The NLR-inflammasome as mediator of Alum's adjuvanticity

描述（由申请人提供）：明矾是唯一被批准用于人类疫苗常规接种的佐剂，尽管其佐剂性的基础仍然知之甚少。我们最近已经证明明矾激活caspase-1并诱导成熟的白介素-12 （IL-12）和IL-18的分泌。我们的初步结果还表明，Alum的caspase-1激活和IL-12分泌的刺激依赖于ASC蛋白，ASC蛋白是几种nod样受体（NLR）使用的一种衔接分子，这表明该家族的成员可能介导Alum的免疫刺激作用。NLR是一种模式识别受体，可识别位于细胞质中的微生物产物。一些NLR是炎性小体的多蛋白复合体的一部分，该复合体还包含适配器ASC和caspase-1， caspase-1是加工和分泌IL-12和IL-18所需的蛋白酶。大量研究证明了IL-12和IL-18的辅助活性，特别是它们促进Th2分化的能力。众所周知，明矾是Th1反应的较差诱导剂，但它能成功地维持Th2反应，这表明明矾的辅助作用可能与其诱导IL-12和IL-18分泌的能力有关。以前已经分析过IL-12和IL-18在明矾佐剂性中的作用，但结果相互矛盾或不确定。鉴于我们最近的结果，有必要重新审查这个问题。本拨款提案将在分子水平上阐明明矾的作用机制，具体目标如下：1。验证NLR家族成员介导明矾caspase-1激活和IL-12/IL-18分泌的假设：1。验证caspase-1的激活和IL-12/IL-18的释放介导明矾佐剂活性的假说。疫苗接种仍然是工业化国家和发展中国家抗击传染病的最有希望的战略。明矾是唯一被批准用于常规人类疫苗接种的佐剂，尽管其免疫刺激活性的基础仍然知之甚少。本拨款提案中所述的研究将增加我们对明矾作用机制的理解。更深入地了解决定佐剂免疫刺激特性的机制是合理设计更复杂疫苗的先决条件。

DESCRIPTION (provided by applicant): Alum is the only adjuvant approved for routine use in human vaccination although the basis for its adjuvanticity remains poorly understood. We have recently demonstrated that Alum activates caspase-1 and induces secretion of mature Interleukin-12 (IL-12) and IL-18. Our preliminary results also show that caspase-1 activation and stimulation of IL-12 secretion by Alum is dependent on the protein ASC, an adaptor molecule used by several Nod-Like receptors (NLR), suggesting that members of this family may mediate Alum's immunostimulatory effects. NLR are pattern recognition receptors that recognize microbial products situated in the cytoplasm. Several NLR are part of a multiproteins complex called inflammasome that also contains the adaptor ASC and caspase-1, the protease required for processing and secretion of IL-12 and IL-18. Numerous studies documented the adjuvant activities of IL-12 and IL-18 and in particular their ability to encourage Th2 differentiation. Alum is notoriously a poor inducer of Th1 responses while it successfully sustains Th2 responses suggesting that Alum's adjuvanticity may be related to its ability to induce IL-12 and IL-18 secretion. The involvement of IL-12 and IL-18 in Alum adjuvanticity has been previously analyzed but with contradictory or inconclusive results. In light of our recent results a re-examination of this issue is needed. The present grant proposal will elucidate at the molecular level the mechanism of action of Alum by addressing the following specific aims: 1. Test the hypothesis that members of the NLR family mediate caspase-1 activation and IL-12/IL-18 secretion by Alum: 2. Test the hypothesis that caspase-1 activation and release of IL-12/IL-18 mediate the adjuvant activity of Alum. Vaccination remains the most promising strategy to fight infectious diseases in both industrialized and developing countries. Alum is the only adjuvant approved for routine use in human vaccination although the basis for its immunostimulatory activity remains poorly understood. The studies described in this grant proposal will increase our understanding of the mechanism of action of Alum. A deeper understanding of the mechanisms that determine the immunostimulatory properties of adjuvants is a prerequisite for the rational design of more sophisticated vaccines.