Integrated Research Center for Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
Front Immunol. 2021 Sep 8;12:718563. doi: 10.3389/fimmu.2021.718563. eCollection 2021.
CD8+ T cells recognize non-self antigen by MHC class I molecules and kill the target cells by the release of proinflammatory cytokines such as interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α). Our group previously reported an increase of CD8+ T-cell trafficking in the placenta with exposure to Lipopolysaccharides (LPS). CD8+ cytotoxic T cells have been classified into distinct subsets based upon cytokine production: Tc1 cells produce IFN-γ, Tc2 cells produce interleukin 4 (IL-4). Accordingly, the purpose of this research is to analyze the subsets of placenta CD8+ T cells. We hypothesized that LPS injection would induce a change of properties of CD8+ T cell and Tc1/Tc2 ratio. We investigated the subsets of CD8+ T cell infiltration to placenta and their specific function in response to LPS-induced inflammation in a mouse model. At embryonic (E) day 17, pregnant CD-1 dams received an intrauterine injection of 25 µg LPS in100 μl PBS or 100 μl of PBS only. Flow cytometry was used to quantify CD8+ T cells, evaluate the phenotype and subtypes, and detect markers of Tc1 and Tc2 cells in placenta, at 6 hours and 24 hours post injection (hpi). Intracellular staining and flow cytometry were performed to characterize cytokines produced by CD8+ T cells. Standard statistical analysis were employed. After 6 and 24 hours of LPS injection, total CD8 T cells increased (P<0.05). Tc1 cells expanded (P<0.05) in LPS-treated dams compared with the PBS group. The Tc1/Tc2 ratio was significantly higher in the LPS group than the PBS group (P<0.05). The expression of TNF-α and IFN- were increased in LPS group both at 6hpi and 24 hpi (P<0.05). We identified functional placental CD8+ T cell subtypes and found a significant increase ratio of Tc1/Tc2. Following IUI, CD8+ T cells induced inflammatory response in the placenta primarily the production of Type 1 cytokines such as IFN-γ and TNF-α. We have provided evidence of a Tc1-bias response and cytokines in the mouse model of IUI.
CD8+ T 细胞通过 MHC Ⅰ类分子识别非自身抗原，并通过释放炎症细胞因子（如干扰素γ（IFN-γ）和肿瘤坏死因子α（TNF-α））来杀死靶细胞。我们的研究小组先前报道，脂多糖（LPS）暴露会增加胎盘内 CD8+ T 细胞的迁移。根据细胞因子产生情况，CD8+ 细胞毒性 T 细胞已分为不同亚群：Tc1 细胞产生 IFN-γ，Tc2 细胞产生白细胞介素 4（IL-4）。因此，本研究的目的是分析胎盘 CD8+ T 细胞亚群。我们假设 LPS 注射会诱导 CD8+ T 细胞特性和 Tc1/Tc2 比值发生变化。我们在小鼠模型中研究了 LPS 诱导炎症时胎盘 CD8+ T 细胞浸润的亚群及其特定功能。在胚胎（E）第 17 天，妊娠 CD-1 母鼠接受宫内注射 25µg LPS 在 100µl PBS 或仅 100µl PBS。在 LPS 注射后 6 小时和 24 小时，通过流式细胞术定量 CD8+ T 细胞，评估胎盘 CD8+ T 细胞的表型和亚群，并检测 Tc1 和 Tc2 细胞的标志物。通过细胞内染色和流式细胞术分析 CD8+ T 细胞产生的细胞因子。采用标准统计分析。在 LPS 注射后 6 和 24 小时，总 CD8 T 细胞增加（P<0.05）。与 PBS 组相比，LPS 处理组的 Tc1 细胞扩增（P<0.05）。与 PBS 组相比，LPS 组的 Tc1/Tc2 比值明显升高（P<0.05）。在 LPS 组，TNF-α和 IFN-的表达在 6hpi 和 24 hpi 均增加（P<0.05）。我们鉴定了功能性胎盘 CD8+ T 细胞亚群，并发现 Tc1/Tc2 比值显著增加。在 IUI 后，CD8+ T 细胞主要通过产生 IFN-γ和 TNF-α等 1 型细胞因子，在胎盘内诱导炎症反应。我们在 IUI 的小鼠模型中提供了 Tc1 偏向反应和细胞因子的证据。
