IMMUNOPATHIC MYOSITIS INDUCED BY PERSISTENT VIRUS

先前的肠道病毒感染与某些人类自身免疫性疾病的发病机制有关，包括特发性炎症性肌病、青少年糖尿病、心肌病以及非炎症性疾病，如慢性疲劳综合征。肠道病毒感染的因素如何与病毒后疾病的发展相关联尚不清楚，但这一过程可能是由病毒和宿主基因组固有的因素驱动的，也可能是由这些因素与其他环境刺激的相互作用驱动的。本研究的重点是在一种具有良好特征的慢性炎症性肌病（CIM）小鼠模型中鉴定对疾病诱导至关重要的特定病毒基因或基因。新生儿感染柯萨奇病毒B1 （CVB1）可诱导易感小鼠株发生CIM。已经产生了一组CVB1变异，它们在CIM诱导方面是肌病（MP）或肌病（AMP），将用于鉴定介导CIM发展的病毒成分。首先，将产生来自原型MP和AMP变体的感染性cDNA克隆。将在体内测试克隆病毒的致病表型，以确认它们与亲本病毒相同。然后将对这两个原型病毒克隆进行测序，以确定特定的基因组差异，并构建假定的肌致病性诱导区域的图谱。接下来，将通过从克隆中创建MP/AMP嵌合体并使用五种病理指标评估CIM诱导来测试这些差异的功能意义。体内相互嵌合体感染将确认哪些基因组区域与CIM发育耦合。特定基因差异的影响将在单核苷酸水平上得到验证。将检查其余变体中的肌病区域，以确定AMP原型中的肌病变化是否保守，或者是否发生了具有相同功能效果的不同突变。这也将揭示显性疾病决定因素是否已被绘制，或者是否涉及其他病毒基因。MP3是一种在没有炎症的情况下引起虚弱的独特变异，将被更广泛地研究，以回答有关引起虚弱和炎症的病毒基因的相互关系的问题。这项研究将确定哪些病毒的决定因素与宿主相互作用，沉淀慢性免疫性疾病的发展。在未来的研究中，可以发展出有针对性的、机械的假设来探索这些相互作用。

Prior enterovirus infection has been implicated in pathogenesis of certain human autoimmune diseases including the idiopathic inflammatory myopathies, juvenile-onset diabetes, and cardiomyopathy, as well as noninflammatory diseases like chronic fatigue syndrome. How the elements of enteroviral infection are linked to development of post-viral disease is unclear, but the process is probably driven by factors inherent in viral and host genomes and possibly by interaction of these factors with other environmental stimuli. This proposal is focused on identifying the specific viral gene or genes that are crucial to disease induction in a well-characterized mouse model of chronic inflammatory myopathy (CIM). CIM is induced in susceptible mouse strains by neonatal infection with coxsackievirus B1 (CVB1). A panel of CVB1 variants has been produced that are myopathic (MP) or amyopathic (AMP) with respect to CIM induction and which will be used to identify the viral components that mediate CIM development. First, infectious cDNA clones from both a prototypic MP and an AMP variant will be produced. Pathogenic phenotypes of the cloned viruses will be tested in vivo to confirm that they are equivalent to the parental viruses. The two prototypic viral clones will then be sequenced to identify specific genomic differences and construct a map of putative myopathogenicity-inducing regions. Next, the functional significance of these differences will be tested by creating MP/AMP chimeras from the clones and evaluating CIM induction using a panel of five pathologic indicators. In vivo infection with reciprocal chimeras will confirm which genomic regions are coupled to CIM development. The effect of specific genetic differences will then be verified at the single nucleotide level. Myopathic regions in the remaining variants will be examined to determine if amyopathic changes in the AMP prototype are conserved or if different mutations have occurred which have the same functional effect. This will also reveal whether the dominant disease determinants have been mapped or if additional viral genes are involved. MP3, a unique variant that induces weakness in the absence of inflammation, will be examined more extensively to answer questions regarding the interrelatedness of viral genes that induce weakness and inflammation. This study will identify which determinants of the virus interact with the host to precipitate the development of chronic immunopathic disease. Focused, mechanistic hypotheses can then be developed to explore these interactions in future studies.