Figure 2:

Graft-infiltrating γδ T cells and ILC3s are important sources of IL-22 after lung transplantation. (A) Flow cytometric characterization of IL-22⁺ cells types in tolerant Balb/c → B6 CD45.1 lung grafts reveals γδ T cells (RORγt⁺CD3⁺TCRγδ⁺) and ILC3s (RORγt⁺CD3⁻TCRγδ⁻CD127⁺CD90⁺) as main producers. Other IL-22⁺ cells include CD4⁺ T cells (RORγt⁺CD3⁺TCRγδ⁻CD4⁺CD8⁻), double-negative (DN) T cells (RORγt⁺CD3⁺TCRγδ⁻CD4⁻CD8⁻), CD8⁺ T cells (RORγt⁺CD3⁺TCRγδ⁻CD4⁻CD8⁺) and non-T non-ILCs (RORγt⁺CD3⁻TCRγδ⁻CD127⁻CD90⁻). Plots are gated on live single CD45.1⁺ cells. (B) Quantification of RORγt⁺IL-22⁺ cell subpopulations in tolerant lung grafts based on the gating plots described above. Histological appearance of lung allografts 30 days after transplantation into (C) wildtype (WT), (D) γδ T cell-deficient (TCRδ KO) recipients and (E) AR mice (RORγt-cre Ahr^fl/fl) that received peri-operative co-stimulatory blockade. Quantification of the (F) number of lymphoid follicles and (G) percentage of total area occupied by lymphoid follicles per section 30 days after transplantation into various recipients. n≥4 for all conditions. **p<0.01. IL-22 KO: IL-22-deficient; IL-23 neut: IL-23 neutralization. Scale bars: 100μM.