Isolation and phenotype analysis of tissue-resident lymphocytes from mouse colon.

The intestinal epithelium consists of a single layer of cells that includes enterocytes, enteroendocrine and goblet cells. This monolayer is in close contact with the underlying lamina propria and spatially segregates the gut microbiota and other environmental stimuli from the mucosal immune system. Under certain circumstances, however, gut bacterial components and/or metabolites can perturb tissue homeostasis resulting in abnormal immune responses and tissue damage. In this context, some bacterial toxins, besides stimulating an inflammatory response, may contribute to the activation of pathways related to carcinogenesis. Since immunosurveillance represents a critical barrier to an emerging tumor, characterizing tissue resident immune cells can prove a relevant tool for translational research. The protocol described herein describes the required steps for the isolation and flow cytometry phenotype analysis of tissue resident immune cells from mouse colon following repeated exposure to a pathogenic E. coli toxin as model stimulus.