Immunology Unit, Department of Biomedical Sciences, Medical School, University of Barcelona, Barcelona, Spain.
IrsiCaixa AIDS Research Institute, Badalona, Spain, Germans Trias i Pujol Research Institute (IGTP), Catalonia, Spain.
Front Immunol. 2021 Apr 23;12:666545. doi: 10.3389/fimmu.2021.666545. eCollection 2021.
In genetically prone individuals, chronic immune activation may lead to expansion of autoreactive lymphocyte clones that can induce organ damage developing autoimmune disorders. Sjögren's Syndrome (SjS) is a systemic chronic autoimmune disease that primarily affects exocrine glands. Despite the accumulated evidences of profound B-cell alterations of humoral immunity, the repertoire and development of B-cell autoreactivity in SjS remains to be determined. We hypothesize that SjS mice will have an increased frequency of self-reactive B cells with a progressive evolution to antigen-driven oligoclonality. Here, we study the B cell repertoire of NOD.H-2 mice, a mouse model of spontaneous autoimmunity mimicking SjS without developing diabetes. A library of 168 hybridomas from NOD.H-2 mice and 186 C57BL/6J splenocytes at different ages was created. The presence of mono or polyreactive autoantibodies to several antigens was evaluated by ELISA, and their staining patterns and cellular reactivity were tested by IFA and FACS. We observed a higher frequency of autoreactivity among B-cell clones from NOD.H-2 mice as compared to wild-type mice. The presence of polyreactive and autoreactive IgG clones increased with mice age. Strikingly, all anti-Ro52 autoantibodies were polyreactive. No loss of polyreactivity was observed upon antibody class switching to IgG. There was a progression to oligoclonality in IgG B cells with mice aging. Our results indicate that in the NOD.H-2 mouse model of SjS, IgG+ B cells are mainly polyreactive and might expand following an unknown antigen-driven positive selection process.
在遗传易感性个体中，慢性免疫激活可能导致自身反应性淋巴细胞克隆的扩增，从而诱导器官损伤，发展为自身免疫性疾病。干燥综合征（SjS）是一种全身性慢性自身免疫性疾病，主要影响外分泌腺。尽管体液免疫中 B 细胞改变的证据很多，但 SjS 中 B 细胞自身反应性的 repertoire 和发展仍有待确定。我们假设 SjS 小鼠将具有更高频率的自身反应性 B 细胞，并且这些 B 细胞具有进行抗原驱动的寡克隆性演变的趋势。在这里，我们研究了 NOD.H-2 小鼠的 B 细胞 repertoire，NOD.H-2 小鼠是一种自发性自身免疫模型，模拟 SjS 但不发展为糖尿病。创建了来自 NOD.H-2 小鼠和不同年龄的 C57BL/6J 脾细胞的 168 个杂交瘤和 186 个文库。通过 ELISA 评估了单克隆或多克隆自身抗体针对多种抗原的存在，并通过 IFA 和 FACS 测试了其染色模式和细胞反应性。与野生型小鼠相比，我们观察到 NOD.H-2 小鼠的 B 细胞克隆中自身反应性的频率更高。随着小鼠年龄的增长，多反应性和自身反应性 IgG 克隆的存在增加。引人注目的是，所有抗 Ro52 自身抗体均为多反应性。在抗体类别转换为 IgG 时，未观察到多反应性丧失。随着小鼠年龄的增长，IgG+B 细胞出现寡克隆性。我们的结果表明，在 SjS 的 NOD.H-2 小鼠模型中，IgG+B 细胞主要是多反应性的，并且可能在未知的抗原驱动的阳性选择过程后扩增。
