T84/RFP cells are derived from the human colonic adenocarcinoma T84 cell line by stably integration of a constitutive RFP stably expression construct. The T84 cells can form monolayers with tight junctions, making them a good model for studying the epithelial barrier and how it regulates absorption and secretion in the colon. The T84 cells are widely used for ion transport dtudies, drug permeability and absorption, cytokine and inflammation studies, as well as cancer research. T84/RFP cells stably express RFP, can be used for in vitro assays and in vivo imaging.