HIV sexual transmission in mice:study of microbicide efficacy

描述(申请人提供)：本申请是根据RFA-AI-07-034提交的。我们构建了一种由嵌合HIV-1，EcoHIV系统感染免疫活性小鼠的模型。我们以前的研究表明，EcoHIV在感染的小鼠的淋巴细胞和巨噬细胞中复制，小鼠的感染对抗逆转录病毒药物敏感，生产性感染持续数月诱导免疫反应，HIV-1 DNA疫苗可以阻断小鼠的感染。这里报道的初步结果表明，EcoHIV在小鼠中的性传播是快速和有效的。我们在这项应用中的总体目标是开发小鼠感染系统来研究性传播HIV-1的机制，作为测试候选杀微生物剂效果的平台。其具体目的是：1)优化EcoHIV在小鼠性传播的条件，并对干预措施进行评价。2)明确EcoHIV经性传播的细胞类型。3)检测抗逆转录病毒类杀菌剂对EcoHIV性传播的抑制作用。4)确定性传播对HIV-1亚型的依赖性，以及以抗逆转录病毒为基础的杀菌剂对不同HIV-1亚型的疗效。5)确定联合使用HIV-1 DNA疫苗和杀微生物剂是否可以防止B亚型EcoHIV的性传播。嵌合的HIV-1将通过与通过接种感染的雄性小鼠交配而传播给传统的、具有免疫能力的雌性小鼠。实时聚合酶链式反应将测量多个器官中的病毒载量，并通过流式细胞仪和共聚焦显微镜鉴定有生产力的感染细胞。目标1-3的实现将为在与当前艾滋病毒-1流行病直接相关的研究中将模型扩展到目标4-5以及控制艾滋病毒-1流行病的现实手段提供坚实的基础和理由。艾滋病毒-1感染继续在世界范围内传播，主要是通过性传播。公共卫生界通过研究杀微生物剂来应对这一大流行，妇女可以使用这种化合物来防止艾滋病毒-1在性交期间的传播。不幸的是，在妇女开始使用之前，没有简单的方法来确定正在开发的许多杀微生物剂中哪一种真正阻止了艾滋病毒-1的传播。在临床试验中，一些最先由女性检测的药物实际上增加了艾滋病毒-1的传播。这项应用旨在开发一种系统，用于在小鼠身上进行杀微生物剂的临床前测试，以确定它们减少或防止HIV-1性传播的能力。我们已经证明，我们通过基因工程设计的一种HIV-1感染小鼠在交配过程中非常容易传播。我们建议优化这一系统，以确定杀菌剂阻止HIV-1性传播的程度。我们还将在小鼠身上测试今天广泛分布的HIV-1形式如何被杀菌剂控制。我们已经证明，接种疫苗可以降低小鼠对HIV-1的易感性。我们还计划给小鼠接种疫苗，然后用杀菌剂进行治疗，以确定是否有可能完全防止病毒的性传播。我们希望，HIV-1在小鼠体内的性传播模型可以加速开发安全有效的杀微生物剂，可用于控制艾滋病的流行。

DESCRIPTION (provided by applicant): This application is submitted in response to RFA-AI-07-034. We have constructed a model of systemic infection of immunocompetent mice by chimeric HIV-1, EcoHIV. Our previous studies indicate that EcoHIV replicates in lymphocytes and macrophages in infected mice, infection in mice is sensitive to antiretroviral drugs, productive infection persists for months inducing immune responses, and HIV-1 DNA vaccination can block infection in mice. Preliminary results reported here show that sexual transmission of EcoHIV in mice is rapid and efficient. Our overall goal in this application is to develop the mouse infection system to investigate the mechanisms of sexual transmission of HIV-1 as a platform to test efficacy of candidate microbicides. The Specific Aims of are: 1) to optimize conditions for sexual transmission of EcoHIV in mice and evaluation of interventions. 2) to identify the cell types involved in sexual transmission of EcoHIV. 3) to test the inhibition of sexual transmission of EcoHIV by antiretroviral-based microbicides. 4) to determine the HIV-1 subtype dependence of sexual transmission and efficacy of antiretroviral based microbicides against different HIV-1 subtypes. 5) to determine whether combination administration of an HIV-1 DNA vaccine followed by a microbicide can prevent sexual transmission of subtype B EcoHIV. Chimeric HIV-1 will be transmitted to conventional, immunocompetent female mice by mating with males infected through inoculation. Virus burden in multiple organs will be measured by real- time PCR and productively infected cells will be identified by flow cytometry and confocal microscopy. Accomplishment of Aims 1-3 will provide a firm foundation for and justification to extend the model to Aims 4-5 in studies directly relevant to the current HIV-1 epidemic and realistic means to control it. HIV-1 infection continues to spread worldwide, primarily by sexual transmission. The public health community responded to this pandemic by research into microbicides, compounds that women can apply to prevent transmission of HIV-1 during intercourse. Unfortunately, there is no simple way to determine which of many microbicides being developed actually blocks HIV-1 transmission before women begin their use. Some of the first to be tested by women in clinical trial actually increased HIV-1 transmission. This application is designed to develop a system for preclinical testing of microbicides in mice to determine their ability to reduce or prevent sexual transmission of HIV-1. We have shown that a form of HIV-1 that we genetically engineered to infect mice is very easily transmitted during mating. We propose to optimize this system to determine how well microbicides block sexual transmission of HIV-1. We shall also test in mice how the forms of HIV-1 that are widely distributed today can be controlled by microbicides. We have already shown that vaccination can reduce susceptibility to HIV-1 in mice. We also plan to both vaccinate mice and then treat with microbicides to determine if it is possible to completely prevent sexual transmission of the virus. Our hope is that the model of sexual transmission of HIV-1 in mice can accelerate the development of safe and effective microbicides that can be used to control the AIDS pandemic.