IL-23 Receptor Expression on γδ T Cells Correlates with Their Enhancing or Suppressive Effects on Autoreactive T Cells in Experimental Autoimmune Uveitis

Experimental autoimmune uveitis (EAU), a model of human uveitis, is an organ-specific, T cell-mediated autoimmune disease. Autoreactive T cells can penetrate the blood-retinal barrier, which is a physical defense composed of tight junction-linked retinal pigment epithelial (RPE) cells. RPE cells serve as antigen-presenting cells (APCs) in the eye since they express MHC class I and II and Toll-like receptors (TLRs). Although previous studies have shown that supplementation with TLR agonists exacerbates uveitis, little is known about how TLR signaling in the RPE contributes to the development of uveitis. In this study, we isolated the RPE from EAU mice, which were induced by active immunization (aEAU) or adoptive transfer of antigen-specific T cells (tEAU). The expression of TLRs on RPE was determined, and both aEAU and tEAU mice exhibited induced tlr7 expression. The TLR7 agonist R848 was shown to induce aggressive disease progression, along with significantly elevated levels of the uveopathogenic cytokine IL-17. Furthermore, not only IL-17 but also R848 appeared to enhance the inflammatory response and to impair the barrier function of the RPE, indicating that TLR7 signaling is involved in the pathogenesis of EAU by affecting the behaviors of the RPE and consequently allowing the infiltration of autoreactive T cells intraocularly. Finally, local application of shRNA against TLR7 delivered by recombinant AAV effectively inhibited disease severity and reduced IFN-γ and IL-17. Our findings highlight an immunomodulatory role of RPE TLR7 in EAU development and provide a potential therapeutic strategy for autoimmune uveitis.

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The interaction of dendritic cells and γδ T cells promotes the activation of γδ T cells in experimental autoimmune uveitis

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545816500425 ◽

2017 ◽

Vol 10 (02) ◽

pp. 1650042 ◽

Cited By ~ 3

Author(s):

Beibei Wang ◽

Wei Lin ◽

Jike Song ◽

Xiaofeng Xie ◽

Hongsheng Bi

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Γδ T Cells ◽

Lymphocyte Function ◽

Experimental Autoimmune Uveitis ◽

Autoimmune Uveitis ◽

Experimental Autoimmune

Uveitis is a severe inflammatory disease that can cause visual impairment. Recently, activated [Formula: see text] T cells were proved to play a central role in the development of experimental autoimmune uveitis (EAU). However, the mechanism underlying [Formula: see text] T-cell activation in EAU is incompletely known. In this study, we determined the percentage changes in and the phenotypes of [Formula: see text] T cells and dendritic cells (DCs) obtained from the spleens of immunized C57BL/6 (B6) mice, an animal model of EAU. We found that the number of [Formula: see text] T cells and DCs obviously increased during the inflammation phase of EAU (days 16–20 of our experiment), and that during this time, [Formula: see text] T cells expressed high levels of CD69 and the integrin lymphocyte function–associated antigen-1 (LFA-1) and secreted high levels of interleukin (IL)-17A. Moreover, DCs obtained during this phase expressed high levels of CD80, CD83, CD86, and intracellular cell adhesion molecule-1 (ICAM-1). Furthermore, we studied the interaction between DCs and [Formula: see text] T cells by using flow cytometry and confocal microscopy in order to determine whether DCs affected [Formula: see text] T-cell activation in vitro. Co-cultures of the two types of cells showed that DCs induced high levels of CD69, LFA-1, and IL-17A in [Formula: see text] T cells. Imaging studies revealed contact between the DCs and [Formula: see text] T cells. This interaction was mediated by the accumulation of ICAM-1 and LFA-1 at the interface of DCs-[Formula: see text] T cells. Thus, the activation of [Formula: see text] T cells in EAU was promoted by DCs interacting with [Formula: see text] T cells.

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