Peripheral blood and colon or small intestinal specimens were obtained

from IBD patients undergoing small intestinal resection or subtotal colectomy. The rectal specimens were obtained from patients undergoing proctectomy prior to the construction of a pelvic pouch. The patients were either in remission or in a chronic phase of the disease, the former undergoing different forms of reconstructive surgery while the latter were undergoing surgery with curative intent due to active disease. The diagnosis for each patient was determined on the basis of past and present clinical parameters and histopathological criteria post-surgery. The control group consisted of healthy Vincristine clinical trial volunteers (peripheral blood) and patients undergoing therapeutic bowel resection for adenocarcinomas (peripheral blood and colonic specimens). For the specimens from the adenocarcinoma patients only tissue from uninvolved colon was used. The data on the participating individuals are shown in Table 1. Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll/Hypaque (Amersham Biosciences AB, Uppsala, Sweden) Saracatinib in vivo density gradient

centrifugation. When indicated, cells were stained with anti-integrin β7 allophycocyanin (APC) (clone FIB504; Miltenyi Biotec GmbH, Bergisch Gladbach, Germany), incubated with anti-APC-conjugated magnetic beads and separated once on the positive selection program on an Auto-MACS (Miltenyi Biotec GmbH). The positively selected lymphocytes were

91 ± 9% integrin β7-positive, whereas the remaining Chloroambucil lymphocyte population contained 36 ± 12% integrin β7+ lymphocytes as judged by fluorescence activated cell sorter (FACS) analysis. The frequency of integrin β7+ lymphocytes in the unseparated cell population was 56 ± 12%. The mucosal layers of the intestinal specimens were separated mechanically from underlying fat and muscle tissue with scissors and cut into small pieces. The mucosal fragments were incubated 4 × 15 min at 37°C on a magnetic stirrer in RPMI-1640 medium containing 10% AB-serum, 1 mM ethylenediamine tetraacetic acid (EDTA) (Sigma-Aldrich Chemie GmbH, Stienheim, Germany) and 1 mM DL-dithiothreitol (Sigma-Aldrich). Supernatants from the three first incubations, containing IEL, were poured over a nylon mesh, washed twice and kept on ice until further analysis. The remaining mucosal pieces were washed twice with Hanks’ balanced salt solution (HBSS) and were then incubated at 37°C on a magnetic stirrer in RPMI-1640 medium containing 5% AB-serum, 0·1 mg/ml DNAse 1 (D-5025; Sigma-Aldrich) and 100 U/ml collagenase (C-7657; Sigma-Aldrich) for 1·5–2 h.