Local Delivery of Regulatory T Cells Promotes Corneal Allograft Survival

Background Regulatory T cell (Treg)-based immunotherapies have been studied as potential cell-based modalities for promoting transplant survival. However, the efficacy of local delivery of Tregs in corneal transplantation has not been fully elucidated. Herein, we investigated the kinetics of migration of subconjunctivally injected Tregs and their role in promoting corneal allograft survival. Methods GFP+CD4+CD25+Foxp3+ Tregs were isolated from draining lymph nodes (DLNs) of GFP transgenic mice and were subconjunctivally injected to corneal allograft recipients. Next, Tregs, conventional T cells (Tconv) or a combination of both was locally injected to graft recipients, and graft survival was determined by evaluating opacity scores for 10 weeks. Transplanted mice without treatment served as controls. The frequencies of MHC-II+CD11b+ antigen presenting cells (APCs), IFNγ+CD4+ Th1 cells, and CD45+ cells in the DLNs and cornea were evaluated at week 2 posttransplantation using flow cytometry. Expression of IFNγ, IL-10 and TGF-β in the grafts were assessed using RT-PCR and ELISA. Results GFP+ Tregs were detected in the ipsilateral cornea and DLNs of recipients 6 hours after injection. Subconjunctival injection of Tregs significantly decreased the frequencies of mature APCs in the graft and DLNs, suppressed Th1 frequencies in DLNs, and inhibited CD45+ cell infiltration to the graft. Finally, locally delivered Tregs significantly reduced the expression of IFN-γ, enhanced the levels of IL-10 and TGF-β in the graft, and promoted long-term allograft survival. Conclusions Our study elucidates the kinetics of migration of locally delivered Tregs and shows their role in suppressing host immune response against the allograft. * These authors contributed equally to this study. Corresponding Author: Reza Dana, M.D., M.P.H., M.Sc., Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA, Tel: +1-617-912-7401; Fax: +617-912-0117. Email: Reza_Dana@meei.harvard.edu Authorship: Chunyi Shao: Research design, performance of the research, data analysis, writing the paper Yihe Chen: Research design, performance of the research, data analysis, writing the paper Takeshi Nakao: Performance of the research Afsaneh Amouzegar: Data analysis, writing the paper Jia Yin: Performance of the research Maryam Tahvildari: Performance of the research Zala Lužnik: Performance of the research Sunil K. Chauhan: Research design, data analysis, writing the paper Reza Dana: Research design, data analysis, writing the paper Disclosure: The authors have no financial conflicts of interest. Funding: This study was supported by the National Institutes of Health/National Eye Institute Grant R01 EY012963 to RD. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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