RT Journal Article
A1 Lahdou, Imad
A1 Engler, Christoph
A1 Mehrle, Stefan
A1 Daniel, Volker
A1 Sadeghi, Mahmoud
A1 Opelz, Gerhard
A1 Terness, Peter
T1 Role of Human Corneal Endothelial Cells in T-Cell–Mediated Alloimmune Attack In Vitro
JF Investigative Ophthalmology & Visual Science
JO Invest. Ophthalmol. Vis. Sci.
YR 2014
DO 10.1167/iovs.13-11930
VO 55
IS 3
SP 1213
OP 1221
SN 1552-5783
AB    Human corneal endothelial cells (HCEC) are a potential target of immune attack after corneal transplantation. The aim of this in vitro study was to investigate the role of HCEC during the alloimmune response of T-cells by examining cytokine profiles, function of the immunosuppressive enzyme indoleamine 2,3-dioxigenase (IDO), major histocompatibility complex (MHC-I/-II), T-cell proliferation, and the induction of cell death.    Real-time PCR and RP-HPLC were used to determine IDO expression and activity. Multiplex assay was performed for quantification of cytokine levels. T-cell proliferation was assessed by thymidine incorporation, and HCEC cell death was measured by flow cytometry.    Human corneal endothelial cells induce strong proliferation of allogeneic T-cells and an increase of proinflammatory cytokines such as interleukin-1α (IL-1α), IL-1β, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α). Tumor necrosis factor-alpha (and to a lesser extent IFN-γ) induces apoptosis. Moreover, IFN-γ strongly upregulates MHC-II molecules and IDO activity in HCEC as reflected by high kynurenine (Kyn) concentrations. Interestingly, the T-cell response was not affected by increased IDO activity, since blocking of IDO did not affect the proliferation rate. Indoleamine 2,3-dioxigenase–induced Kyn levels did not exceed concentrations of 175 ± 20 μM. Concentrations of ≥400 μM Kyn were required to suppress T-cell proliferation.    Our data show that T-cell attack on HCEC leads to increased concentrations of proinflammatory cytokines. Inflammatory cytokines induce apoptosis and upregulate MHC-II molecules and IDO in HCEC. Although increased IDO activity does not influence the T-cell response, it constitutes an inflammatory marker of the alloimmune response toward HCEC.  
RD 3/3/2021
UL https://doi.org/10.1167/iovs.13-11930