Bispecific-Antibody-Drug Conjugates for Selective Targeting and Activation of the HIV Latent Reservoir

项目摘要/摘要 潜伏的HIV蓄水池，主要由HIV感染的和长期存活的CD4+休眠亚群组成 记忆T细胞是在感染的最早阶段建立的。虽然目前可用的抗逆转录病毒药物 治疗(ART)可以将血液中的艾滋病毒水平降低到无法检测的水平，但不能消除潜在的 蓄水池，从而对治愈感染造成了重大障碍。许多潜伏期反转剂 (LRAs)在体外显示出活性，但到目前为止，在临床试验中，所有LRAs对潜在储存库的影响都很小或没有影响。 因为增加LRA的剂量在目前的形式下是令人望而却步的，因为 全身性毒性，特定靶向和激活潜伏的艾滋病毒储存库的替代战略是 需要的。因此，我们建议利用单抗(MAbs)的高度特异性， 通过构建针对HIV潜伏期的双特异性抗体进一步提高其特异性 水库。我们将设计一组双特异性抗体，能够针对狭小的CD4+亚群 静止的记忆T细胞，已被描述为血液和组织中可能的艾滋病毒储存细胞。我们 然后将一组LRA偶联到每个有希望的双特异性抗体上，以传递这些试剂 优先于潜伏感染的细胞。评估我们设计的所有双特异性抗体的活性 和抗体-药物结合物(ADC)，我们将采用迭代方法来评估结合亲和力和亲和力， LRA传递的选择性，以及在体外或体外从潜伏储存库中激活HIV。ADC带有 最有希望的体外或体外特性将进一步评估它们对潜在储集层的影响 活体采用人性化的小鼠模型进行HIV感染和治疗。的基本假设 建议的研究是使用双特异性抗体在含有LRA的细胞群体中浓缩LRA 潜伏的HIV，虽然最大限度地减少了接触无病毒细胞的机会，但可以显著增加治疗效果 LRA指数上升了几个数量级。我们相信，我们的建议提供了一个有前途的和新颖的 高度特异和有效地激活艾滋病毒储存细胞的策略，我们相信其中一个或几个 我们设计的抗体药物结合物可能成为多管齐下的方法的关键组成部分 消除潜伏蓄水池，治愈HIV-1感染。

PROJECT SUMMARY/ABSTRACT Latent HIV reservoirs, primarily comprised of HIV-infected and long-lived subpopulations of CD4+ resting memory T cells are established during the earliest stage of infection. While currently available antiretroviral therapies (ART) can reduce the level of HIV in blood to an undetectable level, they cannot eliminate the latent reservoir, thereby imposing a major obstacle to curing the infection. A number of latency reversal agents (LRAs) has shown activity in vitro, but all have little or no impact on the latent reservoir in clinical trials to date. Because increasing the doses of LRAs is prohibitive in their current forms due to the potential for increased systemic toxicity, alternative strategies for the specific targeting and activation of the latent HIV reservoir are needed. We therefore propose to harness the exquisite specificity of monoclonal antibodies (mAbs) and to further increase their specificity through the construction of bispecific antibodies for targeting the HIV latent reservoir. We will engineer a panel of bispecific antibodies capable of targeting the narrow subsets of CD4+ resting memory T cells that have been characterized as the likely HIV reservoir cells in blood and tissues. We will then conjugate a panel of LRAs to each of the promising bispecific antibodies to deliver such agents preferentially to the latently infected cells. To evaluate the activity of all of our engineered bispecific antibodies and antibody-drug conjugates (ADCs), we will take an iterative approach to assess binding affinity and avidity, selectivity of LRA delivery, and HIV activation from the latent reservoir in vitro or ex vivo. The ADCs with the most promising in vitro or ex vivo properties will be further evaluated for their impact on the latent reservoir in vivo using a humanized mouse model of HIV infection and treatment. The underlying hypothesis of the proposed studies is that the use of bispecific antibodies to concentrate LRAs in cell populations harboring latent HIV, while minimizing the exposure to cells that are virus free, could markedly increase the therapeutic index of LRAs by several orders of magnitude. We believe that our proposal offers a promising and novel strategy for highly specific and potent activation of HIV reservoir cells, and it is our belief that one or several of our engineered antibody drug conjugates could become a key component in a multi-pronged approach to eliminating the latent reservoir and curing HIV-1 infection.