FIG 1 .

Transcytosis of bacteriophages occurs in a preferential apical-to-basal direction across diverse cell layers. (A) Experimental system to investigate phage transcytosis. Phage T4 was applied to either the apical or basolateral (basal) cell chambers and incubated for 2 h at 37°C, and transcytosed phages were sampled and quantified in the contralateral chamber by bacterial plating. (B) Transcytosis of T4 phages across Madin-Darby canine kidney (MDCK) cells in either an apical-to-basal or basal-to-apical direction. (C) Transcytosis of T4 phages across T84 cells (colon epithelial), CaCo2 cells (colon epithelial), A549 cells (lung epithelial), Huh7 cells (hepatocyte epithelial cell-like), and hBMec cells (brain endothelial). Scatter plots show medians; error bars represent 95% confidence intervals; each point represents the average from three technical replicates.