Figure 7.

Sera from immunized mice recognized native PfRH5 in P. falciparum NF54 schizont extracts, and exerted an inhibitory effect in vitro. In (A), endpoint titers of anti-samPfRH5 and TEV mRNA PfRH5 sera were measured (titers of Log10, no statistical difference between the groups). Individual sera of 5 liposome-packaged RNA-immunized mice were tested in endpoint dilutions. For coating, ELISA plate schizont extracts were used instead of recombinant PfRH5 antigens. (B) Sera from samPfRH5- and TEV PfRH5 RNA-immunized mice were used to recognize extracts from P. falciparum NF54. Lane 1 is pooled sera from samPfRH5-immunized mice, lane 2 from TEV PfRH5-immunized mice, and Ctr, controls from pre-immune sera. In (C), the percentage of growth inhibition of parasite proliferation (measured by flow cytometry) is shown for two dilutions of purified IgGs from four mice immunized with encapsulated samPfRH5 or TEV PfRH5. The shown values were calculated by comparing parasitemias in parallel cultures supplemented with 300 µg/mL non-related IgG (=0% growth inhibition, for samPfRH5 is shown to average 26% ± 1.5 for 180 µg/mL and 43.1% ± 2.4 for 300 µg/mL in 24 h; average 214.5% ± 4.5 for 180 µg/mL and 24% ± 9.5 for 300 µg/mL in 48 h; in the case of TEV PfRH5, average of 29.4% ± 2 for 180 µg/mL and 49% ± 3.5 for 300 µg/mL). Analyses assuming equal variance and non-parametric values showed no difference between 24 h antisera from both RNA immunizations, and a large difference after 48 h of cultivation, Kruskal–Wallis test, *** = 0.0001) The values are shown for 24 h and 48 h of inhibition. See Supplementary Figure S2 for original Western blot X-ray film.