Mycoplasma genitalium variation in longitudinally infected men

描述（由申请人提供）：生殖支原体（MG）是男性尿道炎的一种病因，其在宫颈炎、尿道炎、盆腔炎、输卵管因素不孕症和女性早产中的病因作用日益得到认可。不幸的是，这种细菌对靶向细胞壁的抗生素和目前用于治疗原发性疾病和可能的严重生殖道疾病后遗症的许多抗生素具有耐药性。MG感染可能持续数月至数年，在男性和女性中，尽管在感染期间诱导炎症反应和特异性抗体。我们和其他人假设，这种持久性是基于MG逃避宿主免疫反应的能力，通过抗原变异，其表面蛋白，MgpB和MgpC位于其复杂和独特的终端细胞器。支持这一假设，我们已经表明，在mgpB和mgpC，编码这些蛋白质的相邻基因的变化，是广泛的在体内和随着时间的推移在宫颈/阴道感染。然而，到目前为止，我们还无法通过评估感染诱导的抗体对当代和时间匹配的患者分离株的基因变异和抗原选择的作用来检验这一假设。我们最近的NIH资助的M。生殖器给了我们这样的机会。在这个完整的试验中，M。确定生殖器感染的男性，并要求他们每隔三周返回进行三到四次访问，在此期间收集血清，并检测他们的M.生殖器菌株 培养并鉴定。这些实验是前所未有的，因为巡回研究将使用最近的临床分离株，而不是实验室适应菌株。因此，我们建议：1）在整个纵向研究中表征不同时间点mgpB序列变异的演变，2）将mgpB中特定可变序列的清除与感染男性中针对这些序列的抗体的产生相关联，以及3）确定针对这些变异序列的抗体是否增强补体介导的M的杀伤。生殖器这项研究是创新的，在其经济的使用一个非常有价值的和良好的特点的患者标本集，以评估这种新认识的病原体的持久性基因变异的作用。这项研究的意义在于它将部分揭示这种新认识的生殖器病原体的免疫逃避机制。我们关注这种未充分研究的细菌的免疫发病机制的潜在影响是巨大的，因为可以确定新的干预和治疗靶点。

DESCRIPTION (provided by applicant): Mycoplasma genitalium (MG) is a cause of urethritis in men and is becoming increasingly recognized for its etiologic role in cervicitis, endometritis, pelvic inflammatory disease, tubal factor infertility, and preterm birth in women. Unfortunately, this bacterium is resistant to cell wall-targeting antibiotics and to many of the antibiotics curretly used to treat primary disease and possible serious reproductive tract disease sequelae. MG infection may persist in humans for months to years in both men and women despite the induction of an inflammatory response and specific antibodies during infection. We and others have hypothesized that this persistence is based on the ability of MG to evade the host immune response by antigenic variation in two of its surface proteins, MgpB and MgpC located in its complex and unique terminal organelle. Supporting this hypothesis, we have shown that variation in mgpB and mgpC, the adjacent genes encoding these proteins, is extensive both in vivo and evolves over time in cervical/vaginal infections. However, up to this point, we have not been able to test this hypothesis by assessing the role of antibodies induced by infection on gene variation and antigenic selection of contemporary and temporally matched patient isolates. Our recent NIH-funded treatment trial for M. genitalium has given us such an opportunity. In this completed trial, M. genitalium infected men were identified and asked to return at three week intervals for three to four visits at which time sera was collected and their M. genitalium strains were cultured and characterized. These experiments are unprecedented because recent clinical isolates, not laboratory-adapted strains will be used in tour study. Thus we propose to 1) characterize the evolution of mgpB sequence variation of at different time points throughout the longitudinal study, 2) correlate the clearance of specific variable sequences in mgpB with the development of antibodies to these sequences in the infected men, and 3) determine if the antibodies to these variant sequences enhance complement-mediated killing of M. genitalium. This study is innovative in its economical use of an extremely valuable and well-characterized set of patient specimens to assess the role of gene variation on persistence of this newly recognized pathogen. This study is significant in that it will reveal, in part, the mechanisms of immune evasion in this newly recognized genital pathogen. The potential impact of our focus on the immunopathogenesis of this understudied bacterium is great in that novel targets for intervention and treatment may be identified.