Fig. 5: Epithelial integrity in uninfected and P. berghei-infected SGs.

a Diffusion of proteins into and out of SGs. Left: hemolymph proteins enriched within iSGs, right: saliva proteins found in infected hemolymph at 19 days post-infection (dpi). Arrows: direction of diffusion. b Lipophorin (LP) and tubulin (loading control) western blot on uSGs (U) and iSGs (Pb) at 21 dpi (n = 2 independent experiments). c Apyrase and Lp (loading control) western blot on uSGs (U) and iSGs (Pb) at 9 and 21 dpi. No SG invasion is detected at 9 days; whereas SGs are heavily infected by 21 days. Lipophorin is used as a loading control (n = 2 independent experiments). d Dextran diffusion assay in SGs 21 dpi. Dextran (green), mCherry parasites (red), and WGA (magenta) (n = 2 independent experiments). e Dextran diffusion quantification (n = 2). Group differences were tested with a chi-square test (χ² = 51.14; p < 1 × 10⁻⁵). f Representative images of saliva texture within the secretory cavities. Black arrow: electro-lucent areas and granular texture in iSGs, white arrow: homogeneous saliva texture in uninfected SGs, black dashed area: sporozoites (n = 3 independent experiments). g Fluorescence images showing interactions between hemocytes and SGs. DNA (blue), dextran (green), mCherry (red), and WGA (magenta). uSGs: 1 and 1’, iSGs: 2 to 3”. WGA was omitted in 1 and 2. Merged colors: 1’ and 2”. Closer view of iSGs: 3, 3’. Lateral view of iSGs: 3” (n = 2 independent experiments). h Quantification of SG-bound hemocytes: uSGs (U) (N = 44) and iSGs (Pb) (N = 38). The graph represents an aggregate of two independent experiments. Horizontal red line: median, ****P ≤ 0.0001 (two-sided Mann-Whitney test). i Intercellular‑junction morphology. Adjacent acinar cells (AC) in uSGs display continuous, electron‑dense junctional complexes (white arrowheads) with opposing membranes fully apposed, and no visible intercellular cleft. In iSGs, junctions appear discontinuous; the plasma membranes disengage, forming a conspicuous intercellular space (white arrowheads). Yellow arrowheads indicate sporozoites (n = 2 independent experiments). Source data are provided as a Source Data file.