HIV sexual transmission in mice:study of microbicide efficacy

描述（由申请人提供）：本申请是根据RFA-AI-07-034提交的。我们建立了嵌合型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在感染小鼠的淋巴细胞和巨噬细胞中复制，小鼠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应答，HIV-1 DNA疫苗可以阻断小鼠感染。初步结果表明，EcoHIV在小鼠中的性传播是快速和有效的。本申请的总体目标是开发小鼠感染系统，以研究HIV-1的性传播机制，作为测试候选杀微生物剂功效的平台。具体目的是：1）优化EcoHIV在小鼠中的性传播条件和评估干预措施。2)以确定参与EcoHIV性传播的细胞类型。3)测试抗逆转录病毒杀菌剂对EcoHIV性传播的抑制作用。4)确定性传播对HIV-1亚型的依赖性以及抗逆转录病毒杀菌剂对不同HIV-1亚型的有效性。5)确定HIV-1 DNA疫苗和杀微生物剂联合使用是否能预防B亚型EcoHIV的性传播。嵌合HIV-1将通过与通过接种感染的雄性小鼠交配而传播给常规的免疫活性雌性小鼠。将通过真实的时间PCR测量多个器官中的病毒负荷，并通过流式细胞术和共聚焦显微镜鉴定生产性感染的细胞。目标1-3的实现将为在与当前HIV-1流行病和控制它的现实手段直接相关的研究中将该模式扩展到目标4-5提供坚实的基础和理由。HIV-1感染继续在全世界传播，主要是通过性传播。公共卫生界对这一流行病的反应是研究杀微生物剂，妇女可以使用这种化合物来防止性交时传播HIV-1。不幸的是，在妇女开始使用杀微生物剂之前，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确实能阻止HIV-1的传播。一些最先在临床试验中由妇女测试的药物实际上增加了HIV-1的传播。该应用程序旨在开发一种用于在小鼠中进行杀微生物剂临床前测试的系统，以确定其减少或预防HIV-1性传播的能力。我们已经证明，我们通过基因工程感染小鼠的一种HIV-1病毒很容易在交配过程中传播。我们建议优化这个系统，以确定杀微生物剂如何阻断HIV-1的性传播。我们还将在小鼠中测试杀微生物剂如何控制当今广泛分布的HIV-1形式。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，然后用杀微生物剂处理，以确定是否有可能完全预防病毒的性传播。我们的希望是，小鼠中HIV-1性传播的模型可以加速开发可用于控制艾滋病流行的安全有效的杀微生物剂。

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.