B1 Cell Induction of TH17 Cell Differentiation

描述(由申请人提供)：Th17细胞代表最近发现的T淋巴细胞辅助亚群，它是促炎的，参与了自身免疫性营养不良的发病机制。B1细胞是一种独特的B淋巴细胞系，也是免疫系统的基本组成部分，负责产生天然免疫球蛋白。该实验室最近发表的研究表明，B1细胞在刺激NAOVE T细胞分化为Th17细胞方面独一无二地有效，而B2细胞在这方面做得很差或根本没有。这项建议及其以后的长期目标是从B细胞/T细胞相互作用的角度阐明B1细胞在免疫系统中的作用和功能。本文描述的工作目标与B1细胞诱导Th17细胞分化的非凡能力有关。其具体目的是：1)通过检测细胞因子和维甲酸的潜在作用、用重组蛋白补充B/T细胞以及通过中和抗体和基因敲除动物降低细胞因子水平，来确定当B2细胞不能诱导Th17细胞分化时，B1细胞如何有效地发挥作用；2)通过评估B7家族成员，特别是CD80、CD86和PD-L2的潜在作用(通过中和抗体和基因敲除动物减少B7共刺激相互作用)，以及通过构建逆转录病毒转导的骨髓嵌合体来部分替换缺陷小鼠的B7家族成员，确定当B2细胞不能诱导Th17细胞分化时，B1细胞如何有效地发挥作用；3)通过过继转移到B细胞和OVA多肽和蛋白缺陷小鼠的OVA特异性OT-II T细胞，测试B1细胞在产生Th17细胞分化中的体内活性。本研究的结果有望为了解B1细胞的功能和诱导Th17细胞分化的因素提供新的信息，并证明B1细胞在体内可以指导T细胞的分化。该项目产生的结果将阐明B1细胞和Th17细胞之间新的和意想不到的联系，进一步了解B1细胞在与T细胞相互作用中的作用，并反映B1细胞在免疫系统中的位置和活动。就后者而言，这里描述的工作可能描绘出B细胞的新角色，其中不同的B细胞谱系驱动特定的T细胞极化，将B细胞作为T细胞功能的导演/管理者。阐明这些点可能会提供新的靶点和策略来改善自身免疫性营养不良的进展。公共卫生相关性：Th17细胞是最近发现的一种T淋巴细胞亚群，可产生炎症，与自身免疫性疾病密切相关。B1细胞是B淋巴细胞的一个亚群，特别有价值，因为它们在不需要接种疫苗的情况下产生抗病抗体，但它们存在问题，因为它们也像一些T细胞一样，与自身免疫性疾病有关。这项提案中描述的工作建立在一项新发现的基础上，即B1细胞特别擅长激活Th17细胞产生炎症。该项目概述的工作旨在更多地了解B1细胞的这一新功能，通过找出B1细胞在刺激静止T细胞成为炎性Th17细胞方面如此有效的原因，通过确定B1细胞诱导的炎性Th17细胞是否参与产生自身免疫，以及通过在动物模型中衡量B1细胞产生炎性Th17细胞的能力。这些研究将提供关于如何调节体内炎症细胞数量的信息；这些信息可能会对自身免疫治疗类风湿性关节炎等疾病有用。

DESCRIPTION (provided by applicant): Th17 cells denote a recently identified T lymphocyte helper subset that is proinflammatory and is involved in the pathogenesis of autoimmune dyscrasias. B1 cells represent a distinct B lymphocyte lineage and fundamental component of the immune system that is responsible for the production of natural immunoglobulin. Recent published work from this laboratory has shown that B1 cells are uniquely efficient in stimulating naove T cells to differentiate into Th17 cells, whereas B2 cells do so only poorly or not at all. The long term objective of this proposal and beyond is to elucidate the role and function of B1 cells within the immune system in terms of B cell/T cell interaction. The goals of the work described herein relate to the remarkable capacity of B1 cells to induce Th17 cell differentiation. The specific aims are to 1) Determine how B1 cells function effectively to induce Th17 cell differentiation when B2 cells do not, by evaluating the potential role of cytokines and retinoic acid, through assay of supernatants by ELISA, supplementation of B/T cultures with recombinant proteins, and reduction of cytokine levels via neutralizing antibodies and knock-out animals; 2) Determine how B1 cells function effectively to induce Th17 cell differentiation when B2 cells do not, by evaluating the potential role of B7 family members, specifically CD80, CD86, and PD-L2, through reduction of B7 co-stimulatory interactions via neutralizing antibodies and knock-out animals, and by partial replacement of B7 family members in deficient mice through construction of retrovirally transduced bone marrow chimeras; 3) Test the in vivo activity of B1 cells in producing Th17 cell differentiation using OVA-specific OT-II T cells adoptively transferred to Class II-deficient mice along with B cells and OVA peptide and protein. The results of this study are expected to provide new information about the function of B1 cells and new information about the factors that induce Th17 cell differentiation, as well as demonstrate that B1 cells can direct T cell differentiation in vivo. The results generated as a result of this project will illuminate the new and unexpected connection between B1 cells and Th17 cells, furthering knowledge of the role of B1 cells during interaction with T cells and reflecting on the place and activity of B1 cells within the immune system. In terms of the latter, the work described here may delineate a new role for B cells wherein distinct B cell lineages drive specific T cell polarization, placing B cells as the directors/managers of T cell function. Elucidation of these points is likely to provide new targets and strategies to ameliorate the progression of autoimmune dyscrasias. Public Health Relevance: Th17 cells are a recently discovered subpopulation of T lymphocytes that produces inflammation and that is intimately involved in autoimmune diseases. B1 cells are a subpopulation of B lymphocytes that are especially valuable because they produce disease-fighting antibody without the need for vaccination, but they are problematical because they too, like some T cells, are involved in autoimmune diseases. The work described in this proposal builds on the new discovery that B1 cells are especially good at activating Th17 cells to produce inflammation. The work outlined in this project is designed to learn more about this new function of B1 cells, by figuring out why B1 cells are so effective in stimulating resting T cells to become inflammatory Th17 cells, by determining whether B1 cell-induced inflammatory Th17 cells are involved in producing autoimmunity, and by gauging the ability of B1 cells to produce inflammatory Th17 cells in animal models. These studies will provide information on how to regulate the number of inflammatory cells in the body; this information might then be useful in autoimmune treating diseases like rheumatoid arthritis.