Pneumococcal immunization through a novel mechanism

衣壳多糖-蛋白质结合疫苗在预防侵袭性疾病方面是有效的 包括的血清型的肺炎链球菌(肺炎球菌)，但制造和管理成本很高， 对中耳炎最低限度有效，并接受血清型替换(其中未包括 血清型变得更加普遍)。因此，需要新的免疫方法。 我们意外地发现，小鼠鼻腔免疫肺炎球菌细胞壁多糖。 (CWPS，所有血清型的共同抗原)对鼻咽定植产生持久的抵抗力 中耳感染不同血清型肺炎球菌。引人注目的是，疫苗的保护作用(即 CWPS+粘膜佐剂)不依赖于抗体，依赖于CD4+T细胞的存在。 这种多糖诱导的细胞介导的粘膜免疫，可抵抗“细胞外”的定植。 据我们所知，被包裹的细菌以前没有被证明过，因此代表着 一种接种疫苗的新方法。 我们假设，CWPS的两性离子特性在诱导这种T细胞依赖的过程中是关键的 回应。我们的第一个目标是通过进一步纯化来确定CWPS保护的结构基础， 聚合物合成、化学修饰以改变两性离子基序、自动偶联或偶联为 蛋白质载体。因此，或者两性离子假说将被证实和/或最小保护结构 将会被定义。其次，我们将更详细地研究CD4+T细胞赋予 对肺炎球菌定植的保护。采用迁移实验将表征的性质 保护性T细胞反应。进一步的方法将包括通过使用以下方法极化T细胞反应 基因敲除小鼠或给予细胞因子、中性粒细胞耗竭实验和组织病理学 共聚焦显微镜。在第三个目标中，我们将评估先天免疫反应在调节 利用Toll样受体(TLR)基因敲除小鼠和联合给药获得对定植的免疫力 免疫时作为佐剂的TLR配体。 我们的研究将增加对肺炎球菌定植免疫的基本了解，并可能导致 一种简单的、明确的、可能的合成疫苗，将补充或取代多价胶囊 结合疫苗接种这种儿童的高度流行的病原体。

The capsular polysaccharide-protein conjugate vaccine is effective in prevention of invasive disease by Streptococcus pneumoniae (pneumococci) of the serotypes included but is costly to make and administer, minimally effective against otitis media, and subject to serotype replacement (in which non-included serotypes become more prevalent). Therefore, novel approaches to immunization are needed. We found unexpectedly that mice immunized intranasally with the pneumococcal cell wall polysaccharide (CWPS, an antigen commonto all serotypes) develop long-lasting resistance to nasopharyngeal colonization and middle ear infection with pneumococci of different serotypes. Strikingly, protection by the vaccine(i.e. CWPS + mucosal adjuvant) is independent of antibody and dependent on the presence of CD4+ T cells. This polysaccharide-induced, cell-mediated mucosal immunity against colonization by an "extracellular" encapsulated bacterium has not, to our knowledge, been previously demonstrated and therefore represents a novel approachto vaccination. We hypothesize that the zwitterionic property of CWPS is critical in eliciting this T-cell-dependent response. Our first goal is to determine the structural basis of protection by CWPS by further purification, polymer synthesis, chemical modifications to alter the zwitterionic motif, auto-coupling, or coupling to a protein carrier. Thus either the zwitterion hypothesis will be confirmed and/or the minimal protective structure will be defined. Secondly, we will examine in more detail the mechanisms whereby CD4+ T cells confer protection against pneumococcal colonization. Adoptive transfer experiments will characterize the nature of the protective T cell responses. Further approaches will include polarization of T cell responses by use of knockout mice or administration of cytokines, neutrophil depletion experiments, and histopathology with confocal microscopy. In a third aim, we will evaluate the role of innate immune responses in modulating acquired immunity to colonization, by use of Toll-like receptor (TLR) knockout mice and co-administration of TLR ligands as adjuvants at the time of immunization. Our studies will increase basic understanding of immunity to pneumococcal colonization and could lead to a simple, defined, and possibly synthetic vaccine that would complement or replace the multivalent capsular conjugates in vaccination against this, highly prevalent pathogen of children.