Modeling the molecular evolution of SIV to HIV using humanized mice

项目概要/摘要 由HIV-1和在较小程度上由HIV-2引起的艾滋病大流行导致3500多万人死亡 这两种病毒现在都深深扎根于人类群体中。这些罪犯是如何产生的 在20世纪世纪，来自于早已存在的良性古SIV病毒株仍然是一个谜。几 已经提出假设，包括简单的人畜共患病转移，随后传播，现代人类 迁移传播一种原本孤立的乡村疾病或祖先的无意连续传代 病毒在人体内的传播导致毒性增加。一个实验系统可以测试其中的一些 直到最近还缺乏假设。随着人类化小鼠（hu-mice）的出现， 通过移植人类免疫系统，现在已经有可能解决一些关键问题， 围绕着一种存在于非人类灵长类动物中的逆转录病毒如何跨越了数千年， 物种屏障，并演变为目前的人类大流行病。在我们的实验室和其他地方工作 已经建立了新一代的人类小鼠，可以连续产生人类T细胞，B细胞， 巨噬细胞和树突状细胞从头开始，并且对HIV-1和HIV-1感染非常敏感， 2引起AIDS典型的慢性病毒血症和CD 4 T细胞丢失。因此，我们现在处于一个独特的地位， 直接评估祖先SIV毒株在人类病毒传播、致病和 在生理学相关的体内人类替代系统中的进化。我们研究的主要目的是 利用这一独特的体内模型对黑猩猩SIVcpz和白眉猴SIVsm病毒进行连续传代 病毒株，HIV-1和HIV-2的祖先，并确定遗传和表型变化 导致了HIV病毒株的出现。我们最近通过以下方法获得了有希望的初步数据： 成功地使SIVsm和SIVcpz在hu小鼠中生长和适应。第2代的序列数据 SIVsm在gp 41中显示出固定的突变，第1代SIVcpz显示出序列变化，表明 病毒的进化。这些新出现的数据表明，我们提出的研究是可行的， 这是一个令人兴奋的目标，即了解两种艾滋病毒类型出现的遗传基础，从而揭示 一个长期的谜团 在本工作中，我们将SIVcpz和SIVsm在hu小鼠体内连续传代，以获得人适应病毒 可能分别代表HIV-1和HIV-2的完全进化株， 致病属性，推导序列数据，以确定适应性序列变化，并评估关键的 克服人类限制因素如tetherin的基因组变化。 为了进行这些有希望的研究，我们组建了一个有成就和热情的合作者团队 Drs.普雷斯顿马克思（杜兰大学）、谢尔比奥康纳和大卫埃文斯（威斯康星州大学）、弗朗索瓦维林格 (New伊比利亚研究所，路易斯安那州），布兰登基尔（NCI，弗雷德里克），马克Stenglein和拉梅什 Akkina（科罗拉多州立大学）参与了互补领域的工作，以协同在这个项目。

Project Summary / Abstract The AIDS pandemic caused by HIV-1 and to a lesser extent by HIV-2 resulted in more than 35 million deaths worldwide, with both these viruses now deeply entrenched in the human population. How these culprits arose during the 20th century from the long-preexisting benign ancient SIV viral strains is still a mystery. Several hypotheses have been put forward that include simple zoonotic transfer followed by spread, modern human migration spreading an otherwise isolated rural disease or inadvertent serial passage of the progenitor viruses in humans resulting in increased virulence. An experimental system that can test some of these hypotheses has been lacking until recently. With the advent of humanized mice (hu-mice) that harbor a transplanted human immune system, it has now become possible to address some key questions surrounding how a retrovirus native to non-human primates that existed through the millennia jumped the species barrier and evolved to give rise to the current human pandemic. Work in our laboratories and others have established a new generation of hu-mice that continuously generate human T cells, B cells, macrophages and dendritic cells de novo, and that are exquisitely sensitive to infection with HIV-1 and HIV- 2 giving rise to chronic viremia and CD4 T cell loss typical of AIDS. Thus, we are now in a unique position to directly evaluate the potential of ancestral SIV strains for human viral transmission, pathogenesis and evolution in a physiologically relevant in vivo human surrogate system. The primary aim of our studies is to exploit this unique in vivo model for serial passage of chimpanzee SIVcpz and sooty mangabey SIVsm viral strains, the progenitors of HIV-1 and HIV-2, respectively, and determine the genetic and phenotypic changes responsible for the emergence of the HIV viral strains. We recently derived promising preliminary data by successfully growing and adapting SIVsm and SIVcpz in hu-mice. Sequence data on the 2nd passage of SIVsm showed fixed mutations in gp41 and the 1st passage SIVcpz has shown sequence changes indicative of viral evolution. These emerging data point to the feasibility of our proposed studies and to reaching the exciting goal of understanding the genetic basis for emergence of both HIV types and thus shedding light on a long-standing mystery. In this work, we will serially passage SIVcpz and SIVsm in vivo in hu-mice to derive human adapted viruses that potentially represent fully evolved strains of HIV-1 and HIV-2 respectively, characterize the key pathogenic attributes, derive sequence data to identify adaptive sequence changes and assess the critical genomic changes in overcoming human restriction factors such as tetherin. To conduct these promising studies, we assembled an accomplished and enthusiastic team of collaborators Drs. Preston Marx (Tulane), Shelby O'Connor and David Evans (University of Wisconsin), Francoise Villinger (New Iberia Research Institute, Louisiana), Brandon Keele (NCI, Frederick), Mark Stenglein and Ramesh Akkina (Colorado State University) involved in complementary areas of work to synergize in this project.