Fig. 3

Differential responses of TIGKs challenged by three Fn model strains under normoxic and asymmetric gas coculture conditions. Morphological comparison of TIGK monolayers in a the medium control (CCM only) and after coculture with b Fn 23726, c Fn 25586, and d Fn 10953 under the asymmetric gas coculture system. The MOI of Fn was 1. Red arrows indicate the adherence of bacterial aggregates to the TIGK monolayer. Due to the presence of the collagen fibers, collagen coating can obscure fine details of the cells or structures being observed compared to uncoated surface.⁶² e Representative flow cytometry results for TIGKs after coculture with three different Fn strains, as assessed by the SYTOX green staining. f Quantification of TIGK viability after asymmetric coculture with Fn 23726, Fn 25586, and Fn 10953 based on the above flow cytometry results (0.01 < *P < 0.05, n = 2, N = 3). g Comparison of fluorescence intensities of FITC-dextran in the basolateral chamber at 24 h after adding FITC-dextran to the apical chamber containing TIGK monolayers receiving different treatment conditions. Undifferentiated TIGKs cultured under the normoxic condition served as the negative control due to the lack of an intact monolayer. Differentiated TIGKs with or without Fn 25586 challenge under normoxic or asymmetric culture conditions were compared. The background fluorescence of the culture medium was subtracted. The MOI was 1 (N.S., P > 0.05, *** P < 0.001, n = 2, N = 3)