CCR5 immunotoxins as components of HIV cure regimens

CCR5 免疫毒素作为 HIV 治疗方案的组成部分

• 批准号: 10664839
• 负责人: DENNIS J. HARTIGAN-O'CONNOR
• 金额: $ 30万
• 依托单位: TENDEL THERAPIES INC.
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-13 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10664839
• 关键词: Achievement; Adult; Animals; Antibodies; Autopsy; Benchmarking; Binding; Biological Assay; Bispecific Antibodies; Blood; CCR1 gene; CCR5 gene; CD3 Antigens; CD8-Positive T-Lymphocytes; Cells; Child; Chinese Hamster Ovary Cell; DNA; Data; Development; Disease remission; Dose; Drug Kinetics; Ensure; Evaluation; Excision; Fusion Toxin; Gene Expression; Genes; Genome; Government; HIV; HIV Infections; Hand; Immune system; Immunotoxins; In Vitro; Infant; Infection; Inflammatory; Interruption; Left; Length; Ligands; Light; Lymphoid Tissue; Lymphopenia; Macaca; Macaca mulatta; Modality; Monoclonal Antibody HuM291; N-terminal; Persons; Pharmaceutical Preparations; Pharmacodynamics; Production; Proteins; Provirus Integration; Publishing; RANTES; Reaction; Regimen; Research; Resistance; SIV; T-Lymphocyte; Testing; Time; Tissues; Toxic effect; Toxin; Vaccines; Viral; Virus; Withdrawal; cross reactivity; cytokine; effective therapy; experimental study; immune activation; in vitro testing; in vivo; in vivo evaluation; infant infection; manufacture; novel; receptor internalization; side effect; therapeutic vaccine; viral rebound

This project will establish proof-of-concept for CCR5 immunotoxins as HIV reservoir-depletion agents for use in cure strategies. HIV cure and remission strategies require elimination or reduction of the HIV reservoir. Approaches to reservoir reduction pursued by other groups include gene editing, i.e., direct removal of integrated provirus; latency reversal and an accompanying “kill” strategy; and “block-and-lock”, which is the effective elimination of reservoir cells by permanently suppressing gene expression. We instead pursued a strategy of directly eliminating potential reservoir cells in early infection, hypothesizing that most early reservoir cells express CCR5. Using a CD3/CCR5 bispecific antibody for reservoir depletion, we demonstrated delayed rebound in 4/7 and apparent cure of 2/7 SIV-infected infant macaques. One cured animal was necropsied 204 days after ART withdrawal and the second remains aviremic after 1.6 years. Both were depleted of CD8+ T cells to encourage viral rebound, but no rebound was seen. No proviral DNA was detected in circulating cells at any time point following ART withdrawal. Sensitive viral outgrowth assays failed to recover replication-competent virus. No proviral genomes were detected in the tissues of one sacrificed and apparently cured animal. Thus, results obtained so far show that these animals have achieved at least “functional” and perhaps sterilizing cure. The bsAb we employed achieves very efficient, transient depletion of CCR5+ cells but also causes an inflammatory reaction with cytokine production and temporary CD3+ lymphopenia. Tendel is therefore developing CCR5 immunotoxins for use in curative anti-HIV regimens. We hypothesize that CCR5 immunotoxins can achieve specific and minimally toxic depletion of CCR5+ T cells from blood, gut, and lymphoid tissues. SA1. Produce optimized immunotoxins based on CCR5 ligand-toxin fusions. Previously published immunotoxins were effective at high concentration in vitro but failed in-vivo tests. In this aim we develop new immunotoxins based on CCR5 ligands combined with linkers of different lengths and with various toxin candidates. We then test the candidates in vitro for specific lethality to CCR5-expressing cells. SA2. Test pharmacodynamics of development candidates in rhesus macaques, with a focus on CCR5 depletion from gut tissues without immune activation. Here the development candidates from Aim 1 are assessed in macaques and the results compared to depletion achieved by the benchmark bsAb, which is already shown to be potentially curative. Most importantly, these experiments test if candidate immunotoxins can achieve nearly 100% CCR5 depletion for at least several weeks in recipient animals. Our preliminary data show that the CCR5+ reservoir is an “Achilles’ heel” in early SIV and perhaps HIV infection. The proposed research will pursue proof-of-concept for novel Tendel immunotoxins.

该项目将建立 CCR5 免疫毒素作为 HIV 储存库耗​​尽剂的概念验证 用于治疗策略。 HIV 治愈和缓解策略需要消除或减少 HIV 水库。其他团体追求的减少储存库的方法包括基因编辑，即直接去除 整合原病毒；延迟逆转和伴随的“杀死”策略；和“阻止和锁定”，这是 通过永久抑制基因表达来有效消除储存细胞。 相反，我们采取了一种直接消除早期感染中潜在的储存细胞的策略，假设 大多数早期储存细胞表达 CCR5。使用 CD3/CCR5 双特异性抗体进行储库耗尽， 我们证明了 4/7 的 SIV 感染婴儿猕猴出现延迟反弹，2/7 的猕猴明显治愈。治愈一例 ART 停药后 204 天对动物进行尸检，第二只动物在 1.6 年后仍保持无病毒血症。两个都 耗尽 CD8+ T 细胞以促进病毒反弹，但没有看到反弹。没有原病毒DNA 在 ART 停药后的任何时间点均可在循环细胞中检测到。敏感的病毒生长检测失败 恢复具有复制能力的病毒。在一名处死者的组织中未检测到前病毒基因组 显然已经治愈的动物。因此，迄今为止获得的结果表明这些动物至少取得了成就 “功能性”甚至可能是杀菌疗法。 我们使用的 bsAb 可以非常有效地瞬时消除 CCR5+ 细胞，但也会导致 细胞因子产生的炎症反应和暂时性 CD3+ 淋巴细胞减少。因此，滕德尔是 开发 CCR5 免疫毒素用于治疗性抗 HIV 治疗方案。我们假设 CCR5 免疫毒素可以实现血液、肠道和肠道中 CCR5+ T 细胞的特异性且毒性最小的消耗。 淋巴组织。 SA1。基于 CCR5 配体-毒素融合产生优化的免疫毒素。先前发表 免疫毒素在体外高浓度下有效，但体内测试失败。为了这个目标，我们开发新的 基于CCR5配体与不同长度的接头和各种毒素相结合的免疫毒素 候选人。然后，我们在体外测试候选物对 CCR5 表达细胞的特异性杀伤力。 SA2。在恒河猴中测试开发候选药物的药效学，重点是 CCR5 在没有免疫激活的情况下从肠道组织中耗尽。这里目标 1 的开发候选者是 在猕猴中进行评估，并将结果与​​基准 bsAb 所实现的耗竭进行比较，即 已被证明具有潜在的治疗作用。最重要的是，这些实验测试候选免疫毒素是否 可以在受体动物中至少几周内实现近 100% CCR5 消耗。 我们的初步数据表明，CCR5+ 储存库是早期 SIV 甚至 HIV 的“致命弱点” 感染。拟议的研究将对新型 Tendel 免疫毒素进行概念验证。