调节性B细胞在急性肺损伤中的免疫负调控作用和机制研究

Regulatory B cells (Bregs) are a subset of B cells with potent immunosuppressive activity, which were found recently. Immune negative regulation plays a key role in the repair phase of acute lung injury(ALI)/acute respiratory distress syndrome(ARDS), previous studies on which have been focus on regulatory T cells (Tregs),while the role of Bregs in it is not clear yet.In our preliminary studies, we have found that in LPS-induced ALI model, B cell-deficient mice exhibited a more severe lung injury than wild-type mice. In addition, we have identified a population of IL-10-producing B cells in the lungs from both ALI mice and patients. These suggest that Bregs may be involved in the development and progression of ALI. Therefore, this study will use wild type and specific gene deficiency ALI mice model, adoptive transfer Bregs cell, apply with MicroCT, Flowcytometry,as well as Elispot techniques,to examine the responding features and immune regulatory roles of Bregs in murine ALI model, to elucidate the effects and underlying mechanisms of Bregs on M2 macrophage and Tregs differentiation, also to explore the clinical significance of bronchoalveolar lavage Bregs in ARDS patients, aiming to elucidate the negative regulatory role and mechanism of Bregs in ALI/ARDS, and provide novel clues for ALI/ARDS treatment.

调节性B细胞（Bregs）是近来发现的一类具有抑制功能的免疫负性调控细胞。免疫负调控在急性肺损伤（ALI）/ARDS修复过程中发挥重要作用，但已有研究主要集中于调节性T细胞（Tregs），而Bregs在其中的作用未知。课题组前期研究发现：在脂多糖诱导的ALI模型中，B细胞缺失小鼠比野生型小鼠肺损伤程度严重，并且在ALI小鼠和患者肺组织存在一群分泌IL-10的调节性B细胞，提示Bregs参与了ALI的发生发展。因此，本课题拟采用野生型及特定基因缺失ALI小鼠模型，受体小鼠经气道注入Bregs细胞。应用MicroCT、流式细胞、Elispot等技术，进行ALI模型Bregs的应答特征和免疫调节功能、Bregs对M2型巨噬细胞和调节性T细胞诱导分化及ARDS患者支气管肺泡灌洗液Bregs的临床意义研究，阐明Bregs在ALI/ARDS中的免疫负调控作用和机制，为ALI/ARDS治疗提供新的思路。

急性肺损伤（Acute lung injury, ALI）/急性呼吸窘迫综合征（Acute respiratory distress syndrome, ARDS）是各种直接（如肺炎、肺钝挫伤等）和间接（如脓毒症、创伤等）原因引起的威胁生命的临床综合症，是导致ICU患者死亡的主要原因之一。免疫负调控在急性肺损伤ALI/ARDS修复过程中发挥重要作用，调节性B细胞（Bregs）是近来发现的一类具有抑制功能的免疫负性调控细胞，而Bregs在其中的作用未知。课题组前期研究发现：在脂多糖诱导的ALI模型中，B细胞缺失小鼠比野生型小鼠肺损伤程度严重，并且在ALI小鼠和患者肺组织存在一群分泌IL-10的调节性B细胞，提示Bregs参与了ALI的发生发展。本课题采用野生型及特定基因缺失ALI小鼠模型，受体小鼠经气道注入Bregs细胞，应用流式细胞分析及分选、细胞共培养等技术，进行ALI模型Bregs的应答特征和免疫调节功能、Bregs对M2型巨噬细胞和调节性T细胞诱导分化及ARDS患者支气管肺泡灌洗液Bregs的临床意义研究，研究发现野生型小鼠肺组织和肺泡灌洗液（Bronchoalveolar Lavage Fluid, BALF）Bregs在ALI/ARDS第1天升高持续到第7天，Bregs细胞分泌的IL-10在ALI小鼠模型起保护作用，Bregs在LPS刺激下诱导M0单核细胞向M2型巨噬细胞分化并可诱导T细胞向调节性T细胞分化，ARDS患者支气管肺泡灌洗液Bregs在第1天即升高。本研究的完成将阐明Bregs在ALI/ARDS中的免疫负调控作用和机制，并为Bregs在ALI/ARDS治疗提供新的思路。