Fig. 4. Polyclonal antibodies to PfTRAP inhibit parasite invasion and traversal in vitro.

Mice were immunized three times with PfTRAP or PfCSP ectodomains. a Immune sera were used to verify binding to Pf sporozoites via immunofluorescence. Shown are fixed, permeabilized sporozoites labeled with a 1:800 dilution of polyclonal anti-PfTRAP mouse serum (followed by anti-mouse IgG secondary; green channel), fluorescently labeled anti-PfCSP monoclonal antibody 2A10 (red channel, right image) and DAPI nuclear stain (blue channel, right image); 10-µm scale bars are shown. Immune serum was then assessed for function in vitro for inhibition of invasion (b) and traversal (c). In b and c, each data point is the average “% of pre-immune” invasion or traversal from technical triplicates in independent experiments; two separate immunization experiment sets are represented as “PfTRAP cohort 1” and “PfTRAP cohort 2”. Each bar indicates the group mean, with error bars representing standard error of the mean and percent change from 100% (shown as dashed line) shown above. Asterisks indicate a significant difference from 100% as determined by a two-tailed one-sample t-test where * is p ≤ 0.05; ** is p ≤ 0.01; and **** is p ≤ 0.0001.