Pathogenic determinants of the SIV envelope transmembrane cytoplasmic domain

SIV包膜跨膜胞质结构域的致病决定因素

• 批准号: 7422256
• 负责人: James A Hoxie
• 金额: $ 64.37万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7422256
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Address; Affect; Animal Model; Animals; Arts; Attention; Attenuated; Biological; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; Cells; Cytopathology; Cytoplasmic Tail; Development; Disease; Disruption; Elements; Equilibrium; Event; Face; Flow Cytometry; Future; Goals; HIV; HIV Infections; HIV vaccine; HIV-1; Immune; Immune System Diseases; Immune response; Immune system; Immunity; In Vitro; Infection; Infection Control; Inflammatory Response; Integration Host Factors; Laboratories; Life; Link; Lymphoid; Macaca mulatta; Modeling; Monoclonal Antibodies; Mutation; Outcome; Pathogenesis; Pathogenicity; Peripheral; Phenotype; Proteins; Range; SIV; Science; Serum; Signal Transduction; Site; Specificity; Staining method; Stains; Structure; Tail; Technology; Vaccines; Viral; Viral Envelope Gene; Viral Load result; Virion; Virus; Virus Assembly; Work; attenuation; base; cell type; cytokine; design; enzyme linked immunospot assay; fitness; in vivo; insight; intracellular protein transport; mutant; novel; prevent; protein transport; response; tool; trafficking

DESCRIPTION (provided by applicant): 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 SIVs have provided powerful tools to understand pathogenesis, as they are viruses that can be controlled by the host. These models have also provided the best evidence that host immune responses 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 viruses, a scenario far removed from what will be required for an effective vaccine. Our laboratory has shown that mutations in a conserved GYxxX 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 SIVmac239 challenge, and remarkably, are able to control a heterologous challenge virus (SIVmac E660). We propose to extend our preliminary results in this model to characterize the effects of GYxxX mutations on the virus in vitro and, in rigorous in vivo studies in rhesus macaques, to identify the correlates of reduced pathogenicity and host immune control. Three aims are proposed. Aim #1 will evaluate the effects of TM tail mutations on virion structure, composition, infectivity, and fitness, and will explore the basis for the increased neutralization sensitivity of these viruses that we noted in our preliminary results. Aim #2 will comprehensively evaluate early and late events of infection in mucosal and other lymphoid sites to determine what cells are infected, what cytopathic effects occur, what inflammatory responses are elicited, and whether the attenuation observed in this model affects the ability of GYxxX mutants to be transmitted mucosally. Aim #3 will evaluate cellular and humoral immune responses to GYxxX mutants to 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 protection. These aims will also take advantage of viruses that have developed apparent compensatory mutations, as they will be powerful tools for future studies to address basic cellular mechanisms that underlie this model of attenuation and host immune control. Collectively, our work shows that rationally designed mutations in Env trafficking signals can be exploited to disrupt the viral/host balance and the outcome of infection. This model should be a highly informative for both pathogenesis and vaccine research.Project Narrative Three major obstacles in the development of an effective HIV vaccine have been 1) the lack of animal models that reproducibly show protection from genetically diverse challenge viruses; 2) a poor understanding of what components of the immune response are needed to prevent or control HIV infection; and 3) how a vaccine can be developed that will elicit these immune responses. Our application describes a new model of a live attenuated SIV in which a rationally designed mutation in the viral envelope gene creates a virus that can be completely controlled by the host immune system while conferring the ability to prevent or control infection by pathogenic viruses that are genetically different from the vaccine strain. The proposal describes plans to evaluate the pathological, immunological and virological aspects of this new model with state of the art technologies and addresses issues that are central to HIV vaccine science.

描述（由申请人提供）：HIV-1建立了一种持续感染，其特征是面对剧烈的宿主免疫反应，CD4细胞耗竭和最终AIDS，以持续的病毒复制为特征。对于SIV的艾滋病模型，衰减的SIV提供了强大的工具来理解发病机理，因为它们是可以由宿主控制的病毒。这些模型还提供了最好的证据，表明宿主免疫反应可以在受到致病性分离株的挑战时保护动物免受感染和/或疾病。但是，即使是最有特征的减毒病毒，其衰减和这种保护的免疫相关性的机制也未知。此外，当获得保护时，通常是用于同源性病毒而不是异源病毒，这种情况与有效疫苗所需的情况相去甚远。我们的实验室表明，SIVMAC239 ENV细胞质尾巴中保守的GYXXX运输基序中的突变产生的表型严重减弱，使这种高度致病的病毒易受宿主免疫控制。我们还表明，受感染的动物受到同源SIVMAC239挑战的感染，并且能够控制异源挑战病毒（Sivmac E660）。我们建议在该模型中扩展我们的初步结果，以表征Gyxxx突变对体外病毒的影响，并在恒河猴的严格体内研究中识别降低的致病性和宿主免疫控制的相关性。提出了三个目标。 AIM＃1将评估TM尾突变对病毒体结构，组成，感染性和适应性的影响，并将探索我们在初步结果中指出的这些病毒的中和敏感性增加的基础。 AIM＃2将全面评估粘膜和其他淋巴结部位感染的早期和晚期事件，以确定被感染的细胞，哪些细胞病变作用发生，哪些炎症反应是被引起的，以及该模型中观察到的衰减是否会影响Gyxxx突变体的能力。 AIM＃3将评估对GYXXX突变体的细胞和体液免疫反应，以确定与SIVMAC239相比，宽度，特异性和幅度的差异。在挑战之前和之后，将使用致病性异源病毒评估反应，以确定哪些免疫相关性是什么。这些目标还将利用开发出明显的补偿性突变的病毒，因为它们将是未来研究的强大工具，以解决这种衰减模型和宿主免疫控制模型的基本细胞机制。总的来说，我们的工作表明，可以利用在ENV运输信号中理性设计的突变，以破坏病毒/宿主的平衡和感染的结果。该模型对于发病机理和疫苗研究都应该是一个非常有用的信息。 开发有效HIV疫苗的三个主要障碍是1）缺乏可重复显示侵害遗传多样性挑战病毒的动物模型； 2）对预防或控制艾滋病毒感染的免疫反应的哪些组成部分的了解不足； 3）如何开发将引起这些免疫反应的疫苗。我们的应用描述了一种新型减毒SIV的新模型，在该模型中，病毒包膜基因中合理设计的突变产生了一种病毒，该病毒可以由宿主免疫系统完全控制，同时赋予与遗传菌株遗传上不同的病原病毒预防或控制感染的能力。该提案描述了使用最先进的技术来评估该新模型的病理，免疫和病毒学方面的计划，并解决了艾滋病毒疫苗科学核心的问题。