DENDRITIC AND T CELLS IN ANTI-BACTERIAL lg RESPONSES

树突状细胞和 T 细胞在抗细菌 lg 反应中的作用

• 批准号: 7103213
• 负责人: CLIFFORD M SNAPPER
• 金额: $ 34.09万
• 依托单位: HENRY M. JACKSON FDN FOR THE ADV MIL/MED
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7103213
• 关键词: CD40 molecule; MHC class II antigen; Streptococcus pneumoniae; antibacterial antibody; antibody formation; antigen presentation; bacterial antigens; bactericidal immunity; cellular immunity; cytokine; dendritic cells; helper T lymphocyte; laboratory mouse; protein biosynthesis; tissue /cell culture

DESCRIPTION (provided by applicant): Streptococcus pneumoniae (Pn) is an extracellular bacterium that is a major cause of global morbidity and mortality. Systemic adaptive immunity to Pn is mediated by antibody, especially IgG specific for the capsular polysaccharide (PS), but also for bacterial proteins. Our long-term goal is to elucidate the cellular mechanisms that underlie the distinct differences that exist between in vivo anti-PS and anti-protein Ig responses to intact Pn, as a prerequisite to the development of improved vaccines. In contrast to the current dogma, based on using purified PS antigens, that IgG anti-PS responses are T cell-independent, we demonstrated that the IgG anti-PS response to intact Pn is heavily dependent on CD4+ T cells but nevertheless, still exhibits striking differences in kinetics, generation of memory, and the functional roles of dendritic and T cells relative to the co-induced anti-protein response. In light of these data, the central hypothesis that underlies our proposed research is that differential B cell receptor signaling and/or involvement of functionally distinct B cell subsets are the key parameters that distinguish physiologic anti-PS and anti-protein Ig responses. We will demonstrate that these parameters differentially impact on 1) the temporal compartmentalization of responding B cells within the spleen, and 2) the cellular interactions of the responding B cells with other immune cell types. As a result we will provide a mechanistic basis that will elucidate the observed differences in anti-PS and anti-protein responses. The specific aims are to: 1. Determine the nature and relationships of B cell and dendritic cell subsets, and CD4+ T cells that differentially mediate in vivo anti-PS and anti-protein Ig isotype responses to systemic immunization with intact Pn. We will utilize high speed electronic cell sorting and adoptive transfer of wild-type and genetically altered immune cells combined with ELISPOT and ELISA analyses of antigen-specific Ig isotype production to accomplish this aim. 2. Determine the mechanism by which B cells, DCs, and CD4+ T cells differentially orchestrate anti-PS and anti-protein responses within a spatiotemporal context. We will utilize B cells from BCR knock-in mice with Ig specificity for Pn-derived PS or protein antigens and T cells from CD4+ TCR transgenic mice with specificity for a Pn-derived protein to accomplish this aim. These cells will be used to conduct in vitro functional studies and confocal microscopic analyses of splenic tissue sections post-immunization. These studies are the first to systematically determine the mechanisms that distinguish anti-PS from anti-protein responses to an intact bacterium and provide novel basic immunologic insights with direct relevance to the development of anti-bacterial vaccines.

描述（由申请人提供）：肺炎链球菌（PN）是一种细胞外细菌，是全球发病率和死亡率的主要原因。对PN的全身适应性免疫是由抗体介导的，尤其是针对囊囊多糖（PS）的IgG，但也针对细菌蛋白。我们的长期目标是阐明体内抗PS与完整PN的抗蛋白Ig反应之间存在明显差异的细胞机制，这是改善疫苗的发展的先决条件。 In contrast to the current dogma, based on using purified PS antigens, that IgG anti-PS responses are T cell-independent, we demonstrated that the IgG anti-PS response to intact Pn is heavily dependent on CD4+ T cells but nevertheless, still exhibits striking differences in kinetics, generation of memory, and the functional roles of dendritic and T cells relative to the co-induced anti-protein response.鉴于这些数据，我们提出的研究基础的中心假设是，差异B细胞受体信号传导和/或功能上不同的B细胞亚群的参与是区分生理抗PS和抗蛋白Ig反应的关键参数。我们将证明这些参数对1）脾内反应B细胞的时间分室化差异，以及2）反应B细胞与其他免疫细胞类型的细胞相互作用。结果，我们将提供一个机械基础，以阐明抗PS和抗蛋白质反应的观察到的差异。具体目的是：1。确定B细胞和树突状细胞子集的性质和关系，以及在体内抗PS中差异介导的CD4+ T细胞，以及抗蛋白质Ig同种型对系统性免疫的抗蛋白质Ig同种型响应，对系统性免疫使用完整的PN。我们将利用野生型和遗传改变的免疫细胞和ELISPOT和ELISA分析抗原特异性Ig同型产生的分析的高速电子细胞分类和遗传改变的免疫细胞的产物转移。 2。确定B细胞，DC和CD4+ T细胞在时空环境中差异地编排抗PS和抗蛋白质反应的机制。我们将利用具有Ig特异性的BCR敲入小鼠的B细胞对PN衍生的PS或蛋白质抗原和T细胞的CD4+ TCR转基因小鼠的T细胞具有特异性，以实现PN衍生的蛋白质来实现这一目标。这些细胞将用于进行体外功能研究和免疫后脾组织切片的共聚焦显微镜分析。这些研究是第一个系统地确定抗PS与抗蛋白质对完整细菌的反应的机制，并提供了与抗细菌疫苗的发展直接相关的新型基本免疫学见解。