Prolonged survival of rat islet and skin xenografts in mice treated with donor splenocytes and anti-CD154 monoclonal antibody

Abstract

Treatment of C57BL/6 mice with one transfusion of BALB/c spleen cells and a brief course of anti-CD154(anti-CD40 ligand) antibody permits BALB/c islet grafts to survive indefinitely and BALB/c skin grafts to survive for ~50 days without further intervention. We now report adaptation of this protocol to the transplantation of islet and skin xenografts. We observed prolonged survival of rat islet xenografts in mice treated with donor-specific spleen cell transfusion and anti-CD154 monoclonal antibody (mAb). Challenge islet xenografts placed on these animals indicated that graft acceptance was species-specific but not strain specific. Spleen cells from recipients bearing intact grafts led to rejection of rat islet xenografts in scid mice, suggesting that graft acceptance was not due to complete clonal deletion of xenoreactive cells. We also observed prolonged survival of rat skin xenografts in mice treated with donor-specific transfusion and anti-CD154 mAb. Prolonged survival of skin xenografts was also species specific. We conclude that treatment with appropriately timed donor-specific transfusion and anti-CD154 mAb induces durable survival of both islet and skin xenografts in mice. Because this procedure is targeted directly at CD154, a co-activation molecule expressed predominantly by activated CD4 + T-cells, the results suggest that CD4 + cells have a major role in the cellular immune response to xenografts. Diabetes

Natural killer T cell facilitated engraftment of rat skin but not islet xenografts in mice

“…The results of graft survival in Ja18 null mice in this study are consistent with our previously reported differences in islet vs. skin xenograft survival [2,3]. We report here that NKT cells are not required for islet xenograft survival, but are required to promote durable skin xenograft survival.…”

“…In order to understand the requirements for this induction, we studied cellular elements that may contribute to xenograft survival. We found that the induction of xenograft survival is similarly effective in both thymectomized and in euthymic mice [2]. Additional studies demonstrated that the elimination of CD4 + cells but not CD8 + cells enhances xenograft survival [3].…”

“…The DST consisted of a single transfusion of 10 · 10 6 viable LEW spleen cells in a volume of 0.20 to 0.4 ml given via the tail vein 7 days before grafting. The anti-CD154 mAb treatment consisted of four intraperitoneal injections at dose of 0.5 mg (or 0.25 mg) given twice weekly beginning on the day of spleen cell injection [2].…”

Anti‐mouse CD154 antibody treatment facilitates generation of mixed xenogeneic rat hematopoietic chimerism, prevents wasting disease and prolongs xenograft survival in mice

“…Co-stimulation blockade induces prolonged but not permanent skin allograft and xenograft survival [24,[30][31][32]. In contrast, islet allograft and xenografts can survive permanently in mice treated with co-stimulation blockade [25,30,31].…”

Costimulatory blockade prevents early rejection, promotes lymphocyte apoptosis, and inhibits the upregulation of intragraft interleukin-6 in an orthotopic liver transplant model in the rat

“…Dosing regimens were based on results from other reports in the literature. 9,[13][14][15] Each transplant recipient was assigned a coded number, and those caring for the animals, measuring outcomes, and analyzing samples were blinded to the treatment group. The Animal Ethics Committee stipulated that surviving animals be killed on or before day 8 if they showed signs of impending liver failure (Ͼ20% loss in weight, reduced activity, or bilirubin Ͼ 200 IU/L).…”