SIV Deltavif Reservoirs in Vivo

描述（由申请方提供）：猴免疫缺陷病毒（SIV）动物模型为评估人类免疫缺陷病毒（HIV）/AIDS的新型抗病毒策略提供了独特而重要的机会。在动物模型中仔细阐明HIV辅助基因在体内的功能对于设计和开发用于治疗人类免疫缺陷病毒-1（HIV-1）感染的靶向干预策略至关重要。辅助基因vif存在于除马传染性贫血病毒（EIAV）之外的所有已知慢病毒的基因组中，并且已经显示对于多种动物慢病毒而言是体内和体外有效病毒复制所需的。Vif促进HIV-1和SIV病毒感染的机制最近才被阐明。Vif通过靶向细胞胞苷脱氨酶APOBEC 3G进行蛋白质体降解来抑制该细胞蛋白的病毒体掺入。如果掺入病毒体中，APOBEC 3G通过诱导新合成的负链病毒DNA中的C至U突变来严重限制病毒RNA的逆转录。基于体外实验的这些发现进一步证明了Vif对有效慢病毒复制的需求，并将这种病毒因子作为抗病毒治疗的潜在靶点。我们最近的研究表明，恒河猴接种前病毒SIV vif突变体表现出强烈的病毒特异性细胞免疫应答沿着低水平的抗病毒抗体应答。总之，这些发现意味着wf缺失病毒的复制在宿主中是持久的，尽管在极低的水平。此外，这些观察结果强烈支持了体内存在允许SIV vif阴性病毒感染的储库或特定靶细胞群的假设。该提案旨在使用SIV vif缺失突变体感染恒河猴来鉴定允许体内SIV-vif感染的靶细胞群，并检查这些细胞群的APOBEC 3A-H基因表达以及APOBEC 3F和APOBEC 3G蛋白表达。此外，该提案包括对体内多种淋巴组织内特定SIV/HIV靶细胞群中APOBEC 3A-H表达的深入分析。考虑到W-APOBEC 3相互作用作为抗病毒治疗靶点的潜在意义，明确了解宿主中APOBEC 3蛋白家族的表达至关重要，特别是对于表征APOBEC 3（A-H）可能较低或不存在的细胞群，以及在Vif靶向抗病毒治疗中可能支持HIV-1复制的细胞群。因此，来自这些提出的实验的发现可能对靶向Vif和Vif与细胞因子的相互作用的抗病毒治疗剂的设计和预期具有显著影响（即，例如，APOBEC 3蛋白家族）。

DESCRIPTION (provided by applicant): The simian immunodeficiency virus (SIV) animal model presents a unique and significant opportunity for assessing novel antiviral strategies for human immunodeficiency virus (HIV)/AIDS in humans. Careful elucidation of HIV accessory gene functions in vivo in an animal model will be crucial to the design and development of targeted intervention strategies useful for treatment of human immunodeficiency virus-1 (HIV-1) infection of humans. The accessory gene vif is present in genomes of all known lentiviruses, with the exception of equine infective anemia virus (EIAV), and has been shown to be required for efficient viral replication both in vivo and in vitro for multiple animal lentiviruses. Mechanisms by which Vif functions to facilitate viral infectivity for both HIV-1 and SIV have only recently been elucidated. Vif inhibits virion incorporation of a cellular cytidine deaminase, APOBEC3G, by targeting this cellular protein for proteosomal degradation. If incorporated into virions, APOBEC3G severely restricts reverse transcription of viral RNA by inducing C to U mutations in newly synthesized negative strand viral DNA. These findings based on in vitro experiments further demonstrate the requirement of Vif for efficient lentivirus replication and distinguish this viral factor as a potential target for antiviral therapies. Our recent studies indicate that rhesus macaques inoculated with a proviral SIV vif mutant exhibit strong virus-specific cellular immune responses along with low level antiviral antibody responses. Taken together, these findings imply that replication of a wf-deleted virus is persistent in the host, although at extremely low levels. Furthermore, these observations strongly support the hypothesis of the presence of a reservoir or a specific population of target cells permissive for SIV vif-negative virus infection in vivo. This proposal intends to use infection of rhesus macaques with a SIV vif deletion mutant to identify target cell populations permissive for SIV-vif infection in vivo and to examine such populations for expression of APOBEC3A-H genes, as well as APOBEC3F and APOBEC3G protein expression. Moreover, this proposal includes an in depth analysis of APOBEC3A-H expression in specific SIV/HIV target cell populations within multiple lymphoid tissues in vivo. Given the potential significance of W-APOBEC3 interactions as a target for antiviral therapies, a clear understanding of the expression of the APOBEC3 family of proteins in the host, is critical, particularly for characterizing cell populations where APOBEC3(A-H) may be low or absent and which may support HIV-1 replication in the face of Vif-targeted antiviral therapies. Accordingly, findings from these proposed experiments may have significant impact on the design and expectation of antiviral therapeutics that target Vif and Vif interactions with cellular factors (i. e., APOBEC3 family of proteins).