Alloantibodies are induced antibodies that limit the availability and success of heart and lung allotransplantation. In the presently funded period, we have demonstrated that mice presensitized to alloantigens can be rendered tolerant to these antigens using a non-myeloablative regimen for mixed chimerism induction. However, chimerism induction is markedly impeded by the presence of anti-donor alloantibodies. In the proposed renewal of this project, we will address this problem in both the mouse model and a novel humanized mouse model that we have developed, with the goal of developing a clinically relevant mixed chimerism regimen that will overcome both T and B cell sensitization to the donor. We will:
Aim 1 : Identify the cell types producing anti-donor alloantibodies in presensitized mice and develop methods of depleting them. This information will then be applied to the development of a non-myeloablative mixed chimerism regimen that overcomes both pre-sensitized T cell and alloantibody responses, allowing vascularized heart transplantation in presensitized hosts;
Aim 2 : Identify the human cell types with potential to produce alloantibodies in presensitized humanized mice and develop methods of depleting them. We will develop a protocol for mixed allogeneic chimerism induction in humanized mice and extend this approach to the allopresensitized setting. Natural antibodies (Nab) limit the success of both allogeneic and xenogeneic transplantation. Nab recognition of blood group antigens and of autoantigens exposed by ischemia-reperfusion injury can induce hyperacute and acute humoral rejection and promote other forms of rejection. We have demonstrated grant that mixed chimerism leads to tolerance of anti-carbohydrate (aGal) Nab-producing B cells by an anergy mechanism that is later followed by deletion of donor-reactive B cells. This tolerance is dependent on complement receptor expression by non-hematopoietic cells of the recipient. We hypothesize that tolerance of the B-1b B cells producing Nabs requires interactions with splenic follicular dendritic cells (FDCs) that pick up immune complexes via their complement receptors.
Aim 3 : Determine the role of secreted Ig and complement receptors in the tolerization of natural antibody-producing cells. We will address the hypothesis that immune complexes formed by natural antibodies to donor antigens and complement components target the Nab-producing B cells to FDCs in the spleen, providing a critical activation step that renders the cells susceptible to subsequent anergy and ultimate deletion upon repeated encounter with cell surface-bound antigen on donor-derived hematopoietic cells. _^_____

Public Health Relevance

(Seeinstructions): Together, the studies in this project will allow the improved application of the mixed chimerism approach to overcoming antibody-dependent as well as cellular rejection to the large animal models in this Program Project grant. Through the pipeline of small to large animal models, these studies will ultimately lead to the succesful induction of donor-specific T and B cell tolerance in human recipients with pre-existing antibodies to the heart or lung donor.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Program Projects (P01)
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Heart, Lung, and Blood Initial Review Group (HLBP)
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Massachusetts General Hospital
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Zwang, N A; Zhang, R; Germana, S et al. (2016) Selective Sparing of Human Tregs by Pharmacologic Inhibitors of the Phosphatidylinositol 3-Kinase and MEK Pathways. Am J Transplant 16:2624-38
Newton, Ryan; Priyadharshini, Bhavana; Turka, Laurence A (2016) Immunometabolism of regulatory T cells. Nat Immunol 17:618-25
Madariaga, M L L; Spencer, P J; Michel, S G et al. (2016) Effects of Lung Cotransplantation on Cardiac Allograft Tolerance Across a Full Major Histocompatibility Complex Barrier in Miniature Swine. Am J Transplant 16:979-86
Wang, Zhaohui; Pratts, Shannon G; Zhang, Huiping et al. (2016) Treg depletion in non-human primates using a novel diphtheria toxin-based anti-human CCR4 immunotoxin. Mol Oncol 10:553-65
Hotta, Kiyohiko; Aoyama, Akihiro; Oura, Tetsu et al. (2016) Induced regulatory T cells in allograft tolerance via transient mixed chimerism. JCI Insight 1:
Sihag, Smita; Haas, Michael S; Kim, Karen M et al. (2016) Natural IgM Blockade Limits Infarct Expansion and Left Ventricular Dysfunction in a Swine Myocardial Infarct Model. Circ Cardiovasc Interv 9:e002547
Madariaga, M L; Michel, S G; La Muraglia 2nd, G M et al. (2015) Kidney-induced cardiac allograft tolerance in miniature swine is dependent on MHC-matching of donor cardiac and renal parenchyma. Am J Transplant 15:1580-90
Huynh, Alexandria; DuPage, Michel; Priyadharshini, Bhavana et al. (2015) Control of PI(3) kinase in Treg cells maintains homeostasis and lineage stability. Nat Immunol 16:188-96
Priyadharshini, Bhavana; Turka, Laurence A (2015) T-cell energy metabolism as a controller of cell fate in transplantation. Curr Opin Organ Transplant 20:21-8
Aoyama, A; Tonsho, M; Ng, C Y et al. (2015) Long-term lung transplantation in nonhuman primates. Am J Transplant 15:1415-20

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