Polyomavirus Infection after Kidney Transplantation

描述（由申请人提供）：肾移植物的BK病毒感染已成为一个相当令人关注的问题。我们在确定这些患者的临床过程中发挥了主导作用。在过去的3年里，我们在这一领域的努力一直由NIH赞助的RO-1赠款资助。我们现在准备了一份竞争性的继续资助申请，以继续我们对这一重要问题的研究。具体目标1：描述BKV的序列多样性和系统进化，并确定其在临床实践中对分子诊断检测的潜在影响。我们假设变异BKV毒株正在损害我们（a）确定病毒感染的真实患病率和（B）准确定量从个体患者获得的临床样本中的病毒基因组载量的能力。我们的目标将是澄清新病毒株在自然界中发展的速度，并确定基于PCR的诊断检测是否也需要不断调整以补偿这种持续的进化。具体目标#2：描述影响PV在肾脏中复制的宿主和病毒因素。我们建议在细胞培养系统中直接测量突变型和野生型病毒的病毒复制率。此外，我们将确定BK病毒尿和病毒血症的风险是否取决于能够调节宿主-病原体相互作用的基因的供体或宿主多态性。具体目标#3：检查阴燃BKV感染对慢性移植物肾病发展的影响。我们假设，约35%的患者出现无症状病毒尿，这是一种郁积性BKV感染，可导致慢性移植肾肾病的发生。为了解决这个问题，我们将使用存档的活检材料来评估病毒感染患者肾功能不全的连续进展。具体目标4：利用三维同源模建和虚拟筛选技术，寻找能够结合VP-1和T抗原分子功能域的抗BKV药物。鉴于BKV感染在肾移植受者中的日益重要性，迫切需要开发适合临床使用的抗BKV药物。我们假设，抗BKV药物可以通过筛选化合物库来发现，这些化合物可以结合两种关键的病毒蛋白，即病毒衣壳蛋白-1（VP-1）和大T抗原。

DESCRIPTION (provided by applicant): BK virus infection of the renal allograft has become a matter of considerable concern. We have played a leading role in defining the clinical course of these patients. Our effort in this area has been funded by an NIH sponsored RO-1 grant for the past 3 years. We have now prepared a competing continuation grant application to continue our study of this important problem. Specific Aim # 1: To characterize the sequence diversity and phylogenetic evolution of BKV, and determine its potential impact on molecular diagnostic assays in clinical practice. We hypothesize that variant BKV strains are compromising our ability to (a) determine the true prevalence of viral infection, and (b) accurately quantitate the viral genomic load in clinical samples obtained from individual patients. It will be our goal to clarify the rate at which new viral strains are developing in nature, and to determine whether PCR-based diagnostic assays will also need to be continuously adapted to compensate for this continuing evolution. Specific Aim # 2: To delineate host and viral factors that affect PV replication in the kidney. We propose to directly measure viral replication rates in mutant and wild type viruses in a cell culture system. In addition, we will determine if the risk of developing BK viruria and viremia is dependent on donor or host polymorphisms in genes capable of modulating host- pathogen interactions. Specific Aim #3: To examine the impact of smoldering BKV infections on the development of chronic allograft nephropathy. We hypothesize that asymptomatic viruria, which occurs in approximately 35% of our patients, represents a smoldering BKV infection that contributes to the development of chronic allograft nephropathy. To address this issue, we will use archival biopsy material to assess the serial progression of renal dysfunction in virus infected patients. Specific Aim # 4: To use 3- dimensional homology modeling and virtual screening technology to discover anti-BKV drugs capable of binding functional domains on the VP-1 and T-antigen molecules. Given the growing importance of BKV infection in renal transplant recipients, there is a pressing need to develop anti-BKV drugs suitable for clinical use. We hypothesize that anti-BKV drugs can be discovered by screening chemical libraries for compounds that can bind to two key viral proteins, namely, viral capsid protein-1 (VP-1) and large T antigen.