Background. This study is aimed at exploring the role of B7-H4 in the pathogenesis of primary Sjögren’s syndrome (pSS) in NOD/Ltj mouse. Methods. B7-H4 expression in salivary glands was examined by IHC, and lymphocyte infiltration was showed by H&E. Next, anti-B7-H4 mAb or immunoglobulin isotype was injected into NOD/Ltj mice. Cytokine levels were measured by quantitative RT-PCR, and immunoglobulins were measured by ELISA. T cell subsets were analyzed by flow cytometry. Last, we treated NOD/Ltj mice with B7-H4Ig and control Ig. CD4+Foxp3+ T cells were assessed by immunohistochemistry. Two-tailed Student’s -tests were used to detect the statistical difference in various measures between the two groups. Results. B7-H4 expression was remarkably reduced in salivary glands of NOD/Ltj mice at 15 weeks compared with the NOD/Ltj mice at 8 weeks. Anti-B7-H4 mAb treatment increased lymphocyte infiltration in salivary glands. Inflammatory cytokines including IL-12, IL-18, IL-1α, TNF-α, IFN-α, and BAFF were upregulated markedly in anti-B7-H4 mAb-treated mice compared to IgG isotype-treated mice. Flow cytometry analysis showed that anti-B7-H4 mAb-treated mice had lower levels of CD4+Foxp3+/CD4+ T cells in spleen. Moreover, Foxp3 mRNA levels of salivary glands were diminished in anti-B7-H4 mAb-treated mice. Flow cytometry analysis showed that anti-B7-H4 mAb inhibited CD4+Foxp3+/CD4+ T cell production, while B7-H4Ig would promote naïve CD4+ T into Treg differentiation. Administration with B7-H4Ig displayed significantly decreased lymphocyte infiltration in salivary glands and low levels of total IgM and IgG in serum. Analysis of inflammatory cytokines in salivary glands after B7-H4Ig treatment revealed that the mRNA levels of IL-12, IL-6, IL-18, IL-1α, TNF-α, and IFN-α were significantly downregulated in B7-H4Ig-treated mice compared to control Ig treatment. B7-H4Ig-treated mice had significantly higher levels of CD4+Foxp3+/CD4+ T cells in spleen. IHC in salivary gland revealed that CD4+Foxp3+ T cells of B7-H4Ig treatment mouse were more than control Ig treatment. Conclusions. Our findings implicate that B7-H4 has a protective role for salivary gland epithelial cells (SGECs) and therapeutic potential in the treatment of pSS.

中文翻译：

---

B7-H4 通过调节 NOD/Ltj 小鼠的 Treg 分化抑制原发性干燥综合征的发展

背景。本研究旨在探讨 B7-H4 在 NOD/Ltj 小鼠原发性干燥综合征 (pSS) 发病机制中的作用。方法。IHC检测唾液腺中B7-H4的表达，H&E显示淋巴细胞浸润。接下来，将抗 B7-H4 mAb 或免疫球蛋白同种型注射到 NOD/Ltj 小鼠中。细胞因子水平通过定量 RT-PCR 测量，免疫球蛋白通过 ELISA 测量。通过流式细胞术分析 T 细胞亚群。最后，我们用 B7-H4Ig 和对照 Ig 治疗 NOD/Ltj 小鼠。通过免疫组织化学评估 CD4+Foxp3+ T 细胞。双尾学生检验用于检测两组之间各种测量的统计差异。结果. 与 8 周时的 NOD/Ltj 小鼠相比，15 周时 NOD/Ltj 小鼠唾液腺中 B7-H4 的表达显着降低。抗 B7-H4 mAb 治疗增加了唾液腺中的淋巴细胞浸润。炎性细胞因子包括 IL-12、IL-18、IL- 1α、TNF - α、IFN- α和 BAFF 在抗 B7-H4 mAb 治疗的小鼠中与 IgG 同种型治疗的小鼠相比显着上调。流式细胞术分析显示，抗 B7-H4 mAb 治疗的小鼠脾脏中 CD4+Foxp3+/CD4+ T 细胞水平较低。此外，在抗 B7-H4 mAb 处理的小鼠中，唾液腺的 Foxp3 mRNA 水平降低。流式细胞术分析表明，抗 B7-H4 mAb 抑制 CD4+Foxp3+/CD4+ T 细胞的产生，而 B7-H4Ig 会促进幼稚 CD4+ T 分化为 Treg。B7-H4Ig 给药显示唾液腺淋巴细胞浸润显着降低，血清中总 IgM 和 IgG 水平低。B7-H4Ig处理后唾液腺炎性细胞因子分析显示IL-12、IL-6、IL-18、IL- 1α、TNF - α和IFN-与对照 Ig 治疗相比，在 B7-H4Ig 治疗的小鼠中，α显着下调。B7-H4Ig 处理的小鼠脾脏中的 CD4+Foxp3+/CD4+ T 细胞水平显着升高。唾液腺 IHC 显示 B7-H4Ig 治疗小鼠的 CD4+Foxp3+ T 细胞多于对照 Ig 治疗。结论。我们的研究结果表明，B7-H4 对唾液腺上皮细胞 (SGEC) 具有保护作用，并在治疗 pSS 中具有治疗潜力。