Figure 2.

Anti-PfMSP10 antibodies have GIA activity. (A) GIA activity of 20 mg/ml rabbit anti-ecto-PfMSP10 antibodies. Rabbit anti-His-GST antibodies, and rabbit anti-EBA175 III-V antibodies were included as negative and positive controls, respectively. Bars indicate mean of three independent experiments, each performed in triplicate. Error bar represents the standard error of the mean. Statistically significant (student's t-test; p < 0.01) data relative to rabbit antibodies against His-GST is shown. (B) Schematic representation of ecto-PfMSP10 and 5 recombinant fragments that were synthesized. Numbers represent amino acid positions. The protein has a predicted N-terminal signal peptide (1–28 aa), an EGF like domain (shown in orange), and a C-terminal GPI anchor. Recombinant PfMSP10 truncates/regions were expressed as N-terminal GST-tagged proteins by the wheat germ cell-free system included region (R)1, amino acid D₂₉-N₁₈₈; R2, N₁₁₀-E₂₆₈; R3, I₁₈₉-V₃₄₈; R4, E₂₆₉-R₄₂₈; and R5, N₃₄₉-Q₅₀₇. (C) Purified recombinant GST-tagged PfMSP10 regions separated by 12.5% SDS-PAGE and stained with CBB. Arrowheads indicate molecular masses as predicted from amino acid sequences. (D) Reactivity of rabbit anti-PfMSP10 antibodies to native PfMSP10. Schizont-rich parasite pellet lysate was resolved under reducing conditions and probed with rabbit antibodies specific to each region. The additional bands (open arrowheads) represent processed fragments. (E) GIA activity of 20 mg/ml rabbit anti-PfMSP10 antibodies raised against each region. Rabbit anti-His-GST antibodies, and rabbit anti-EBA175 III-V antibodies were included as negative and positive controls, respectively. Bars indicate mean of two independent experiments, each performed in triplicate. Error bar represents standard error of the mean. Statistically significant (student's t-test; p < 0.01) data relative to rabbit antibodies against His-GST is shown.