Tolerance to allogeneic grafts can be achieved in a number of rodent models, and long-term graft survival has been reported in a number of non-human primate models, A consistent feature of stable graft acceptance is the control of alloantibody production;conversely, the appearance of increasing alloantibody titers portends graft rejection, Two divergent interpretations have been advanced to explain these observations- first, that the activation of alloreactive B cells and alloantibodies are simply markers of alloreactive T cell activation and that T cells are solely responsible for the loss of the allograft;second, alloreactive B cells and alloantibodies contribute to graft rejection;either directly or indirectly by synergizing with alloreactive T cells or other effector cells, Because of the well-characterized pathogenic properties of B cells and alloantibodies, we favor the second interpretation and hypothesize that the control of alloreactive B cells, in addition to T cells, is central to stable tolerance, Indeed, the unexpected efficacy of B cell-directed immunotherapy in controlling a number of autoimmune diseases and transplant rejection, pathologies initially thought to be predominantly T cellmediated, suggests an important role for B cells in these clinical settings, The fate of alloreactive T cells has been extensively defined in various models of transplantation tolerance, but there is virtually no information regarding the fate of alloreactive B cells, We have addressed this disparity by developing a novel experimental model to visualize the fate of alloreactive B cells, We observed that transplantation tolerance is associated with the deletion of the mature alloreactive B cells, and a sparing/enrichment of the transitional/immature alloreactive B cells, These observations are consistent with recent reports of a correlation between altered B cell subsets and tolerance in non-human primates and enriched B cell markers in bio-marker studies of spontaneously tolerant kidney transplant recipients, Thus the overall goal of our proposed studies is to define the role of B cells in the induction and maintenance of transplantation tolerance, The first specific aim is to define the mechanistic basis for the selective deletion of mature alloreactive B cells, and to test whether this deletion is essential for the development and/or maintenance of allograft tolerance, The second aim is to further characterize the preserved immature/transitional alloreactive B cells and test whether these cells contribute to the development or maintenance of tolerance, We antiCipate that these studies will provide insights into the role of B cells in transplantation tolerance, and contribute to the development of a clinical strategy that induces and maintains long-term graft survival in the absence of pharmacologic immunosuppression,

Public Health Relevance

The induction of transplantation tolerance for achieving long-term allograft survival in the absence of non- specific and continuous immunosuppression is an important clinical goal. In contrast to most investigations that focus on alloreactive T cells, the studies in this proposal are aimed at defining the role of B cells in transplantation tolerance, and will test whether an independent control of alloreactive B cells is necessary for stable long-term allograft tolerance. We anticipate that these studies will contribute to the development of a clinical strategy that can induce and maintain stable allograft tolerance.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI083452-02
Application #
7897789
Study Section
Special Emphasis Panel (ZRG1-IMM-G (02))
Program Officer
Rice, Jeffrey S
Project Start
2009-07-22
Project End
2011-06-30
Budget Start
2010-07-01
Budget End
2011-06-30
Support Year
2
Fiscal Year
2010
Total Cost
$390,000
Indirect Cost
Name
University of Chicago
Department
Surgery
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Cowan, Michelle; Chon, W James; Desai, Amishi et al. (2014) Impact of immunosuppression on recall immune responses to influenza vaccination in stable renal transplant recipients. Transplantation 97:846-53
Chen, J; Yin, H; Xu, J et al. (2013) Reversing endogenous alloreactive B cell GC responses with anti-CD154 or CTLA-4Ig. Am J Transplant 13:2280-92
Chang, Anthony; Moore, Jocelyn M; Cowan, Michelle L et al. (2012) Plasma cell densities and glomerular filtration rates predict renal allograft outcomes following acute rejection. Transpl Int 25:1050-8
Cowan, Michelle L; Sciammas, Roger; Chong, Anita S (2012) Experimental models of B cell tolerance in transplantation. Semin Immunol 24:77-85
Chong, A S; Sciammas, R (2011) Matchmaking the B-cell signature of tolerance to regulatory B cells. Am J Transplant 11:2555-60
Burns, Audrea M; Chong, Anita S (2011) Alloantibodies prevent the induction of transplantation tolerance by enhancing alloreactive T cell priming. J Immunol 186:214-21
Burns, Audrea M; Ma, Lianli; Li, Yijin et al. (2009) Memory alloreactive B cells and alloantibodies prevent anti-CD154-mediated allograft acceptance. J Immunol 182:1314-24