibody response induced by protein–protein (P–P) vaccination was markedly variable with three mice mounting high responses comparable to those receiving A–P immunization, and three very weakly responding mice ( Fig. 1A and B). There was no significant difference learn more between median antibody responses following protein–protein, adenovirus–MVA and adenovirus–protein regimes after a 57 day dose interval (P = 0.37 by Kruskal–Wallis test), but there was a clear increase in the variance of the

response after two shot protein regimes compared to viral-vector containing regimes. In contrast with the antibody results, greater

percentages of IFNγ+ CD8+ T cells were detected by ICS 14 days after A–M immunization than A–P, and the 57 day dose interval was superior (P < 0.0001 for both comparisons) ( Fig. 1A and B). Clear boosting of CD8+ T cell responses by MVA was evident at both dose intervals. As expected, given the lack of the CD8+ T cell epitope in the MSP119 protein sequence in BALB/c mice [5], CD8+ T cell responses were not detectable following P–P vaccination. Additional experiments in C57BL/6 mice (in which a CD8+ T cell epitope is present in the MSP119 protein [5]) confirmed that, in contrast to the A–M regime, P–P GSK2656157 datasheet vaccination did not induce a CD8+ T cell response detectable by IFNγ splenic ELISPOT or peripheral blood ICS, and that CD8+ T cell responses were unaltered by A–P immunization as compared to adenovirus priming alone ( Fig. 1C and D). CD8+ T cell responses after A–P immunization of either mouse strain thus presumably represent the contracting or effector memory CD8+ T cell response induced only by the adenovirus. We subsequently compared the immunogenicity of three-component sequential adenovirus–MVA–protein (A–M–P) and adenovirus–protein–MVA (A–P–M) regimes to two-component regimes (Fig. 2 and Fig. 3). The kinetics of the responses induced by these regimes were markedly different. We found that addition of

protein to adenovirus–MVA (A–M–P) was able to boost antibody but not CD8+ T cell responses (again as would be predicted due to lack of the T cell epitope in this protein) (Fig. 2A), while addition of MVA to adenovirus–protein (A–P–M) boosted CD8+ T cell responses but not antibody titer (Fig. 2B). Total IgG responses to A–M–P and A–P–M were significantly higher than those to A–M (P < 0.05 by ANOVA with Bonferroni post-test), with no significant differences between the responses to A–M–P, A–P–M and A–P (P > 0.05, Fig. 3A). There were no statistically significant differences in CD8+ T cell responses between A–M–P, A–P–M and A–M regimes (P > 0.05 by ANOVA with Bonferroni post-test, Fig. 3B). In general, any two- or three-component regime including AdCh63 and MVA induced maximal CD8+ T cell responses as measured in the blood.