Maintenance of graft tissue–resident Foxp3+ cells is necessary for lung transplant tolerance in mice
Wenjun Li, … , Andrew E. Gelman, Daniel Kreisel
Wenjun Li, … , Andrew E. Gelman, Daniel Kreisel
Published March 18, 2025
Citation Information: J Clin Invest. 2025;135(10):e178975. https://doi.org/10.1172/JCI178975.
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Research Article Immunology

Maintenance of graft tissue–resident Foxp3+ cells is necessary for lung transplant tolerance in mice

Abstract

Mechanisms that mediate allograft tolerance differ between organs. We have previously shown that Foxp3+ T cell–enriched bronchus-associated lymphoid tissue (BALT) is induced in tolerant murine lung allografts and that these Foxp3+ cells suppress alloimmune responses locally and systemically. Here, we demonstrated that Foxp3+ cells that reside in tolerant lung allografts differed phenotypically and transcriptionally from those in the periphery and were clonally expanded. Using a mouse lung retransplant model, we showed that recipient Foxp3+ cells were continuously recruited to the BALT within tolerant allografts. We identified distinguishing features of graft-resident and newly recruited Foxp3+ cells and showed that graft-infiltrating Foxp3+ cells acquired transcriptional profiles resembling those of graft-resident Foxp3+ cells over time. Allografts underwent combined antibody-mediated rejection and acute cellular rejection when recruitment of recipient Foxp3+ cells was prevented. Finally, we showed that local administration of IL-33 could expand and activate allograft-resident Foxp3+ cells, providing a platform for the design of tolerogenic therapies for lung transplant recipients. Our findings establish graft-resident Foxp3+ cells as critical orchestrators of lung transplant tolerance and highlight the need to develop lung-specific immunosuppression.

Authors

Wenjun Li, Yuriko Terada, Yun Zhu Bai, Yuhei Yokoyama, Hailey M. Shepherd, Junedh M. Amrute, Amit I. Bery, Zhiyi Liu, Jason M. Gauthier, Marina Terekhova, Ankit Bharat, Jon H. Ritter, Varun Puri, Ramsey R. Hachem, Hēth R. Turnquist, Peter T. Sage, Alessandro Alessandrini, Maxim N. Artyomov, Kory J. Lavine, Ruben G. Nava, Alexander S. Krupnick, Andrew E. Gelman, Daniel Kreisel

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Figure 3

Newly recruited Foxp3+ cells infiltrate BALT within tolerant lung allografts and differ transcriptionally from graft-resident Foxp3+ cells.

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Newly recruited Foxp3+ cells infiltrate BALT within tolerant lung allogr...
(A) BALB/c lungs initially transplanted into CSB-treated B6 CD11c-EYFP mice and then at least 30 days later retransplanted into non-immunosuppressed B6 Foxp3-GFP hosts were imaged with intravital 2-photon microscopy 3 days after retransplantation (n = 3). White arrows point to contacts between Foxp3+ (blue) and CD11c+ (green) cells within the BALT of lung allografts. Rhodamine-dextran labels vessels red. (B) BALB/c lungs initially transplanted into CSB-treated B6 Foxp3-GFP mice and then at least 30 days later retransplanted into non-immunosuppressed B6 Foxp3-RFP recipients were imaged with intravital 2-photon microscopy 3 days after retransplantation (n = 3). White arrows point to contacts between graft-resident (green) and graft-infiltrating (red) Foxp3+ cells within lung allografts. (C and D) BALB/c (CD45.2) lungs were transplanted into CSB-treated B6 (CD45.2) recipients and at least 30 days later retransplanted into non-immunosuppressed B6 (CD45.1) mice. Seven and 21 days after retransplantation, graft-resident (CD45.2) (7 days) and extravasated graft-infiltrating (CD45.1) (7 and 21 days) T cells were sorted from the lung allografts (samples were collected from 4 retransplant recipients and pooled) and processed for single-cell RNA sequencing. (C) Uniform manifold approximation and projection (UMAP) embedding plot of regulatory T cell subpopulations. (D) Heatmap of statistically significant (log2 fold change > 0.25, adjusted P value < 0.05) differentially expressed genes between graft-resident CD45.2 (day 7) and extravasated graft-infiltrating CD45.1 (days 7 and 21) regulatory T cells grouped by condition. (E–I) Representative flow cytometry plots and quantification of abundance of effector memory (CD44hiCD62Llo), central memory (CD44hiCD62Lhi), and naive (CD44loCD62Lhi) graft-resident CD45.2+ versus graft-infiltrating CD45.1+CD90.2+CD4+CD8–Foxp3+ T cells on day 7 (n = 4). Results expressed as mean ± SEM. Scale bars: 20 μm. **P < 0.01, ***P < 0.001. RFP, red fluorescent protein; Tcm, T central memory; Tem, T effector memory.