Antibody blockade of ICAM-1 and VCAM-1 ameliorates inflammation in the SAMP-1/Yit adoptive transfer model of Crohn's disease in mice

Background & Aims: Integrins (alpha (4) and beta (2)) and their endothelial ligands vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhes ion molecule-1 (ICAM-1) play key roles in leukocyte recruitment to areas of inflammation. ICAM-1 and VCAM-1 are expressed in inflamed intestinal tissu es. This study investigates a possible causative role of adhesion molecules ICAM-1, VCAM-1, and alpha (4) integrins in mediating the inflammatory resp onse in a murine model of Crohn's disease (CD). Methods: CD4(+) mesenteric lymph node cells from SAMP-1/Yit donor mice were adoptively transferred int o major histocompatibility complex-matched severe combined immunodeficiency disease mice. Six weeks later, these mice were left untreated or treated f or 3 days with monoclonal antibodies (mAbs) to ICAM-1, VCAM-1, or both, and alpha (4), or both ICAM-1 and alpha (4), dexamethasone, or nonblocking iso type control antibodies. On day 4 after treatment, tissues were investigate d for expression of ICAM-1, VCAM-1, and for severity of inflammation using a semiquantitative inflammatory score. Dexamethasone treatment resolved all measures of intestinal inflammation. Results: Blocking either ICAM-1, VCAM -1, or alpha (4) integrins had no significant beneficial effect. However, b locking ICAM-1 and alpha (4), or blocking ICAM-1 and VCAM-1, showed a 70% r esolution of the active inflammation, but not chronic inflammation. Conclus ions: These findings suggest that blocking ICAM-1 and VCAM-1 may have thera peutic benefit for the acute inflammatory component of Crohn's disease.