We hypothesize that C. concisus, an oral bacterium that is associated with both IBD and BE, has the potential to upregulate the expression of PD-L1 in both intestinal and esophageal epithelial cells and examined this hypothesis using HT-29 and FLO-1 cells as intestinal and esophageal cell culture models, respectively. Here, CD274 is linked to inflammatory bowel disease.