Figure 3. Δlimp parasites are severely impaired in their gliding motility, adhesion and liver cell invasion capabilities.
(A) Dextran assay of sporozoite hepatocyte traversal. NISG: cells incubated with non-infected salivary gland material. WT (four independent experiments; n = 12); Δa (five independent experiments; n = 10); Δb (two independent experiments; n = 6). (B) Sporozoite (Spz) hepatocyte adhesion assay. WT (three independent experiments; n = 6); Δa (three independent experiments; n = 8); Δb (two independent experiments; n = 6). (C) Sporozoite hepatocyte invasion assay. WT (four independent experiments; n = 12; 1292 sporozoites analysed); Δa (five independent experiments; n = 12; 806 sporozoites analysed); Δb (two independent experiments; n = 6; 381 sporozoites analysed). (A–C) Bars show means±SEM; p-values for Student´s t-test. (D) Salivary gland sporozoite (SG Spz) gliding motility assay. Bars show means ± SEM; p-value for Kruskal-Wallis test. WT (four independent experiments; n = 7; 820 sporozoites analysed); Δa (four independent experiments; n = 4; 477 sporozoites analysed); Δb (one experiment; n = 3; 299 sporozoites analysed). (E) Representative images of WT and Δa CSP gliding trails. Scale bars = 10 µm. (F) Cellular ultrastructure of Δa sporozoites is unchanged. (1) plasma membrane; (2) inner membrane complex; (3) subpellicular microtubules; (4) rhoptries; (5) micronemes. (G) Few Δa sporozoites are seen within the mosquito’s salivary gland parenchyma, meaning they actively invaded this tissue and are thus not unviable. (F–G) Scale bars = 200 nm.