Fig. 5: Macrophages/monocytes phagocytose microbiota in mosquito midgut dependent on SR-A.

a Mosquito midgut microbiota was removed by antibiotics and colonized with GFP-tagged-E. anophelis. Mosquitoes were allowed to fed on P. yoelii-infected mice treated with or without CL. Three hours post blood meal, the mosquito midgut was dissected, and FACS were used to detect GFP⁺ macrophages and monocytes (n = 9). Ten mosquitoes were pooled as one biological replicate, and three biological replicates were performed. b Three hours after mosquitoes fed on P. yoelii-infected mice pre-treated with CL or control liposomes, midguts were dissected and homogenized. The homogenate was incubated with antibiotics to eliminate extracellular bacteria, and then intracellular bacteria were released after lysis of macrophages/monocytes by Triton X. The released bacteria were cultured on LB agar plates for 24 h, and CFUs (n = 15) in each group were counted and compared. Ten mosquitoes were pooled as one biological replicate, and five biological replicates were performed. The right panel was the representative image of monocyte/macrophage phagocytosing bacteria in mosquito midgut at 3 h post blood meal, stained with Giemsa solution, scale bar: 5 μm. c The number of live macrophages/monocytes number at different time points in the mosquito midgut (n = 12) was detected by FACS. d The infection intensity and prevalence of mosquitoes fed on infected C3^−/− mice pretreated with or without CL. e, f The infection intensity and prevalence of mosquitoes fed on infected mice pretreated with or without CL, or 10 μg (e) or 50 μg anti-SR-A (f). g The infected mice were pre-treated with 50 μg anti-SR-A at 1 day before, or 1 day post-infection, or treated with CL at 3 days post-infection, then the mice were fed to mosquitoes. 7 days post blood meal, oocysts number in mosquitoes was counted and compared. Three independent experiments were performed for each experiment, and the data were pooled. Data in (a–c) were presented as mean ± SD. In panels of (d–g), the individual dot represents oocysts number per mosquito, with a line indicating the median, and the pi chart under each scatter chart indicates the sample size and prevalence in each group. Source data are provided as a Source Data file. Significance was determined by an unpaired t-test (two-tailed) for (a, b), GLMMs (two-sided) test for (d–h), and Fisher’s exact test (two-sided) was applied for prevalence analysis. Number between each group represent the P-value, P < 0.05 was consider as statistically significant.