Accumulating evidence, experimentally and clinically, suggests that chemokines playa fundamental role in the alloimmune response to transplanted organs. In particular, we have found that the chemokine receptor, CXCR3, plays a crucial role and that its blockade either genetically via gene knockout or by monoclonal antibody blockade prevents acute and chronic rejection in murine allograft models. We have therefore produced a humanized monoclonal antibody directed at CXCR3 (SH7) for testing in a nonhuman primate preclinical renal transplant model. Our preliminary results show that this antibody binds to rhesus monkey PBMC and that it?s expression is markedly upregulated on infiltrating leukocytes in acute allograft rejection and to a lesser extent in chronic allograft rejection. We therefore propose to test the safety and efficacy of SH7 therapy in prevention of acute and chronic renal allograft rejection in a rhesus monkey renal transplant model. In addition, we propose mechanistic studies of blood, graft biopsies, and finally urine to evaluate immune activation and regulation. This will include flow cytometry measurement of immune cell subtypes and antibodies, extensive immunocytochemistry studies, real-time PCR (TaqMan) studies, and the trans-vivo Dm response. These studies will allow mechanistic evaluation of the in vivo effects of CXCR3 blockade at a cellular and molecular level that will guide development of preclinical protocols and potentially explain in vivo efficacy. Finally, molecular studies will be employed using laser capture microdissection (LCM) plus cDNA array analysis of selected cell types within allografts to generate useful biomarkers for monitoring rejection versus tolerance induction. These studies will be carried out on biopsy and urinary samples obtained from rhesus monkeys following renal transplantation. Taken together, this proposal offers a comprehensive approach to studying the in vivo efficacy and in vitro mechanisms of CXCR3 blockade in a preclinical nonhuman primate renal allograft model. We plan to take advantage of the combined experience of the Hancock and Knechtle labs to address the research questions posed herein.
| Kwun, J; Oh, B C; Gibby, A C et al. (2012) Patterns of de novo allo B cells and antibody formation in chronic cardiac allograft rejection after alemtuzumab treatment. Am J Transplant 12:2641-51 |
| Uppaluri, Ravindra; Sheehan, Kathleen C F; Wang, Liqing et al. (2008) Prolongation of cardiac and islet allograft survival by a blocking hamster anti-mouse CXCR3 monoclonal antibody. Transplantation 86:137-47 |
| Dar, Wasim A; Knechtle, Stuart J (2007) CXCR3-mediated T-cell chemotaxis involves ZAP-70 and is regulated by signalling through the T-cell receptor. Immunology 120:467-85 |
