Using combination adjuvants to direct and control immune responses at the intestinal mucosa

 描述(申请人提供)：大多数病原体通过粘膜表面进入人体，然而，到目前为止，大多数获得许可的疫苗都是非肠道注射，主要是肌肉注射。虽然它们在诱导系统免疫方面很出色，但并不总是诱导所需的粘膜免疫反应。这突显了我们在理解免疫如何被操纵以引起粘膜免疫反应以及如何利用这些知识来创造更好的黏膜病原体疫苗方面的差距。确定佐剂在这种反应中所起的作用是开发这种疫苗的关键；然而，决定佐剂驱动的粘膜抗体和细胞免疫反应的机制还不是很清楚。我们用主要组织相容性复合体II类(MHCII)四聚体检测了一种新型解毒细菌ADP核糖化肠毒素dmLT皮内免疫后的粘膜免疫反应，结果表明，我们可以通过与CD103+皮肤树突状细胞的接触来重定向内源性Th17 CD4T细胞和B细胞IgA免疫反应到肠粘膜。我们还表明，在沙门氏菌感染的小鼠模型中，用dmLT加单一的CD4T细胞表位进行皮内免疫可以显著降低细菌负荷。这些综合的结果，加上我们过去的工作，让我们假设dmLT皮内免疫可以接触CD103+树突状细胞，它刺激抗原特异性B细胞和CD4T细胞上调肠道归巢标记和粘膜转运。我们进一步假设，当它与通过不同信号通路作用的佐剂结合时，细胞和体液免疫都可以调整以适应感兴趣的粘膜病原体。我们建议：1)评估dmLT皮内免疫与Th1或Th2驱动佐剂联合时的抗原摄取和递呈，确定这种免疫如何将2)T细胞和3)B细胞导向粘膜组织，以及4)确定这种免疫是否对沙门氏菌致死性肠道感染具有保护作用。这项研究应该为佐剂如何调节粘膜免疫提供新的见解，并使我们能够指导有利于病原体消除的反应。

 DESCRIPTION (provided by applicant): Most pathogens enter the body at mucosal surfaces, yet, to date, the majority of licensed vaccines are injected parenterally, predominantly intramuscularly. While excellent at eliciting systemic immunity, they do not always induce the required mucosal immune responses. This highlights a gap in our understanding of how immunization may be manipulated to elicit mucosal immune responses and how such knowledge might be exploited to create better vaccines for mucosal pathogens. Defining the role that adjuvants play in this response is key to developing such vaccines; however, the mechanisms that dictate adjuvant driven mucosal antibody and cellular immune responses are not well understood. Our preliminary experiments using major histocompatibility complex class II (MHCII) tetramers to examine mucosal immune responses after intradermal immunization with a novel detoxified bacterial ADP- ribosylating enterotoxin, called dmLT, demonstrate that we can retarget the endogenous Th17 CD4 T cells and B cell IgA immune responses to the intestinal mucosa possibly by engagement of CD103+ skin dendritic cells. We also show intradermal immunization with dmLT plus a single CD4 T cell epitope can significantly reduce bacterial burden in a mouse model of Salmonella infection. These combined results, in addition to our past work, lead us to hypothesize that intradermal immunization with dmLT engages CD103+ dendritic cells, which prime antigen-specific B cells and CD4 T cells to upregulate gut- homing markers and mucosal trafficking. We further posit that when this is combined with adjuvants acting via different signaling pathways, both cellular and humoral immunity can be tuned to adapt to a mucosal pathogen of interest. We propose to: 1) assess antigen uptake and presentation when intradermal immunization with dmLT is combined with Th1 or Th2 driving adjuvants, determine how this immunization directs 2) T cells and 3) B cells to mucosal tissue, and 4) determine if this immunization is protective against a lethal enteric infection with Salmonella bacteria. This investigation should provide novel insights into how adjuvants regulate immunity at the mucosa and allow us to guide the response in favor of pathogen elimination.