Fig. 1.

PfAMA1-RON2L complex protects against virulent P. falciparum challenge. a–c Time course of parasitemia after challenge with 10⁴Pf FVO strain infected RBCs for animals in the control, adjuvant only (a) Group 1), AMA1 (b) Group 2) and AMA1-RON2L complex (c) Group 3). The dashed line at the top indicates limit of parasitemia (200,000 parasites per µL) at which time animals were treated with the antimalarial drug, mefloquine. The dotted line at the bottom indicates the absence of thin smear detectable parasites. T, treatment due to high parasitemia; A, treatment due to anemia; +, a single animal found dead possibly due to anemia; SC, self-cured; SP: animals that remained thin-smear negative until day 41 after challenge when the study was terminated. (d) Kaplan–Meier plot of time-to-patency of animals in Groups 2 and 3. Log-rank was performed to compare time-to-patency (parasite positive by thin blood smear) of animals between Group 2 and Group 3 by the Mantel-Cox test (P = 0.0003). (e) The cumulative parasitemia up to day 14, the day on which the first animal in Group 2 was treated, between Groups 2 and Group 3 by the Mann–Whitney test (P = 0.012)