Figure 6. Efficacy of AdHu5-MVA PbMSP142 and PbAMA1 immunization against P. berghei ANKA sporozoite infection.
(a) Mice (n = 6-8/group) were immunized i.d. with 1 × 1010 vp AdHu5 and boosted eight weeks later i.d. with 1 × 107 pfu MVA expressing PbMSP142. Two weeks following the final immunization vaccinated mice and naïve non-immunized controls were challenged with 5 × 102 P. berghei ANKA sporozoites. Each mouse was monitored for the development of blood-stage infection. Parasitemia for individual vaccinated (V) and non-immunized control (C) mice and medians are shown at day 7 following challenge of three different inbred mouse strains (BALB/c, C57BL/6 and C3H). (b) Total IgG responses against recombinant GST-PbMSP-119 protein were measured by ELISA in the serum of mice taken pre-challenge at week 2 post-boost immunization. Individual titers and medians are shown. (c) C57BL/6 and (d) CD1 mice (n = 6–8/group) were immunized i.m. with 8 × 109 vp AdHu5 and boosted eight weeks later i.m. with 1 × 107 pfu MVA expressing PbAMA1. Two weeks following the final immunization vaccinated mice and non-malaria antigen vector-immunized controls were challenged with 2000 P. berghei ANKA sporozoites. Median and individual time to 1% parasitemia is shown. One CD1 mouse showed sterile protection and did not develop patent blood-stage infection.