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Wang P, Chen L, Mora-Cartin R, McIntosh CM, Sattar H, Chong AS, Alegre ML. Low-affinity CD8 + T cells provide interclonal help to high-affinity CD8 + T cells to augment alloimmunity. Am J Transplant 2024; 24:933-943. [PMID: 38228228 PMCID: PMC11144556 DOI: 10.1016/j.ajt.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/19/2023] [Accepted: 01/09/2024] [Indexed: 01/18/2024]
Abstract
Following solid organ transplantation, small precursor populations of polyclonal CD8+ T cells specific for any graft-expressed antigen preferentially expand their high-affinity clones. This phenomenon, termed "avidity maturation," results in a larger population of CD8+ T cells with increased sensitivity to alloantigen, posing a greater risk for graft rejection. Using a mouse model of minor-mismatched skin transplantation, coupled with the tracking of 2 skin graft-reactive CD8+ T cell receptor-transgenic tracer populations with high and low affinity for the same peptide-major histocompatibility complex, we explored the conventional paradigm that CD8+ T cell avidity maturation occurs through T cell receptor affinity-based competition for cognate antigen. Our data revealed "interclonal CD8-CD8 help," whereby lower/intermediate affinity clones help drive the preferential expansion of their higher affinity counterparts in an interleukin-2/CD25-dependent manner. Consequently, the CD8-helped high-affinity clones exhibit greater expansion and develop augmented effector functions in the presence of their low-affinity counterparts, correlating with more severe graft damage. Finally, interclonal CD8-CD8 help was suppressed by costimulation blockade treatment. Thus, high-affinity CD8+ T cells can leverage help from low-affinity CD8+ T cells of identical specificity to promote graft rejection. Suppressing provision of interclonal CD8-CD8 help may be important to improve transplant outcomes.
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Affiliation(s)
- Peter Wang
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, Illinois, USA; Medical Scientist Training Program, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
| | - Luqiu Chen
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Ricardo Mora-Cartin
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Christine M McIntosh
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Husain Sattar
- Department of Pathology, University of Chicago, Chicago, Illinois, USA
| | - Anita S Chong
- Department of Surgery, Section of Transplantation, University of Chicago, Chicago, Illinois, USA
| | - Maria-Luisa Alegre
- Section of Rheumatology, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
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