Cytopathic effect and cytokine production of S-G, A549, and NCI-H292 cells after stimulation by Trichomonas tenax. A549 (A, B) and NCI-H292 cells (C, D) were co-incubated with T. tenax for 24 h, the attached cells were then stained with Giemsa buffer and the percentage of stained cells was calculated by ImageJ. S-G (E, F), A549 (G, H) and NCI-H292 (I, J) cells were treated with T. tenax at different MOIs for 24 h, and the concentration of IL-6 and IL-1β were detected by ELISA (n.d: not detection, n.s: not significant, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001, MOI: multiplicity of infection).