DENDRITIC AND T CELLS IN ANTI-BACTERIAL lg RESPONSES

肺炎链球菌（Pn）是一种胞外细菌，是全球发病的主要原因 and mortality.对Pn的系统适应性免疫是由抗体介导的，特别是对Pn特异的IgG。 荚膜多糖（PS），但也用于细菌蛋白质。我们的长期目标是阐明 体内抗PS和抗PS之间存在明显差异的细胞机制 抗蛋白质IG应答完整的Pn，作为开发改进疫苗的先决条件。 与目前基于使用纯化PS抗原的教条相反，IgG抗PS应答是T 不依赖于细胞，我们证明了IgG抗PS对完整Pn的反应在很大程度上依赖于CD 4 + 尽管如此，T细胞在动力学、记忆的产生和免疫功能方面仍然表现出惊人的差异。 树突状细胞和T细胞相对于共同诱导的抗蛋白应答的功能作用。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 功能不同的B细胞亚群的信号传导和/或参与是 区分生理性抗PS和抗蛋白质IG应答。我们将证明，这些 参数差异性地影响：1）响应性B细胞在细胞内的时间区室化， 脾，和2）应答B细胞与其它免疫细胞类型的细胞相互作用。结果我们 将提供一个机制的基础，将阐明所观察到的差异，抗PS和抗蛋白 应答具体目标是： 1.确定B细胞和树突状细胞亚群以及CD 4 + T细胞的性质和关系， 差异介导体内抗PS和抗蛋白质IG同种型对全身免疫的应答 完整的Pn。我们将利用高速电子细胞分选和野生型和非野生型细胞的过继转移。 结合ELISPOT和抗原特异性IG同种型的ELISA分析的遗传改变的免疫细胞 生产，以实现这一目标。 2.确定B细胞、DC和CD 4 + T细胞差异协调的机制 抗PS和抗蛋白质反应的时空背景下。我们将利用来自BCR的B细胞 对Pn衍生的PS或蛋白抗原和来自CD 4 + TCR的T细胞具有IG特异性的敲入小鼠 对Pn衍生蛋白具有特异性的转基因小鼠来实现这一目标。这些细胞将用于 进行脾组织切片的体外功能研究和共聚焦显微镜分析 免疫后。这些研究首次系统地确定了 区分抗PS与抗蛋白质反应的完整细菌，并提供新的基础 immunologic免疫insights见解with direct直接relevance相关to the development发展of anti-bacterial抗bacterial细菌vaccines疫苗.

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 mechanismsthat underlie the distinct differences that exist between in vivo anti-PSand 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 parametersthat 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 thisaim. 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 relevanceto the development of anti-bacterial vaccines.