June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Regulatory T cells Modulate Th1 Alloimmune Response by Early Suppression of Graft-site Antigen Presenting Cells via TGF-β1
Author Affiliations & Notes
  • Rohan Bir Singh
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Tomas Blanco
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Hayate Nakagawa
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Hamid Alemi
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Thomas Dohlman
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Yihe Chen
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Sunil Chauhan
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Jia Yin
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Reza Dana
    Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States
  • Footnotes
    Commercial Relationships   Rohan Singh, None; Tomas Blanco, None; Hayate Nakagawa, None; Hamid Alemi, None; Thomas Dohlman, None; Yihe Chen, None; Sunil Chauhan, None; Jia Yin, None; Reza Dana, None
  • Footnotes
    Support  NIH R01 EY12963
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 917. doi:
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    • Get Citation

      Rohan Bir Singh, Tomas Blanco, Hayate Nakagawa, Hamid Alemi, Thomas Dohlman, Yihe Chen, Sunil Chauhan, Jia Yin, Reza Dana; Regulatory T cells Modulate Th1 Alloimmune Response by Early Suppression of Graft-site Antigen Presenting Cells via TGF-β1. Invest. Ophthalmol. Vis. Sci. 2021;62(8):917.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Corneal transplants performed in inflamed high-risk(HR) host beds result in markedly higher immune graft rejection compared to low-risk(LR) setting, primarily due to maturation of host antigen-presenting cells(APCs) & their ability to allosensitize host Thelper1(Th1) cells. We examined the immunomodulatory function of regulatory T-cells(Tregs) in suppressing graft-site APC maturation in the early stages post-transplantation.

Methods : HR & LR allogeneic corneal transplantations were performed with C57BL/6 mice as donors & BALB/c as hosts. On days 3&7, post-transplantation CD4+CD25+FoxP3+ Tregs &phenotypic maturation markers on CD11b+MHC-IIhi APCs were assessed by flow cytometry in graft recipient mice. Tregs from graft sites were FACS sorted from HR or LR recipient mice & co-cultured to precondition bone marrow GM-CSF-generated CD11b+APC(1:20) in the presence of LPS(100ng/ml) & IL-2(10ng/ml) for 48 h. APC maturation markers were evaluated by flow cytometry & proinflammatory cytokine production was assessed by ELISA. Also, sorted Tregs were co-cultured with syngeneic bone marrow GM-CSF-generated CD11b+ APC & sonicated allogenic splenocytes(1:20:21) as above in the presence of anti-TGFβ1 blocking Ab. Subsequently, Tregs were removed, CD4+CD25- naïve T cells were added for 5 days, IFNγ production was assessed by ELISA.

Results : Tregs frequencies & their functional phenotype (measured by FoxP3 expression) were significantly higher in LR compared to HR(p<0.01). Frequencies of MHC-IIhi,CD80,CD86,CCR7 in CD11b+APC were found significantly lower in LR compared to HR(p<0.001). Expression of MHC-II, CD80, CD86, CCR7, production of IL-1β,IL-12 was significantly reduced in LPS-stimulated APC co-cultured with LR Tregs compared to HR (p<0.001). Blocking with TGF-β1 antibodies abolished the suppressive effect of LR Tregs. IFN-γ production was significantly lower in the supernatant of CD4+CD25- naïve T cells co-cultured with LPS-stimulated APC-preconditioned with LR Tregs, this effect was abolished when anti-TGFβ1 Ab was added to the preconditioned media.

Conclusions : These results provide a novel insight into the role of Tregs in suppressing APC maturation at graft-site in the early stages after corneal transplantation and, consequently, suppresses Th1 alloimmunity. These results suggest the therapeutic potential of Tregss in improving graft survival in HR corneal transplantation.

This is a 2021 ARVO Annual Meeting abstract.

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