Targeting Pneumococcal Colonization

肺炎链球菌(Spn，肺炎球菌)仍然是呼吸道的主要病原体 和侵袭性感染。而以壳多糖为基础的疫苗接种有 减少了Spn疾病的高负担，但这种方法未能针对大多数Spn，即 都是非疫苗血清型。不幸的是，更广泛作用的血清型的发展- 事实证明，专注于预防Spn疾病的独立疫苗是难以捉摸的。这个 然而，Spn-宿主相互作用所需的第一步是定植Spn-宿主的粘膜表面 上呼吸道。我们的前提是，中断殖民将会有最大的总体 对脊柱疾病的影响，并为预防提供了新的、尚未探索的可能性。我们已经优化了 一种可应用TN-Seq转座子的Spn定植幼鼠模型 对整个Spn基因组进行询问以确定影响定植的基因座的突变技术。这个 然后将影响定植的非必需Spn基因的完整数据集与 在人类感染期间具有免疫原性的细菌表面因子。在每种情况下都定义了突变体 在幼年和成年小鼠模型中构建和测试了这些候选基因 殖民主义。七个表达修饰细菌表面已知功能的蛋白质的基因座 或根据有效定植所需的宿主底物进行验证。这些蛋白质都是 Spn核心基因组的成员存在于所有菌株中，并显示出最小的序列变异 不同的菌株。我们的假设是，对这些候选人的豁免权，单独或结合在一起，将 中断斯宾人的殖民。这一假设将首先通过重组人免疫来检验。 佐剂(SC或IN)中的蛋白质可最大限度地提高抗体反应。小鼠抗体将被用于 通过体外实验确定其表面定位，并探索其阻断蛋白质功能的能力。 免疫小鼠与单独佐剂对照将在或通过幼崽对幼崽的传播而受到挑战 以评估不同菌株对殖民的保护作用。在未来的研究中，候选人被证实 在小鼠模型中可以使用实验性的人类肺炎球菌携带来研究 从动物试验到人体试验的关键一步。因此，我们的建议采取了一种新颖的方法， 以定居为目标，解决肺炎球菌持续存在的公共卫生问题。

Streptococcus pneumoniae (Spn, the pneumococcus) remains a leading cause of respiratory tract and invasive infection. While vaccination with capsular polysaccharide-based vaccines has decreased the high burden of Spn disease, this approach fails to target the majority of Spn, which are non-vaccine serotypes. Unfortunately, the development of more broadly-acting, serotype- independent vaccines that focus on preventing Spn disease has proven to be elusive. The required first step for Spn-host interaction, however, is colonization of the mucosal surfaces of the upper airways. Our premise is that interrupting colonization will have the greatest overall impact on Spn disease and offers new, unexplored possibilities for prevention. We have optimized an infant mouse model of Spn colonization that has allowed the application of Tn-Seq transposon mutagenesis to interrogate the entire Spn genome to identify loci affecting colonization. The complete dataset of non-essential Spn genes affecting colonization was then compared to bacterial surface factors that are immunogenic during human infection. Defined mutants in each of these candidates were constructed and tested in both infant and adult murine models of colonization. Seven loci expressing proteins of known function that modify the bacterial surface or host substrates were validated as required for efficient colonization. These proteins are all members of the Spn core genome present in all strains and show minimal sequence variation across isolates. Our hypothesis is that immunity to these candidates, alone or in combination, will interrupt Spn colonization. This hypothesis will be tested first by immunization with recombinant protein in adjuvant (SC or IN) to maximize antibody responses. Murine antibody will be used to confirm surface localization and to explore its ability to block protein function using in vitro assays. Immune mice v. adjuvant alone controls will then be challenged IN or via pup-to-pup transmission to assess protection from colonization with diverse strains. In future studies, candidates validated in the murine model can be investigated using experimental human pneumococcal carriage to bridge the critical step from animal to human testing. Thus, our proposal takes a novel approach, targeting colonization, to the ongoing public health problem of the pneumococcus.