Novel peptide antagonist theraphy for superantigen- induced lethal shock

细菌超抗原(SAG)是一种外毒素，可以触发过度的免疫反应，从而可能导致 致命的电击。因为它们能够在极低的浓度下诱导丧失行为能力，并引发 震荡、易于生产和异常稳定的凹陷被归类为B类生物 武器。试图通过阻断下游效应器来逆转SAG中毒的有害影响 如肿瘤坏死因子-α，由于诱导的大量水平而失败。我们制备了多肽模拟物 SAG中的接触结构域和一种新的SAG受体，该受体是诱导Th1细胞因子所必需的 在D-氨基半乳糖(D-GalN)致敏的SEB小鼠模型中预防致死性休克 猪的丧失行为能力。由于SAG与革兰氏阴性细菌内毒素(LPS)共暴露可能更多 在临床上，这项建议将检验拮抗剂多肽可以预防SAG/LPS的假设 杀伤力强，拯救暴露的动物，同时保持适应性免疫反应。具体而言 目的确定拮抗肽是否能保护和拯救小鼠免受内毒素/SAG的致死协同作用。 暴露于SAG和肠源性内毒素可能模拟了SAG的临床情况和SAG诱导的机制 病理不同于D-Gain敏化所发生的。在第二个具体目标中，我们将定义 拮抗肽介导的保护机制，表明它对SAGS具有广谱的保护作用，并且 评估肽拮抗剂是否削弱了对抗原或宿主防御的免疫刺激的反应 防止活体感染。从SAG攻击小鼠血清中提纯多肽免疫球蛋白 拮抗剂将通过与SAG不同结构域的多肽进行酶联免疫吸附试验进行检测。这些研究将是 随后进行交叉抑制ELISA研究，以确定SAG保守表位的特异性免疫球蛋白水平。自.以来 最近的研究表明，SAGS可能会改变APC功能，在特定的目标III中，我们将分析 多肽拮抗剂(1)抑制SAG对人单核细胞的作用，特别是Toll样受体的表达 和细胞因子诱导或(2)削弱人树突状细胞呈递炭疽杆菌抗原给T细胞的能力 淋巴细胞。这些研究将进一步确定SAG信号转导的新机制，以及SAG信号转导的有效性和 一种针对多发性下垂的新型治疗干预措施的安全性。如果我们成功了，这些肽 模仿学可能很快就会准备好进行第一阶段的测试。

Bacterial superantigens (SAg) are exotoxins that trigger an excessive immune response that may lead to lethal shock. Because of their ability to induce incapacitation at exceedingly low concentrations and to elicit shock, their ease of production and their exceptional stability, SAgs are classified as Category B biological weapons. Attempts to reverse the deleterious effects of SAg intoxication by blocking downstream effectors such as TNF-a have failed owing to the massive levels induced. We prepared peptide mimetics of the contact domains in the SAg and a novel SAg receptor essential for the induction of Th1 cytokines which prevent lethal shock in a D-galactosamine (D-GalN)-sensitized mouse model of SEB as well as incapacitation in pigs. Since co-exposure of SAg with Gram-negative bacterial endotoxin (LPS) may be more clinically relevant, this proposal will test the hypothesis that antagonist peptides can prevent SAg/LPS svnergistic lethality and rescue exposed animals, while preserving adaptive immune responses. In Specific Aim I we will determine whether antagonist peptides protect and rescue mice from LPS/SAg lethal synergy. Exposure to SAg and gut-derived LPS likely mimics the clinical situation, and the mechanism of SAg-induced pathology differs from that which occurs with D-GaIN sensitization. In Specific Aim II, we will define the mechanism of antagonist peptide-mediated protection, show that it is broad-spectrum against SAgs, and assess whether peptide antagonists impair responses to immune stimulation with antigens or host defenses against live infection. IgG purified from the serum of mice challenged with SAg in the presence of peptide antagonist will be.tested by ELISA against peptides from different domains of SAg. These studies will be followed by cross-inhibition ELISA studies to identify IgG levels specific for SAg conserved epitopes. Since recent studies suggest that SAgs may alter APC function, in Specific Aim III we will analyze whether peptide antagonists (1) inhibit SAg effects on human monocytes, particularly Toll-like receptor expression and cytokine induction or (2) impair the ability of human dendritic cells to present B. anthracis antigens to T lymphocytes. These studies will further define a new mechanism of SAg signaling and the efficacy and safety of a novel therapeutic intervention against multiple SAgs. If we are successful, these peptide mimetics could soon be ready for phase I testing.