Fig. 2: Parasite development arrest largely depends on TEP1-mediated mature CSPmut oocyst melanization.
From: Malaria oocysts require circumsporozoite protein to evade mosquito immunity
a Representative image of melanized Plasmodium yoelii CSPmut in mosquitoes under a light microscope on day 12 after a blood meal; scale bar 50 μm. b Representative electron micrograph of vacuolized or melanized sporozoites (white arrows) from P. yoelii CSPwt and CSPmut oocysts at day 11; scale bar 1 μm. c Statistical analysis between the percentage of melanized mature P. yoelii CSPwt and CSPmut oocysts in mosquitoes (n = 45) at the indicated time points post blood feeding. d Average number of sporozoites released from P. yoelii CSPwt and CSPmut oocysts in mosquitoes (n = 60) at indicated incubation times in vitro. e mRNA expression level of TEP1 in mosquitoes (n = 15) infected with P. yoelii CSPwt and CSPmut at the indicated time points post blood feeding determined using real-time PCR. f TEP1 activation (100 kD band) in hemocytes from mosquitoes (n = 40) infected with P. yoelii CSPwt and CSPmut parasites detected using western blot; S7 protein was used as an internal control (left). Pooled data was quantified and analyzed (right). g Representative image of TEP1 binding to P. yoelii CSPwt and CSPmut oocysts at day 7 PI stained with anti-CSP repeat and anti-TEP1 (left), and the percentage of oocysts from P. yoelii CSPwt or CSPmut parasite-infected mosquitoes (n = 30) bound with TEP1 was statistically analyzed (right); scale bar 10 μm. Percentage of melanized mature oocysts (h) in P. yoelii CSPmut parasite-infected mosquitoes (n = 60) at day 12 PI, and average number of hemolymph sporozoites (i) in mosquitoes (n = 60) infected with CSPmut parasites at the indicated time points compared following TEP1 knockdown. d–f A two-sided Student’s t-test was used for the statistical analysis. c, g–i A two-sided Mann–Whitney U test was used for the statistical analysis. The data were presented as the means ± SD; ns, no significance; p-values were shown. The data were combined based on three independent experiments (c–i) or two independent experiments (b). Source data are provided as a Source Data file.
