Exploring antibody-Fc effector function in humanized mouse models of HIV latency

 描述（由申请人提供）：目前相当重视从感染者中根除HIV的策略。虽然许多努力集中在使用小分子重新激活整合的前病毒，但第二种可能性是使用对不同的HIV毒株和进化枝具有高度效力和活性的广泛中和抗体（bNAb）。最近的证据表明，bNAb在停止抗逆转录病毒治疗（ART）后延迟病毒反弹的能力表明，这些抗体可能能够清除或去除在其表面上表达包膜糖蛋白的细胞，有效地减少持续感染细胞的池大小。我们建议研究bNAb在支持抗体效应子功能的ART抑制HIV感染的新型人源化模型中积极消除或减少持久性病毒储库的大小的作用。 在三个具体目标中的第一个中，鉴于目标2和3中所述的动物模型中的下游肌内应用，我们将构建编码三种第二代bNAb的重链和轻链的“内脏”或辅助依赖性腺病毒（HDAd）载体。在第二个目标中，将在HIV感染的人源化BLT小鼠中测试这些载体化的bNAB，其中病毒载量将通过ART抑制至不可检测的水平，用于通过基因组DNA qPCR和病毒生长测定来测量潜伏病毒池大小。特别是，具有活性补体和功能性自然杀伤细胞的新型人源化小鼠模型将用于评估bNAb效应子功能在缩小持续感染储库中的作用。 在最后的目标中，将测试载体化的bNAb在体内收缩病毒储库的能力。 使用来自ART抑制的HIV+患者的外周血白细胞衍生的人源化小鼠，血浆病毒载量不可检测。 基于在本申请的R21阶段进行的研究，我们预期确立bNAb效应子活性靶向持久性病毒储库的关键作用。申请的R33阶段将这些研究扩展到检测HDAs中编码的四环素可调节bnAb，这可能是由于HdAd的大携带能力（约30 kb）。除了探索更新，更有效的bNAb，我们还将测试使用最近描述的eCD 4-IG，编码可溶性CD 4-IG和CCR 5肽模拟物和ARM-H，这是二价小分子，能够结合gp 160的CD 4结合口袋，也招募抗二硝基酚抗体的效应活性。这种使用编码bNAb的HDAs的方法也可以与潜伏期逆转剂组合，以清除感染的细胞。这些调查的结果应该会加速 bNAb作为ART辅助治疗HIV疾病的用途，由于消除或预防持续感染细胞的再活化，具有功能性根除的潜力。

 DESCRIPTION (provided by applicant): There is currently considerable emphasis on strategies for eradicating HIV from infected individuals. Although much effort is focused on reactivating integrated provirus using small molecules, a second possibility is using broadly neutralizing antibodies (bNAbs) that are highly potent and active against diverse strains and clades of HIV. Recent evidence demonstrating the ability of bNAbs in delaying viral rebound after stopping antiretroviral treatment (ART) indicate that these antibodies may be able to clear or remove cells expressing envelope glycoprotein on their surface, effectively reducing the pool size of persistently-infected cells. We propose to investigate a role for bNAbs in actively eliminating or reducing the size of the persistent viral reservoir, in novel humanized models of ART-suppressed HIV infection that support antibody-effector function. In the first of three specific aims, we will construct `gutted' or helper-dependent adenoviral (HDAd) vectors, encoding the heavy and light chains of three second-generation bNAbs, in view of the downstream intramuscular application in animal models described in Aims 2 and 3. In the second aim, these vectored bNABs will be tested in HIV-infected humanized BLT mice, in which viral loads will be suppressed to undetectable levels by ART, for measurements of the latent viral pool size by genomic DNA qPCR and viral outgrowth assays. In particular, novel humanized mouse models that have active complement and functional natural killer cells will be used to assess the role of bNAb effector function in shrinking the persistently infected reservoir. In the final aim, the vectored bNAbs will be tested for their ability to shrink viral reservoirs in humanized mice derived using peripheral blood leukocytes from ART-suppressed HIV+ patients with undetectable plasma viral loads. On the basis of the investigations to be conducted in the R21 phase of this application, we anticipate establishing a critical role for bNAb-effector activit targeting persistent viral reservoirs. The R33 phase of the application will extend these studies to the testing of tetracycline-regulable bnAbs encoded in HDAds, possible due to large carrying capacity of HdAds (~30 kb). In addition to exploring newer, more potent bNAbs, we will also test the use of the recently described eCD4-Ig, that encodes both soluble CD4-Ig and a CCR5 peptidomimetic and ARM-Hs, which are bivalent small molecules capable of binding the CD4 binding pocket of gp160 and also recruiting anti-dinitrophenol antibodies for effector activity. This approach of using HDAds encoding bNAbs may also be combined with latency reversal agents, in order to clear out infected cells. The results of these investigations should accelerate the use of bNAbs as an adjunct to ART in the treatment of HIV disease, with the potential for functional eradication due to elimination or prevention of reactivation of persistently-infected cells.