Fig. 6: Salivary gland infection is inhibited in transgenic mosquitoes.

a huPAI-1 reduces sporozoite numbers in the salivary glands of transgenic mosquitoes. Control and transgenic mosquitoes were simultaneously fed on the same P. berghei infected mouse and salivary gland sporozoite numbers were determined 21 days post-feeding. Control experiments were done with either WT mosquitoes or the parental lines MdgD1, QUAS1, QUAS2, SgD1 (Supplementary Data 1, Dataset 7). Horizontal red lines represent the median sporozoite number of data pooled from three independent experiments shown in Supplementary Data 1. Control groups were done with either WT mosquitoes or the parental lines SgD1, MdgD1, QUAS1 or QUAS2 (Supplementary Fig. 5 and Supplementary Data 1, Dataset 7). Statistical analysis was done by two-tailed Mann–Whitney U test, ****P < 0.0001. C control, I inhibition, N number of analyzed mosquitoes. The percent inhibition of median and prevalence was calculated as follows: 100 × [(number of sporozoites in the control − number of sporozoites in the experimental)/(number of sporozoites in the control)]. b, c Salivary glands expressing huPAI-1 are poorly invaded by sporozoites. Salivary glands dissected 21 days post infection were stained with anti-TRAP (parasite; green) and anti-CSP (parasite; magenta) antisera, DAPI (DNA, blue), and WGA (chitin/O-GlcNAcylation; red). Representative WT and Sg1 (c) salivary gland 3D projection (MIP) or single slice confocal images are shown. b WT salivary glands show robust invasion, including sporozoite occupancy of secretory cavities and lumens. c Salivary glands of mosquitoes overexpressing huPAI-1 show sparse invasion frequently mistargeted to the PL lobes (c1-PL1) and dead parasites associated with the basement membrane (c1-PL2, arrow). Interestingly, loss of most sporozoite CSP staining is observed upon invasion (c1-PL1, arrows). Rare DL lobes (4/33) that possessed secretory cavities and/or a lumen showed sporozoite invasion of these regions (arrow in c2-DL2). Data presented in panels b-c are representative of at least two independent experiments. Additional examples of infected salivary glands from the Sg1 line are shown in Supplementary Fig. 6.