Cardiotoxicity of Streptococcal Pyrogenic Exotoxins

描述（由申请人提供）：长期目标是表征疾病的超抗原（SAg）病因。SAG引起中毒性休克综合征（TSS）。然而，我们的假设是，SAgs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（USA 200、300和400）产生的SAG导致坏死性肺炎（NP）、肺TSS和心内膜炎。我们还假设，当毒性被消除时，SAgs可能有辅助用途。我们有两个具体目标： 目标1：表征非致死性SAg类毒素的佐剂活性，当静脉内或粘膜给药时，由于其与CD 40相互作用的能力，其放大抗体产生。我们提供的证据表明，SAGS含有一个结构域，有利于粘膜渗透，独立的超抗原性，并放大免疫反应，这两种活动的结果与免疫共刺激分子CD 40的相互作用。 具体目标1a。制备缺乏CD 40结合的SAgs、TSS毒素-1和链球菌致热外毒素C的十二肽结构域的突变体。 具体目标1b。在免疫印迹和Biacore分析中测试野生型SAg和非致死突变体结合CD 40的能力。 具体目标1c。测试野生型SAg和十二肽突变体穿透猪和兔阴道粘膜的能力。 具体目标1d。为了测试保留粘膜渗透和CD 40结合的佐剂性的非致死性SAg突变体，假设这两种活性均由突变体SAg与上皮细胞和APC上的CD 40相互作用引起。 目的2：阐明金黄色葡萄球菌SAgs对新生MRSA引起的NP、肺TSS和心内膜炎的作用。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Panton-Valentine杀白细胞素有助于感染，但两者都不是必需的，并且SAg通过延迟抗体应答而有助于感染。将通过使用等基因菌株、接种疫苗和监测宿主反应来检测这些病毒。 具体目标2a。新兴MRSA菌株的体外表征。 具体目标2b。SAg对CA-MRSA肺部感染的贡献的体内表征。 具体目标2c。SAg对MRSA心内膜炎的贡献的表征。

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.