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Mahr B, Pilat N, Granofszky N, Muckenhuber M, Unger LW, Weijler AM, Wiletel M, Steiner R, Dorner L, Regele H, Wekerle T. Distinct roles for major and minor antigen barriers in chimerism-based tolerance under irradiation-free conditions. Am J Transplant 2021; 21:968-977. [PMID: 32633070 PMCID: PMC7984377 DOI: 10.1111/ajt.16177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/10/2020] [Accepted: 06/19/2020] [Indexed: 01/25/2023]
Abstract
Eliminating cytoreductive conditioning from chimerism-based tolerance protocols would facilitate clinical translation. Here we investigated the impact of major histocompatibility complex (MHC) and minor histocompatibility antigen (MiHA) barriers on mechanisms of tolerance and rejection in this setting. Transient depletion of natural killer (NK) cells at the time of bone marrow (BM) transplantation (BMT) (20 × 106 BALB/c BM cells → C57BL/6 recipients under costimulation blockade [CB] and rapamycin) prevented BM rejection. Despite persistent levels of mixed chimerism, BMT recipients gradually rejected skin grafts from the same donor strain. Extending NK cell depletion did not improve skin graft survival. However, F1 (C57BL/6×BALB/c) donors, which do not elicit NK cell-mediated rejection, induced durable chimerism and tolerance. In contrast, if F1 donors with BALB/c background only were used (BALB/c×BALB.B), no tolerance was observed. In the absence of MiHA disparities (B10.D2 donors, MHC-mismatch only), temporal NK cell depletion established stable chimerism and tolerance. Conversely, MHC identical BM (BALB.B donors, MiHA mismatch only) readily engrafted without NK cell depletion but no skin graft tolerance ensued. Therefore, we conclude that under CB and rapamycin, MHC disparities provoke NK cell-mediated BM rejection in nonirradiated recipients whereas MiHA disparities do not prevent BM engraftment but impede skin graft tolerance in established mixed chimeras.
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Affiliation(s)
- Benedikt Mahr
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Nina Pilat
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Nicolas Granofszky
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Moritz Muckenhuber
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Lukas W. Unger
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Anna M. Weijler
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Mario Wiletel
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Romy Steiner
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Lisa Dorner
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
| | - Heinz Regele
- Clinical Institute of PathologyMedical University of ViennaViennaAustria
| | - Thomas Wekerle
- Section of Transplantation ImmunologyDepartment of SurgeryMedical University of ViennaViennaAustria
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Pilat N, Granofszky N, Wekerle T. Combining Adoptive Treg Transfer with Bone Marrow Transplantation for Transplantation Tolerance. CURRENT TRANSPLANTATION REPORTS 2017; 4:253-261. [PMID: 29201599 PMCID: PMC5691126 DOI: 10.1007/s40472-017-0164-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW The mixed chimerism approach is an exceptionally potent strategy for the induction of donor-specific tolerance in organ transplantation and so far the only one that was demonstrated to work in the clinical setting. Regulatory T cells (Tregs) have been shown to improve chimerism induction in experimental animal models. This review summarizes the development of innovative BMT protocols using therapeutic Treg transfer for tolerance induction. RECENT FINDINGS Treg cell therapy promotes BM engraftment in reduced conditioning protocols in both, mice and non-human primates. In mice, transfer of polyclonal recipient Tregs was sufficient to substitute cytotoxic recipient conditioning. Treg therapy prevented chronic rejection of skin and heart allografts related to tissue-specific antigen disparities, in part by promoting intragraft Treg accumulation. SUMMARY Adoptive Treg transfer is remarkably effective in facilitating BM engraftment in reduced-intensity protocols in mice and non-human primates. Furthermore, it promotes regulatory mechanisms that prevent chronic rejection.
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Affiliation(s)
- Nina Pilat
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Nicolas Granofszky
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Thomas Wekerle
- Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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Mahr B, Wekerle T. Murine models of transplantation tolerance through mixed chimerism: advances and roadblocks. Clin Exp Immunol 2017; 189:181-189. [PMID: 28395110 PMCID: PMC5508343 DOI: 10.1111/cei.12976] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2017] [Indexed: 02/06/2023] Open
Abstract
Organ transplantation is the treatment of choice for patients with end-stage organ failure, but chronic immunosuppression is taking its toll in terms of morbidity and poor efficacy in preventing late graft loss. Therefore, a drug-free state would be desirable where the recipient permanently accepts a donor organ while remaining otherwise fully immunologically competent. Mouse studies unveiled mixed chimerism as an effective approach to induce such donor-specific tolerance deliberately and laid the foundation for a series of clinical pilot trials. Nevertheless, its widespread clinical implementation is currently prevented by cytotoxic conditioning and limited efficacy. Therefore, the use of mouse studies remains an indispensable tool for the development of novel concepts with potential for translation and for the delineation of underlying tolerance mechanisms. Recent innovations developed in mice include the use of pro-apoptotic drugs or regulatory T cell (Treg ) transfer for promoting bone marrow engraftment in the absence of myelosuppression and new insight gained in the role of innate immunity and the interplay between deletion and regulation in maintaining tolerance in chimeras. Here, we review these and other recent advances in murine studies inducing transplantation tolerance through mixed chimerism and discuss both the advances and roadblocks of this approach.
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Affiliation(s)
- B. Mahr
- Section of Transplantation Immunology, Department of SurgeryMedical University of ViennaViennaAustria
| | - T. Wekerle
- Section of Transplantation Immunology, Department of SurgeryMedical University of ViennaViennaAustria
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Granofszky N, Farkas AM, Muckenhuber M, Mahr B, Unger L, Maschke S, Pilat N, Holly R, Wiletel M, Regele H, Wekerle T. Anti-Interleukin-6 Promotes Allogeneic Bone Marrow Engraftment and Prolonged Graft Survival in an Irradiation-Free Murine Transplant Model. Front Immunol 2017; 8:821. [PMID: 28769930 PMCID: PMC5515831 DOI: 10.3389/fimmu.2017.00821] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/29/2017] [Indexed: 01/06/2023] Open
Abstract
Transfer of recipient regulatory T cells (Tregs) induces mixed chimerism and tolerance in an irradiation-free bone marrow (BM) transplantation (BMT) model involving short-course co-stimulation blockade and mTOR inhibition. Boosting endogenous Tregs pharmacologically in vivo would be an attractive alternative avoiding the current limitations of performing adoptive cell therapy in the routine clinical setting. Interleukin-6 (IL-6) potently inhibits Treg differentiation and its blockade was shown to increase Treg numbers in vivo. Therefore, we investigated whether IL-6 blockade can replace adoptive Treg transfer in irradiation-free allogeneic BMT. Treatment with anti-IL-6 instead of Treg transfer led to multi-lineage chimerism (persisting for ~12 weeks) in recipients of fully mismatched BM and significantly prolonged donor skin (MST 58 days) and heart (MST > 100 days) graft survival. Endogenous Foxp3+ Tregs expanded in anti-IL-6-treated BMT recipients, while dendritic cell (DC) activation and memory CD8+ T cell development were inhibited. Adding anti-IL-17 to anti-IL-6 treatment increased Treg frequencies, but did not further prolong donor skin graft survival significantly. These results demonstrate that IL-6 blockade promotes BM engraftment and donor graft survival in non-irradiated recipients and might provide an alternative to Treg cell therapy in the clinical setting.
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Affiliation(s)
- Nicolas Granofszky
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Andreas M Farkas
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Moritz Muckenhuber
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Benedikt Mahr
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Lukas Unger
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Svenja Maschke
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Nina Pilat
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Raimund Holly
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Mario Wiletel
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
| | - Heinz Regele
- Clin. Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Thomas Wekerle
- Department of Surgery, Section of Transplant Immunology, Medical University of Vienna, Vienna, Austria
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