Cardiotoxicity of Streptococcal Pyrogenic Exotoxins

描述(由申请人提供)：长期目标是确定超抗原(SAG)引起疾病的特征。情绪低落会导致中毒性休克综合征(TSS)。然而，我们的假设是，情绪低落会导致其他疾病。我们推测，新出现的耐甲氧西林金黄色葡萄球菌(MRSA)菌株(美国200、300和400)产生的下垂会导致坏死性肺炎(NP)、肺TSS和心内膜炎。我们还假设，当毒性消除时，SAGS可能有辅助作用。我们计划实现两个具体目标： 目的1：表征非致命性SAG类毒素的佐剂活性，这些类毒素在静脉或粘膜给药时，由于其与CD40的相互作用而放大抗体的产生。我们提供的证据表明，SAGS包含一个促进粘膜穿透的区域，该区域独立于超抗原性，并放大免疫反应；这两种活性都源于与免疫共刺激分子CD40的相互作用。 具体目标1a。目的：制备缺乏CD40结合的SAGS、TSS毒素-1和链球菌热原外毒素C的十二肽结构域突变体。 具体目标1b。检测野生型SAGS和非致死性突变体在免疫印迹和Biaccore分析中结合CD40的能力。 具体目标1c。测试野生型凹陷和十二肽突变体对猪和兔阴道粘膜的穿透能力。 具体目标1D。测试保持粘膜穿透和CD40结合的非致命性SAG突变体的佐剂作用，假设这两种活性都是由于突变体SAG与上皮细胞和APC上的CD40相互作用所致。 目的：阐明葡萄球菌下垂在新发MRSA引起的NP、肺TSS和心内膜炎中的作用。我们假设MRSA菌株比MSSA菌株产生更高水平的SAG，并且与MSSA相比，MRSA中控制SAG产生的调控DNA发生了改变。我们还假设，MRSA菌株产生NP、肺TSS和心内膜炎所需的高水平sAG，α-溶血素和潘通-瓦伦丁杀白素导致感染，但两者都不是必需的，sAG通过延迟抗体反应而导致感染。这些将通过使用同基因菌株、通过接种疫苗和监测宿主反应来进行测试。 具体目标2a。新出现的耐甲氧西林金黄色葡萄球菌的体外特性。 具体目标2b。SAG在CA-MRSA肺部感染中的体内作用特征。 具体目标2c。SAG对耐甲氧西林金黄色葡萄球菌心内膜炎的贡献特征。

DESCRIPTION (provided by applicant): The long-term goals are characterization of superantigens (SAgs) causation of diseases. SAgs cause toxic shock syndrome (TSS). However, it is our hypothesis that SAgs contribute to other illnesses. We theorize SAgs produced by emerging strains of methicillin resistant Staphylococcus aureus (MRSA) (USA 200, 300, and 400) contribute to necrotizing pneumonia (NP), pulmonary TSS, and endocarditis. We also hypothesize there may be adjuvant uses for SAgs, when toxicity is eliminated. We plan two specific aims: Aim 1: To characterize adjuvant activities of non-lethal SAg toxoids that amplify antibody production when administered intravenously or mucosally, as a consequence of their abilities to interact with CD40. We provide evidence that SAgs contain a domain that facilitates mucosal penetration, independent of superantigenicity, and that amplifies immune responses; both activities result from interaction with the immune co-stimulatory molecule CD40. Specific aim 1a. To prepare mutants in the dodecapeptide domain of SAgs, TSS toxin-1 and streptococcal pyrogenic exotoxin C, that lack CD40 binding. Specific aim 1b. To test wild-type SAgs and non-lethal mutants for ability to bind CD40 in immunoblots and Biacore analysis. Specific aim 1c. To test wild-type SAgs and dodecapeptide mutants for ability to penetrate porcine and rabbit vaginal mucosa. Specific aim 1d. To test non-lethal SAg mutants that retain mucosal penetration and CD40 binding for adjuvanticity, with the hypothesis that both activities result from mutant SAg interaction with CD40 on epithelial cells and APCs. Aim 2: To elucidate the contribution of staphylococcal SAgs to NP, pulmonary TSS, and endocarditis caused by emerging MRSA. We hypothesize that MRSA strains make higher levels of SAgs than MSSA strains, and that regulatory DNA controlling SAg production in MRSA is altered compared to MSSA. We also hypothesize that MRSA strains make high levels of SAgs required for NP, pulmonary TSS, and endocarditis, that alpha- hemolysin and Panton-Valentine leukocidin contribute to infections, but neither is required, and that SAgs contribute to infections by delaying antibody responses. These will be tested by use of isogenic strains, through vaccination, and by monitoring host responses. Specific aim 2a. In vitro characterization of emerging MRSA strains. Specific aim 2b. In vivo characterization of SAg contribution to CA-MRSA pulmonary infections. Specific aim 2c. Characterization of SAg contribution to MRSA endocarditis.