Effect of anti-LFA-1 monoclonal antibody on rat small bowel allograft survival and circulating leukocyte populations

Anti-LFA-l monoclonal antibodies (mAb) prolong graft survival in several an imal models. This study assessed the effect of an anti-LFA-l mAb (WT.1) on small bowel allograft rejection, circulating leukocyte subsets and in vivo target cell antigen blockade. Heterotopic small bowel transplantation was p erformed between PVG donor and DA recipient rats. Transplanted animals rece ived 1 mg/kg per day WT.1 on days - 1, 0 (day of transplantation) and 1. Th ree doses of WT.1 were also administered to a group of untransplanted anima ls to monitor circulating leukocyte populations and in vivo binding. WT.1 p rolonged recipient survival from 7 to 14 days. Peripheral leukocyte counts increased more than twofold, primarily due to marked increases in both CD4( +) and CD8(+) lymphocytes. Approximately 85% of WT.1 binding sites on lymph ocytes and monocytes were blocked/modulated after the course of therapy. WT .1 has marked effects on circulating leukocytes and target cell binding cap acities and can affect the survival of rat small bowel transplant recipient s. (C) 2000 Elsevier Science B.V. All rights reserved.