Figure 4.

Inhibition of Invasion by a Monoclonal Antibody Targeting the Interaction of PvDBP with Its Receptor DARC

(A) Mice were infected with 0.87 million P. vivax sporozoites. Immunomodulation was performed as described in Figure 1A. On day 8, mice were randomized into two groups. Four mice were intraperitoneally injected with 100 mg/kg anti-PvDBP. Four mice served as controls, of which two were injected with 100 mg/kg anti-P. yoelii CSP and two mice were injected with 200 μL PBS. Enriched reticulocytes were injected intravenously on days 9 and 10 post infection.

(B) Thin blood smears were performed 5 h after the second reticulocyte injection (d10pi) and 24 h after the second reticulocyte injection (d11pi). Infected red blood cells were enumerated in 50 fields. The control mice showed a mean of 67.5 parasites on day 10pi, whereas no parasites were seen in the group of mice passively transferred with anti-PvDBP. On day 11pi, one parasite was seen in one of the mice treated with anti-PvDBP, whereas the other three mice of this group remained blood smear negative. Each dot represents one mouse. Mean is shown. Statistics: unpaired t test; ∗∗∗p = 0.0001; ∗∗p = 0.0037.

(C) IFAs were performed on thin blood smears from day 10pi, staining for human CD235a. Thousand cells were counted per slide, and the percentage of human red blood cells was calculated. There was no significant difference between the groups. Shown is mean with SD.

See also Figure S2.