iNKT and B Cell Cooperation in Immunity and Host Defense

描述（由申请人提供）：不变自然杀伤T细胞（iNKT）是一种脂质特异性淋巴细胞亚群，仅限于非多态性抗原呈递分子CD1d。我们最近证明iNKT细胞可以增强B细胞的体液反应。然而，在对感染性病原体和疫苗抗原的免疫防御过程中，iNKT对B细胞应答的具体作用仍未明确。该建议的总体目标是了解iNKT细胞如何帮助B细胞促进免疫和对多糖疫苗的反应的机制。该建议的工作模型是，iNKT细胞细胞因子产生和反应性的性质和持续时间决定了对糖脂抗原、感染性病原体和基于多糖的疫苗的体液记忆结果。我们对这一假设的基本原理是基于我们之前发表的研究，该研究解剖了iNKT和B细胞对模型糖脂抗原的反应。肺炎链球菌是研究这些相互作用的理想感染模型，因为B细胞和iNKT细胞对肺炎链球菌感染的存活至关重要，基于多糖的肺炎链球菌疫苗刺激的人抗体滴度与NKT细胞数量相关，而且，尽管引入了有效的蛋白质结合多糖疫苗，肺炎链球菌仍然是一个主要的公共卫生威胁，每年造成近50万儿童死亡。我们将分三步实现我们的目标：在Aim1中，我们将利用混合骨髓嵌合体、FACS分析、共聚焦成像和血清抗体ELISA/ elispot来确定细胞类型特异性细胞因子对iNKT细胞支持的体液记忆的贡献持续时间。在目的2中，我们将应用相同的技术来解剖iNKT细胞效应功能，负责在感染期间驱动抗原特异性体液B细胞的结果。最后，在aims中，我们将结合ELISA和ELISPOT方法研究肺炎链球菌多糖疫苗和新的纳米颗粒配方，以确定inkt配体作为疫苗佐剂的潜力。重要的是，我们期望通过了解同源和非同源iNKT细胞在针对糖脂抗原、细菌感染和基于多糖的疫苗的免疫应答过程中帮助B细胞的机制，我们将能够更好地利用这些细胞来改善免疫防御和开发针对许多不同人类病原体的疫苗。这些发现预计将对未来开发一种全新的、inkt导向的疫苗策略产生重要的积极影响，这种疫苗策略将是现有疫苗方法的补充，并且鉴于CD1d的非多态性性质，将对所有人普遍有效。

DESCRIPTION (provided by applicant): Invariant Natural Killer T (iNKT) cells are a lipid-specific lymphocyte subset restricted to the non-polymorphic antigen presenting molecule CD1d. We recently demonstrated that iNKT cells can enhance B cell humoral responses. However, the specific contribution of iNKT help for B cell responses during immune defense against infectious pathogens and vaccine antigens remains largely undefined. The overall objective of this proposal is to understand the mechanism of how iNKT cells help B cells to promote both immunity and the response to polysaccharide-based vaccines. The working model for this proposal is that the nature and duration of iNKT cell cytokine production and reactivity dictate the humoral memory outcome in response to glycolipid antigens, infectious pathogens, and polysaccharide-based vaccines. Our rationale for this hypothesis is based on our previously published studies dissecting iNKT and B cell cooperation in response to model glycolipid antigens. Streptococcus pneumoniae is the ideal infection model for investigating these interactions because both B cells and iNKT cells are critical for survival from S. pneumoniae infection, human antibody titers stimulated by polysaccharide-based S. pneumoniae vaccines correlate with NKT cell numbers, and, despite the introduction of effective protein-conjugate polysaccharide vaccines, S. pneumoniae remains a major public health threat responsible for the deaths of nearly half a million children each year. We will achieve our objective in three steps: In Aim1 we will utilize mixed bone marrow chimeras, FACS analysis, confocal imaging, and serum antibody ELISA/ELISPOTs to identify the duration of cell-type specific cytokine contributions to iNKT cell supported humoral memory. In Aim2, we will apply the same techniques to dissect the iNKT cell effector functions responsible for driving antigen-specific humoral B cell outcomes during infection. Finally, in Aim3 we will couple ELISA and ELISPOT approaches to studies with S.pneumoniae polysaccharide-based vaccines and a new nanoparticle formulation to define the potential for an-iNKT ligand to serve as a vaccine adjuvant. Importantly, we expect that by learning the mechanisms of cognate and non- cognate iNKT cell help for B cells during immune responses against glycolipid antigens, bacterial infection, and polysaccharide-based vaccines we will be better able to exploit these cells for improved immune defense and vaccine development against many different human pathogens. These findings are expected to have an important positive impact by informing future development of an entirely new, iNKT-directed, vaccine strategy which would be complementary for existing vaccine approaches and, given the non-polymorphic nature of CD1d, would be universally effective in all people.