Regulatory T (Treg) cell-based immunotherapies have been studied as potential cell-based modalities for promoting transplant survival. However, the efficacy of local delivery of Treg cells in corneal transplantation has not been fully elucidated. Herein, we investigated the kinetics of migration of subconjunctivally injected Treg cells and their role in promoting corneal allograft survival.
GFP+CD4+CD25+Foxp3+ Treg cells were isolated from draining lymph nodes (DLNs) of GFP transgenic mice and were subconjunctivally injected to corneal allograft recipients. Next, Treg cells, 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 major histocompatibility complex-II+CD11b+ antigen-presenting cells, IFNγ+CD4+ Th1 cells, and CD45+ cells in the DLNs and cornea were evaluated at week 2 posttransplantation using flow cytometry. Expressions of IFNγ, IL-10 and TGF-β in the grafts were assessed using reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay.
GFP+ Treg cells were detected in the ipsilateral cornea and DLNs of recipients 6 hours after injection. Subconjunctival injection of Treg cells significantly decreased the frequencies of mature antigen-presenting cells in the graft and DLNs, suppressed Th1 frequencies in DLNs, and inhibited CD45+ cell infiltration to the graft. Finally, locally delivered Treg cells 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.
Our study elucidates the kinetics of migration of locally delivered Treg cells and shows their role in suppressing host immune response against the allograft.
1 Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA.
2 Department of Ophthalmology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Received 13 February 2018. Revision received 27 August 2018.
Accepted 29 August 2018.
C.S. and Y.C. contributed equally to this study.
The authors declare no conflicts of interest.
This study was supported by the National Institutes of Health/National Eye Institute grant R01 EY012963 to RD.
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.
Correspondence: Reza Dana, MD, MPH, MSc, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary, Harvard Medical School, 20 Staniford Street, Boston, MA 02114. (Reza_Dana@meei.harvard.edu).