THE EFFECT OF ANTI-ICAM-1 MONOCLONAL-ANTIBODY TREATMENT ON THE TRANSPLANTATION OF THE SMALL-BOWEL IN RATS

At present, organ transplantation has been conducted in various areas. But the most crucial problem is to find an efficient way to determine whether allograft rejection could be interfered by a novel approach, namely interference of adhesive interaction between cytotoxic cells and target organs with a monoclonal antibody (mAb) to intercellular adhesion molecule 1 (ICAM-1). We have studied the effect of anti-rat-ICAM-1 mAb on small bowel transplantation. Inbred Fischer and Lewis rats weighing 250 g were utilized. In allotransplantation, Fischer donor small bowel was transplanted to Lewis recipient. Group 1 consisted of untreated controls (n = 15). Group 2 was treated with the anti-ICAM-1 mAb (1 mg/kg/d intraperitoneally) for the first 5 days posttransplantation (n = 15). A dramatic inhibitory effect on allograft rejection was observed in the early stage of posttransplantation. On histological studies of grafted small intestine, group 2 showed normal morphological appearance while group 1 showed graft rejection until postoperative 5 days. However, changing around crypt cells and endothelial cells of microvasculature have appeared at 15 days of posttransplantation. These findings suggest that anti-ICAM-1 antibody is quite useful for delaying the occurrence of graft rejection in the early stage. Electron microscopic examination demonstrated the same results as conventional HE staining. Endothelial cells of the vessels and crypt cells may have an important role as target cells on graft rejection. Therefore, anti-ICAM-1 mAb may have potential as an alternative to conventional treatment for prevention of allograft rejection. © 1993.