Experimental study of combined treatment with tacrolimus and donor splenocytes via the portal vein in small bowel transplantation

We previously reported that the combined treatment of perioperative administration of donor splenocytes via the recipient's portal vein (DSPV) and a short-course Tacrolimus significantly prolonged the survival of fully allogenic grafts in rat small bowel transplantation (SBTX). In the present study we examined whether this effect depended on the quantity of the administered alloantigens in DSPV. In addition, we examined the expression of the surface antigen on T cells of the splenocytes and the induced toleragenic factor, according to the tolerant recipients which in our previous report had shown the prolongation of allogenic transplant small bowel graft survival by the combined treatment of DSPV (1×108 donor splenocytes) and a short-course Tacrolimus. Donor splenocytes were prepared from Brown-Norway (BN (RT1n)) rat spleens for Lewis (LEW (RT1l)) recipients. The recipients (n=10), treated with a short course of Tacrolimus (0.5mg/kg, 0 to 3 days postoperatively) only showed graft rejection with an average of 6.3±1.0 days postoperatively. However, the combined treatment, consisting of DSPV of 1×108 donor splenocytes and a short course Tacrolimus significantly prolonged graft survival to 12.7±2.1 days (n=12, P