Soluble high-affinity T cell receptors prevent MRSA lethality

描述(申请人提供)：耐甲氧西林金黄色葡萄球菌(MRSA)和甲氧西林敏感金黄色葡萄球菌(MSSA)是严重威胁人类健康的疾病，导致一系列疾病。最近，疾控中心和他的同事报告说，MRSA是美国严重感染和传染病死亡的最重要原因。MRSA和MSSA致死的一个主要因素是被称为超级抗原的分泌性毒素。几十年来，随着美国军方根据1969年终止的旧生物武器计划储存了大量葡萄球菌肠毒素B(SEB)，与这些超级抗原相关的致命性已经得到了认可。这些毒素的作用机制是众所周知的-它们通过与T细胞上的T细胞受体结合并刺激大量炎性细胞因子的释放而在细胞外发挥作用。我们已经设计了可溶性T细胞受体，与超级抗原高亲和力结合，以防止毒素相关的致死。这项建议的目的是建立在第一阶段工作成功的基础上，在第一阶段，用新型治疗性(可溶的、高亲和力的T细胞受体，称为IMV-01)治疗能够中和肺内兔模型中MRSA分泌的SEB。第二阶段工作的假设是，可以提高治疗药物的产量，IMV-01和已经针对其他临床重要超级抗原(SEC和TSST-1)设计的两个可溶性T细胞受体引线(IMV-02和IMV-03)可以作为鸡尾酒中和这些毒素，并防止MRSA引起的肺炎造成的死亡。其具体目的是：1)确定优化V？-TCRs IMV-01、IMV-02和IMV-03的产量和纯度的最佳条件：2)在有或没有万古霉素的兔肺内模型中，分别确定IMV-01、IMV-02和IMV-03分别中和MRSA菌株产生的毒素的有效剂量和时间；(3)研究IMV-01、IMV-02和IMV-03作为三种不同的MRSA株，在有或无万古霉素存在的情况下，对兔肺内攻击致死的保护作用。 公共卫生相关性：耐药金黄色葡萄球菌分离株经常通过细菌在呼吸道粘膜和皮肤上的定植引发严重的人类疾病，然后分泌被称为超级抗原的强效毒素。疾病包括严重的病毒后肺炎、过敏性皮肤病和伤口愈合延迟，这些疾病每年在美国影响成千上万的人。分泌的毒素直接参与该病的影响，并可导致死亡。在这项应用中，ImmuVen将开发一种中和这些毒素的治疗方法，并检查其在由细菌引起的各种致命性肺炎模型中的有效性。

DESCRIPTION (provided by applicant): Methicillin resistant Staphylococcus aureus (MRSA) and methicillin sensitive S. aureus (MSSA) are highly significant human health threats that are responsible for a range of diseases. Recently, the CDC and colleagues reported that MRSA are the most significant causes of serious infections and infectious disease deaths in the United States. A major factor involved in the lethality of MRSA and MSSA are secreted toxins, known as super antigens. The lethality associated with these super antigens has been appreciated for decades, as the U.S. military stockpiled large amounts of staphylococcal enterotoxin B (SEB) under its old bioweapons program that was terminated in 1969. The mechanism of action of the toxins is well known - they act extracellularly by binding to the T cell receptor on T cells and stimulating massive release of inflammatory cytokines. We have engineered soluble T cell receptors for high-affinity binding to super antigens to prevent toxin-associated lethality. The objective of this proposal is to build on the success of work completed in Phase I where treatment with the novel therapeutic (soluble, high-affinity T cell receptor, called IMV-01) was able to neutralize SEB secreted from MRSA in an intrapulmonary rabbit model. The hypotheses of the Phase II work are that yields of the therapeutics can be improved, that IMV-01 and two soluble T cell receptor leads (IMV-02 and IMV-03) already engineered against the other clinically important super antigens (SEC & TSST-1) can be co-administered as a cocktail to neutralize these toxins, and prevent lethality due to pneumonia caused by MRSA. The Specific Aims are: 1) To determine the best conditions for optimizing the yield and purity of the V?-TCRs IMV-01, IMV-02 and IMV-03; 2) To determine the effective dose and timing of IMV-01, IMV-02 or IMV-03 individually to neutralize their respective toxins produced by MRSA strains in an intrapulmonary rabbit model in the presence or absence of vancomycin; and 3) To determine the efficacy of using IMV-01, IMV-02 and IMV- 03 as a cocktail to protect rabbits from death due to intrapulmonary challenge with three different MRSA strains secreting either SEB + SEC, SEB + TSST-1 or SEC + TSST-1, in the presence or absence of vancomycin. PUBLIC HEALTH RELEVANCE: Antibiotic-resistant Staphylococcus aureus isolates frequently initiate serious human diseases through the bacterium's colonization of respiratory mucosa and skin, followed by secretion of potent toxins referred to as super antigens. Illnesses include serious post viral pneumonias, allergic skin diseases, and delayed wound healing that affect thousands of individuals each year in the United States. The secreted toxins are directly involved in the effects of the, disease and can cause death. In this application, ImmuVen will develop a therapeutic that neutralizes these toxins, and examine its effectiveness in various models of lethal pneumonia caused by the bacterium.