Enhancing neonatal immunity to Streptococcus pneumoniae

描述（由申请人提供）：拟议研究的总体目标是评估婴儿对候选肺炎球菌疫苗的免疫反应。Malley实验室和其他地方的调查已经揭示了CD4+ T细胞在提供对肺炎球菌定植的保护中的作用。Malley实验室开发的全细胞疫苗（WCV）将进入I期临床试验，可提供双管齐下的抗肺炎球菌保护：CD4+ th17依赖的抗定菌保护和非荚膜抗体介导的抗侵袭性疾病保护。初步研究表明，虽然幼鼠对全细胞疫苗有反应，并对肺炎球菌定植有保护，但与成年小鼠相比，它们的CD4+ T细胞反应和保护较低。了解抑制婴儿对WCV强烈T细胞反应的因素将有助于指导更高免疫原性疫苗和佐剂的开发，并为临床试验中的免疫学评估提供信息。IL-10是Th17反应的有效抑制剂，我们已经证明新生儿巨噬细胞在响应肺炎球菌抗原刺激时比成年小鼠巨噬细胞产生更多的IL-10。因此，我们提出验证婴儿WCV免疫原性和疗效降低的假设，主要是由于新生儿抗原提呈细胞增加了IL-10和其他抑制性细胞因子的产生。在Aim 1中，我们将使用转基因小鼠和Horwitz实验室开发的独特IL-10试剂的组合来确定新生儿巨噬细胞产生的IL-10是否会减弱疫苗接种后的保护性Th17反应。在目的2中，我们将通过比较细胞内NF-?来确定新生儿巨噬细胞产生IL-10水平升高的原因。B和ERK信号通路，以及细胞外IFN-¿/IL-27轴参与调节IL-10的产生。在第三个也是最后一个目标中，这些先天和获得性免疫反应将在非人灵长类动物模型中进行评估。我们将研究新生、年轻和成年恒河猴的巨噬细胞反应，这将提供关于肺炎球菌和这种疫苗的先天免疫反应性质的重要信息。新生儿、幼崽和成年恒河猴接种GMP级全细胞疫苗，并详细分析其免疫反应（T细胞和抗体）。总的来说，这些研究将为婴儿与成人对候选肺炎球菌疫苗的免疫反应提供重要的见解，并将指导该疫苗进入临床试验后的进一步研究。

DESCRIPTION (provided by applicant): The overall objective of the proposed research is to evaluate the immunological response of infants to a candidate pneumococcal vaccine. Investigations in the Malley laboratory and elsewhere have revealed the role of CD4+ T cells in providing protection against pneumococcal colonization. The whole cell vaccine (WCV) developed in the Malley laboratory, which will be entering Phase I clinical trials, confers a two-pronged protection against pneumococcus: CD4+ Th17-dependent protection against colonization and non-capsular antibody-mediated protection against invasive disease. Preliminary studies have shown that while infant mice respond to the whole cell vaccine and are protected against pneumococcal colonization, they nevertheless have a reduced CD4+ T cell response and lower protection when compared to adult mice. Understanding the factors that inhibit a robust T cell response to WCV in infants will help guide development of more highly immunogenic vaccines and adjuvants, and inform immunological assessment during clinical trials. IL-10 is a potent inhibitor of Th17 responses, and we have shown that neonatal macrophages make significantly more IL-10 in response to stimulation with pneumococcal antigen than macrophages from adult mice. Therefore we propose to test the hypothesis that reduced immunogenicity and efficacy of WCV in infants is primarily due to increased production of IL-10 and other inhibitory cytokines by neonatal antigen presenting cells. In Aim 1 we will use a combination of transgenic mice and unique IL-10 reagents developed in the Horwitz laboratory to determine whether IL-10 produced by neonatal macrophages attenuates the protective Th17 response following vaccination. In Aim 2 we will determine why neonatal macrophages produce enhanced levels of IL-10 by comparing the intracellular NF-?B and ERK signaling pathways, as well as the extracellular IFN-¿/IL-27 axis that have been implicated in regulating IL-10 production. In the third and final aim, these innate and acquired immune responses will be evaluated in a nonhuman primate model. We will examine the macrophage response in neonatal, young and adult rhesus macaques, which will provide important information regarding the nature of the innate immune response to pneumococcus and this vaccine in particular. Neonatal, young and adult rhesus macaques will be immunized with Good Manufacturing Practice (GMP)-grade whole cell vaccine and their immune (T cell and antibody) responses analyzed in detail. Overall, these investigations will provide important insight into the immune response to a candidate pneumococcal vaccine in infants vs. adults and will guide further studies of this vaccine as it enters clinical trials.