Fig. 1. Isolation of highly purified primary human IECs. IECs were isolated as described, and purity was assessed by flow cytometry. Nearly 100% of cells showed positive staining for the epithelial cell marker EP-4 (A), whereas less than 2% of cells stained positive for CD-3 (B) or CD-33 (C). Isotype control staining was negative (D). Data are representative of five experiments.