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Waffarn EE, Khosravi-Maharlooei M, Vecchione A, Shao S, Vishwasrao P, HÖlzl MA, Frangaj K, Sykes M, Li HW. Mixed xenogeneic porcine chimerism tolerizes human anti-pig natural antibody-producing cells in a humanized mouse model. Xenotransplantation 2021; 28:e12691. [PMID: 33904221 DOI: 10.1111/xen.12691] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/11/2021] [Accepted: 04/09/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND A major obstacle to the success of organ transplantation from pigs to humans, necessitated by the shortage of human organs, is robust humoral immune rejection by pig-reactive human antibodies. Mixed xenogeneic hematopoietic chimerism induces xenoreactive B cell tolerance in rodents, but whether mixed pig/human chimerism could induce tolerance of human B cells to pig xenoantigens is unknown. METHODS We investigated this question using a humanized mouse model in which durable mixed (pig-human) xenogeneic chimerism can be established. RESULTS Human natural anti-pig cytotoxic antibodies, predominantly IgM, are detectable in non-chimeric humanized mouse serum, and pig-reactive antibodies were reduced in mixed chimeric versus non-chimeric humanized mice. This difference required persistent mixed chimerism and was not due to the adsorption of antibodies on pig cells in vivo. Furthermore, human B cells from spleens of mixed chimeric mice produced lower levels of anti-pig antibodies when stimulated in vitro compared with those from non-chimeric mice. CONCLUSIONS Our findings demonstrate that mixed chimerism reduces human natural antibodies to pig xenoantigens, providing the first in vivo evidence of human B cell tolerance induction by mixed xenogeneic chimerism and supporting further evaluation of this approach for inducing human B cell tolerance to xenografts.
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Affiliation(s)
- Elizabeth E Waffarn
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Mohsen Khosravi-Maharlooei
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Andrea Vecchione
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Steven Shao
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Paresh Vishwasrao
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Department of Hematology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Markus A HÖlzl
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Kristjana Frangaj
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Megan Sykes
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Hao Wei Li
- Department of Medicine, Columbia Center for Translational Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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