Light microscopic analysis of Caco2–MIC 216 cocultures. Standard periodic acid–Schiff staining on 5-mm cryosections of 10-day cocultures composed of Caco2 cells and pCEN cells (a and b), EpiS2 cells (c and d), and EpiAS1 cells (e and f). Magnification in a, c, and e: ×100; in b, d, and f: ×200.