Pathogenic determinants in the SIV envelope transmembrane cytoplasmic domain

HIV-1建立了一种持续性感染，其特征是在面对活跃的宿主时持续进行病毒复制 免疫反应、CD4细胞耗竭和最终的艾滋病。对于艾滋病的SIV模型，减毒病毒 提供了一个强有力的方法来了解致病性的基础，因为这些病毒可以 由主机控制。这些模型还提供了最好的证据，表明宿主免疫反应可以 当用致病性分离株攻击时，可以保护动物免受感染和/或疾病。 然而，即使是最佳表征的减毒病毒，其潜在的机制也是不确定的。 这种保护的减毒和免疫相关性是未知的。此外，当保护 实现，它通常是同源的，而不是异源分离物。我们的实验室已经证明， SIVmac239 Env胞质尾区中保守的YxxF运输基序的突变产生了深刻的 减毒表型，使这种高致病性病毒易受宿主免疫控制。我们有 还显示受感染的动物被保护免受SIVmac239同源攻击的感染， 并且显著地，能够控制异源攻击病毒。我们建议延长我们的初步 导致该模型在细胞和病毒学水平的体外研究和非人的体内研究中 灵长类动物建立YxxF突变的细胞效应、减毒和宿主免疫之间的联系。 控制提出了四个目标，两个用于该模型的细胞生物学和病毒学的体外研究， 两个用于发病机理和宿主免疫应答的体内研究。目标1将描述相互作用 YxxF和其他最近发现的TM贩运信号，并确定细胞伙伴和贩运 相关主要细胞类型的通路。目的#2将评价TM尾突变对病毒体的影响 结构、组成、感染力和复制能力，并探索增加 中和敏感性的这些病毒注意到在我们的初步结果。目标#3将全面 评估急性感染期间粘膜淋巴部位的早期和晚期感染事件， 细胞被感染，引发了什么样的炎症反应，以及在这种情况下观察到的衰减是否 模型影响YxxF突变体经粘膜传播的能力。目标#4将评估细胞和 对AGY和其他TM尾突变体的体液免疫应答，并确定存在哪些差异 与SIVmac239在广度、特异性和幅度上进行比较。将在评估之前和之后进行评估 用致病性异源病毒攻击，以确定异源病毒的免疫相关性 保护总的来说，我们的工作表明，合理设计的细胞运输信号突变， Env可被利用来破坏病毒/宿主平衡和感染的结果，并且应该是一种高度有效的治疗方法。 致病机理和疫苗研究信息模型。

HIV-1 establishes a persistent infection characterized by ongoing viral replication in the face of vigorous host immune responses, CD4 cell depletion and ultimately AIDS. For SIV models of AIDS, attenuated viruses have provided a powerful approach to understand the basis of pathogenicity, as these viruses can be controlled by the host. These models have also provided the best evidence that host immune responses can be elicited that can protect animals from infection and/or disease when challenged with pathogenic isolates. However, for even the best characterized attenuated viruses, the mechanism(s) that underlie their attenuation and the immune correlates of this protection are unknown. Moreover, when protection is achieved, it is typically for homologous rather than heterologous isolates. Our laboratory has shown that mutations in a conserved YxxF trafficking motif in the SIVmac239 Env cytoplasmic tail produce a profoundly attenuated phenotype that renders this highly pathogenic virus susceptible to host immune control. We have also shown that infected animals are protected from infection with a homologous challenge with SIVmac239, and remarkably, are able to control a heterologous challenge virus. We propose to extend our preliminary results in this model to in vitro studies at the cellular and virologic levels and in vivo studies in nonhuman primates to establish the links between cellular effects of the YxxF mutations, attenuation, and host immune control. Four aims are proposed, two for in vitro studies of the cell biology and virology of this model, and two for in vivo studies of pathogenesis and the host immune responses. Aim#1 will characterize interactions of the YxxF and other recently identified TM trafficking signals and identify cellular partners and trafficking pathways on relevant primary cell types. Aim #2 will evaluate the effects of TM tail mutations on virion structure, composition, infectivity, and replicative capacity and explore mechanisms for increased neutralization sensitivity of these viruses noted in our preliminary results. Aim #3 will comprehensively evaluate early and late events of infection in mucosal lymphoid sites during acute infection, determine what cells are infected, what inflammatory responses are elicited, and whether the attenuation observed in this model affects the ability of YxxF mutants to be transmitted mucosally. Aim #4 will evaluate cellular and humoral immune responses to AGY and other TM tail mutants and determine what differences exist compared to SIVmac239 in breadth, specificity and magnitude. Responses will be assessed before and after challenge with a pathogenic heterologous virus to determine what are the immune correlates of heterologous protection. Collectively, our work shows that rationally designed mutations in cellular trafficking signals in Env can be exploited to disrupt the viral/host balance and the outcome of infection and should be a highly informative model for pathogenesis and vaccine research.