Department of ophthalmology, Nanfang Hospital, Southern Medical University , Guangzhou, China.
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University , Guangzhou, China.
Curr Eye Res. 2020 Jul;45(7):774-781. doi: 10.1080/02713683.2019.1705491. Epub 2019 Dec 26.
Endogenous toll-like receptor (TLR) 2 is linked to allograft rejection in corneal transplantation. TLR2 also could modulate dendritic cell (DC) phenotype, resulting in T cell polarization. Thus, we investigated the role of endogenous TLR2 on DC development and T cell polarization during corneal rejection.
Corneas of BALB/c mice were transplanted into the eyes of C57BL/6 wild-type (WT) recipients and (KO) recipients. Graft survival and TLR2 mRNA expression were assessed. At day 14 after transplantation, to study endogenous TLR2 effects on DC development and function, surface expression of MHC classⅡ (MHCⅡ), CD86, CD80 and CD40 in ipsilateral cervical draining lymph nodes (DLNs) is measured by flow cytometry, and DC phenotype in corneas is detected by immunofluorescence. The levels of IL-12, IL-10 and IL-4 in corneas were measured by real time-qPCR (RT-qPCR). The ability of DCs to stimulate T cell polarization was assessed by IFN-γ expressions via RT-qPCR and immunohistochemistry.
TLR2 mRNA expression in corneas was peaked at day 14 post-transplantation in WT group. KO group improved corneal allograft survival compared to the WT group. In addition, the KO group decreased expression of CD86, CD80 and CD40 on DCs compared to the WT group. There was no difference in MHCⅡ expression in two groups. The CD11cMHCⅡCD40 DCs could not be detected in corneas of the KO group. Moreover, the KO group decreased IL-12 (Th1-promoting cytokines) mRNA expression and increasing IL-10 (Treg-promoting cytokines) mRNA expression compared to the WT group. IL-4 (Th2-promoting cytokines) mRNA expression gained no difference between the two groups. The IFN-γ (Th1 cytokines) expression was significantly decreased in the KO group compared to the WT group.
Endogenous TLR2 may contribute to allogeneic corneal rejection via Th1 immunity by activating Th1-promoting DCs and suppressing Treg-promoting DCs.
内源性 toll 样受体 (TLR) 2 与角膜移植中的同种异体移植物排斥反应有关。TLR2 还可以调节树突状细胞 (DC) 表型，导致 T 细胞极化。因此，我们研究了内源性 TLR2 在角膜排斥反应过程中对 DC 发育和 T 细胞极化的作用。
将 BALB/c 小鼠的角膜移植到 C57BL/6 野生型 (WT) 受体和 TLR2 敲除 (KO) 受体的眼睛中。评估移植物存活率和 TLR2 mRNA 表达。在移植后第 14 天，为了研究内源性 TLR2 对 DC 发育和功能的影响，通过流式细胞术测量同侧颈淋巴结 (DLN) 中 MHC Ⅱ类 (MHCⅡ)、CD86、CD80 和 CD40 的表面表达，并通过免疫荧光检测角膜中的 DC 表型。通过实时 qPCR (RT-qPCR) 测量角膜中 IL-12、IL-10 和 IL-4 的水平。通过 RT-qPCR 和免疫组织化学评估 DC 刺激 T 细胞极化的能力。
WT 组角膜中 TLR2 mRNA 表达在移植后第 14 天达到峰值。与 WT 组相比，KO 组改善了角膜同种异体移植物的存活率。此外，KO 组中 CD86、CD80 和 CD40 表达降低。两组之间 MHCⅡ的表达没有差异。在 KO 组的角膜中未检测到 CD11cMHCⅡCD40 DC。此外，与 WT 组相比，KO 组中 IL-12（Th1 促进细胞因子）mRNA 表达降低，IL-10（Treg 促进细胞因子）mRNA 表达增加。两组之间 IL-4（Th2 促进细胞因子）mRNA 表达无差异。与 WT 组相比，KO 组中 IFN-γ（Th1 细胞因子）的表达明显降低。
内源性 TLR2 可能通过激活 Th1 促进的 DC 并抑制 Treg 促进的 DC，通过 Th1 免疫导致同种异体角膜排斥反应。
