TRANSMISSION AND VIRAL DYMANICS OF DRUG RESISTANT HIV-1

本提案的总体目标是定义和理解控制多药耐药HIV-1的传播、适应性和体内复制动力学的病毒学决定因素。对所有三种可用药物类别的单个药物产生耐药性的途径已经得到了很好的表征。耐药的分子基础发生在逆转录水平，当突变发生时，在改变的蛋白质（如蛋白酶和逆转录酶）中以氨基酸取代的形式表达。最终，这导致HIV-1变异在抗病毒药物的强选择压力下表现出生存优势。随着这些HIV-1变异体的进化，并在接受治疗的人群中变得更加普遍，确定这些病毒是否正在传播，如果传播，传播频率是多少，变得至关重要。为了解决这一问题，将通过对新感染个体的病毒进行表型和基因型分析来确定耐药HIV-1传播的流行程度。这具有相当大的公共卫生重要性，因为耐药病毒的传播将导致治疗做法的改变，并将证明预先测试病毒对现有药物的敏感性是合理的。了解与传播有关的病毒适应性和复制能力的决定因素也至关重要。据推测，通过产生耐药性，病毒在适应性和复制能力方面获得了“障碍”。然而，目前尚不清楚这是否会影响传播性。为了确定耐药突变对病毒传播的影响，我们将构建耐药重组病毒，并利用多种细胞靶标在体外模拟病毒传播发生的粘膜表面环境，对其复制动力学进行表征。最后，为了进一步了解多重耐药病毒的病毒动力学，将在个体中进行体内介入研究，以推断耐药病毒在体内复制的参数。

The overall goal of this proposal is to define and understand the virologic determinants which govern the transmission, fitness, and in vivo replication dynamics of multi-drug resistant HIV-1. The pathway to resistance to individual agents from all three available drug classes has been well characterized. The molecular basis of drug resistance occurs at the level of reverse transcription, when mutations occur and are expressed as amino acid substitutions in altered proteins, such as protease and reverse transcriptase. Ultimately this results in an HIV-1 variant exhibiting a survival advantage in the presence of the strong selective pressure of antiviral agents. As these HIV-1 variants evolve and become more prevalent in the treated community, it becomes critical to determine whether these viruses are being transmitted, and if so in what frequency? To address this issue, the prevalence of resistant HIV-1 transmission will be determined using phenotypic and genotypic analysis of viruses from newly infected individuals. This is of considerable public health importance as the transmission of drug resistant viruses will result in changes in therapeutic practices and will justify pretreatment testing for virus susceptibility to available drugs. It is also critical to understand the determinants of virus fitness and replicative capacity as it relates to transmission. It is hypothesized that by becoming resistant the virus acquires a "handicap" in fitness and replicative capacity. However, it remains unknown whether this affects transmissibility. To determine the effects of resistance-conferring mutations on transmissibility, resistant recombinant viruses will be constructed and their replication kinetics characterized in vitro using a variety of cellular targets which simulate the environment of the mucosal surface at which transmission occurs. Finally, to further understand the viral dynamics of multi-drug resistant viruses, in vivo interventional studies will be performed in individuals to deduce parameters of drug resistant virus replication in vivo.