Laboratory of Cellular and Molecular Immunology, Gavin Herbert Eye Institute, University of California, Irvine, School of Medicine, Irvine, California, USA.
Laboratory of Cellular and Molecular Immunology, Gavin Herbert Eye Institute, University of California, Irvine, School of Medicine, Irvine, California, USA
J Virol. 2020 Apr 16;94(9). doi: 10.1128/JVI.00140-20.
Invariant natural killer (iNKT) cells are among the first innate immune cells to elicit early protective immunity that controls invading viral pathogens. The role of the iNKT cell subsets iNKT1, iNKT2, and iNKT17 in herpesvirus immunity remains to be fully elucidated. In this study, we examined the protective role of cornea-resident iNKT cell subsets using the mouse model of ocular herpesvirus infection and disease. Wild-type (WT) C57BL/6 (B6) mice and CD1d knockout (KO) mice were infected ocularly with herpes simplex virus 1 (HSV-1) (strain McKrae). Cornea, spleen, and liver were harvested at 0, 2, 5, 8, and 14 days postinfection (p.i.), and the frequency and function of the three major iNKT cell subsets were analyzed and correlated with symptomatic and asymptomatic corneal herpesvirus infections. The profiles of 16 major pro- and anti-inflammatory cytokines were analyzed in corneal lysates using Western blot and Luminex assays. Early during ocular herpesvirus infection (i.e., day 2), the gamma interferon (IFN-γ)-producing PLZFRORγt (promyelocytic leukemia zinc finger, retinoic acid-related orphan receptor gT) iNKT1 cell subset was the predominant iNKT cell subset in infected asymptomatic corneas. Moreover, compared to the asymptomatic corneas of HSV-1-infected WT mice, the symptomatic corneas CD1d KO mice, with iNKT cell deficiency, had increased levels of the inflammatory cytokine interleukin-6 (IL-6) and decreased levels of IL-12, IFN-γ, and the JAK1, STAT1, NF-κB, and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways. Our findings suggest that IFN-γ-producing PLZFRORγt iNKT1 cells play a role in the protective innate immune response against symptomatic ocular herpes. We investigated the protective role of iNKT cell subsets in asymptomatic ocular herpesvirus infection. We found that early during ocular herpesvirus infection (i.e., on day 2 postinfection), IFN-γ-producing PLZFRORγt iNKT1 cells were the predominant iNKT cell subset in infected corneas of asymptomatic B6 mice (with little to no corneal herpetic disease), compared to corneas of symptomatic mice (with severe corneal herpetic disease). Moreover, compared to asymptomatic corneas of wild-type (WT) B6 mice, the symptomatic corneas of CD1d KO mice, which lack iNKT cells, showed (i) decreases in the levels of IFN-γ and IL-12, (ii) an increase in the level of the inflammatory cytokine IL-6; and (iii) downregulation of the JAK1, STAT1, NF-κB, and ERK1/2 pathways. The findings suggest that early during ocular herpesvirus infection, cornea-resident IFN-γ-producing PLZFRORγt iNKT1 cells provide protection from symptomatic ocular herpes.
天然杀伤 T(iNKT)细胞是最早引发早期保护性免疫的先天免疫细胞之一，这种免疫能够控制入侵的病毒病原体。iNKT 细胞亚群 iNKT1、iNKT2 和 iNKT17 在疱疹病毒免疫中的作用仍有待充分阐明。在这项研究中，我们使用眼部单纯疱疹病毒感染和疾病的小鼠模型，研究了角膜驻留 iNKT 细胞亚群的保护作用。野生型 (WT) C57BL/6 (B6) 小鼠和 CD1d 敲除 (KO) 小鼠通过眼部感染单纯疱疹病毒 1 (HSV-1) (McKrae 株)。在感染后 0、2、5、8 和 14 天 (p.i.) 时采集角膜、脾脏和肝脏，分析三种主要 iNKT 细胞亚群的频率和功能，并与有症状和无症状的角膜单纯疱疹病毒感染相关联。使用 Western blot 和 Luminex 测定法分析角膜裂解物中 16 种主要促炎和抗炎细胞因子的谱。在眼部单纯疱疹病毒感染早期 (即第 2 天)，产生伽马干扰素 (IFN-γ) 的 PLZFRORγt (早幼粒细胞白血病锌指，维甲酸相关孤儿受体 gT) iNKT1 细胞亚群是无症状感染角膜中占优势的 iNKT 细胞亚群。此外，与无症状感染 WT 小鼠的角膜相比，缺乏 iNKT 细胞的有症状感染 CD1d KO 小鼠的角膜中，促炎细胞因子白细胞介素-6 (IL-6) 水平升高，而白细胞介素-12、IFN-γ、JAK1、STAT1、NF-κB 和细胞外信号调节激酶 1/2 (ERK1/2) 途径的水平降低。我们的研究结果表明，产生 IFN-γ的 PLZFRORγt iNKT1 细胞在针对有症状眼部单纯疱疹的保护性先天免疫反应中发挥作用。我们研究了 iNKT 细胞亚群在无症状眼部单纯疱疹病毒感染中的保护作用。我们发现，在眼部单纯疱疹病毒感染早期 (即感染后第 2 天)，与有症状感染小鼠 (严重的角膜疱疹病) 的角膜相比，无症状 B6 小鼠 (仅有很少或没有角膜疱疹病) 的感染角膜中占优势的 iNKT 细胞亚群是产生 IFN-γ的 PLZFRORγt iNKT1 细胞。此外，与 WT B6 小鼠的无症状角膜相比，缺乏 iNKT 细胞的 CD1d KO 小鼠的有症状角膜表现出：(i) IFN-γ和 IL-12 水平降低；(ii) 促炎细胞因子白细胞介素-6 (IL-6) 水平升高；和 (iii) JAK1、STAT1、NF-κB 和 ERK1/2 途径下调。研究结果表明，在眼部单纯疱疹病毒感染早期，角膜驻留的产生 IFN-γ的 PLZFRORγt iNKT1 细胞提供了针对有症状眼部单纯疱疹的保护。
