Figure 6: Immunization with the TatD-like DNase generates protective immunity against rodent malaria.

(a) rPbTatD-HIS and rPcTatD-HIS were purified by affinity chromatography using His GraviTrap. The SDS–PAGE and western blotting assays revealed that the recombinant proteins were >90% pure. (b) BALB/c mice immunized with Freund’s adjuvant alone or without any immunization (Naive) exhibited 3.12-fold higher parasitaemia than the rPbTatD-immunized group on day 11 post infection; the error bars indicate the s.d. (c) Mice in the rPbTatD-immunized group survived 10 days longer than the two control groups. (d,e) BALB/c mice immunized with Freund’s adjuvant alone and naive mice exhibited 4.66-fold higher parasitaemia than the rPcTatD-immunized group on day 8 post challenge; the error bars indicate the s.d. All of the mice that received Freund’s adjuvant alone and the naive group died on day 9 post infection; however, eight of the mice in the rPbTatD-immunized group were completely protected. (f,g) The group that received serum from a previously infected mouse exhibited 3.97-fold higher parasitaemia than the group that received anti-rPbTatD serum on day 10 post infection. Compared with the other groups, the group that received anti-rPbTatD serum survived for 5 days longer; the error bars indicate the s.d. (h,i) The group that received serum from a previously infected mouse exhibited 1.79-fold higher parasitaemia than the group that received rPcTatD-specific serum on day 10 post infection. The mice that received rPcTatD-specific serum showed a 100% survival rate. The error bars indicate the s.d.