Fig 4. Morphological transformation of T. vaginalis on exposure to hVECs.

A. TH17 trophozoites (a) were co-incubated with hVECs for 15 (b. and c.), 30 (d, e, f), or 60 min (g and h) for SEM. White triangles point to the flagellum (Fg), axostyle (Ax), or membrane protrusions (Pt). The representative morphology was observed from at least ~50 trophozoites at stages as specified in the infection course. B. The trophozoites treated with DMSO or CytD were cultured in T25 flasks for 1 hr and the morphology was monitored by phase-contrast microscopy. The black and white arrowheads respectively indicate the amoeboid and flagellate forms of T. vaginalis. The percentage of flagellate against amoeboid trophozoites was measured in 600 trophozoites within 6 microscopic fields as shown in the bar graph. C. TH17 trophozoites treated with DMSO or CytD were fractionated into F-actin and G-actin-containing fractions for western blotting. The ratio of the α-actin signal in G-actin versus F-actin was quantified as shown in the bar graph. α-Tubulin (α-Tub) and TvCyP2 were detected as the purity markers of F-actin and G-actin fractions, respectively. D. The trophozoites pretreated with DMSO or CytD were co-cultured with hVECs (moi 1:3) for 1 hr in cytoadherence binding assay. The number of trophozoites bound per 1000 hVECs was measured as shown in the bar graph (mean ± SD). All experiments were repeated three times. Significant differences were statistically analyzed by the Student’s t-tests, with P<0.01(**) and P<0.05(*).