The NLR-inflammasome as mediator of Alum's adjuvanticity

描述（由申请方提供）：明矾是唯一获批用于人类疫苗接种常规用途的佐剂，但其佐剂性的基础仍知之甚少。我们最近已经证明，明矾激活caspase-1，并诱导分泌成熟的白细胞介素-12（IL-12）和IL-18。我们的初步研究结果还表明，半胱天冬酶-1激活和刺激IL-12分泌的明矾是依赖于蛋白ASC，衔接分子使用的几个节点样受体（NLR），这表明该家庭的成员可能介导明矾的免疫刺激作用。NLR是识别位于细胞质中的微生物产物的模式识别受体。几种NLR是称为炎性体的多蛋白复合物的一部分，该复合物还包含衔接子ASC和半胱天冬酶-1，该蛋白酶是加工和分泌IL-12和IL-18所需的蛋白酶。许多研究记录了IL-12和IL-18的佐剂活性，特别是它们促进Th 2分化的能力。众所周知，明矾是Th 1应答的不良诱导剂，而它成功地维持Th 2应答，这表明明矾的佐剂性可能与其诱导IL-12和IL-18分泌的能力有关。IL-12和IL-18在明矾佐剂性中的参与先前已被分析，但具有矛盾或不确定的结果。根据我们最近的结果，有必要重新审查这个问题。目前的拨款建议将阐明在分子水平上的明矾的行动机制，通过解决以下具体目标：1。验证NLR家族成员介导明矾激活半胱天冬酶-1和IL-12/IL-18分泌的假设：2。检验半胱天冬酶-1激活和IL-12/IL-18释放介导明矾佐剂活性的假设。 在工业化国家和发展中国家，接种疫苗仍然是防治传染病最有希望的战略。明矾是唯一被批准用于人类疫苗常规使用的佐剂，尽管其免疫刺激活性的基础仍然知之甚少。本拨款申请中描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.