Fig. 3. M cell distribution is already regular in crypts of rabbit Peyer’s patches. Cryostat serial cross-sections of crypts in normal ileum villi (A) and the dome region (B-D) were permeabilized and double-labeled for M cells with anti-vimentin (A-D, red) and MAb 58 (C,D, green) or for dividing cells with anti-BrdU (B, green). Arrowheads mark the junction between crypts (delineated by discontinuous lines) and domes or villi (dotted lines). In normal ileum (A), vimentin labels interstitial tissue but is absent from the overall epithelium, including crypts. In FAE (B-D), vimentin labeling surrounds M cell nuclei on the dome side of crypts (B,C) and above the crypt neck (D). In crypts, starting from BrdU-positive cells (arrows in B), vimentin-labeled cells are regularly spaced (B-D). Apical surface of vimentin-positive cells are also labeled with MAb 58 (C), as in the dome flanks (D). A few cells are co-labeled with anti-vimentin and MAb 58 on the villus side (arrows), both in the crypts (C) and above (D).
