Elicitation of HIV Broadly Neutralizing Antibodies from Engineered B cells

项目摘要/摘要 艾滋病毒广谱中和抗体(BNAbs)对病毒有效，但不能通过 由于人类B细胞抗原受体(BCR)库施加的遗传限制，疫苗接种。我们 最近发现，来自野生型小鼠的成熟原代B细胞可以在体外进行工程改造，以表达 BNab基因作为功能性抗原受体，这些细胞可以返回宿主并接种到 生成持久的bNab响应。因为这种动物模型不能支持HIV感染，无论是治疗性的还是 这些反应的保护效果尚未得到评估。这里描述的建议：1)探索 新的B细胞靶向方法，旨在改善B细胞在体内的工程和功能；2) 定义了疫苗参数和工程细胞的特性，这是可重复激发的 小鼠模型中持久的bNab反应；3)翻译我们成功的‘工程B细胞疫苗’ (EBcV)猕猴动物模型的原型，用于使用嵌合HIV/SIV病毒进行疗效测试 (切割器)。在非人类灵长类动物(NHP)中诱导的bNAbs将被测试其防止异源基因 2级病毒感染，抑制或维持对病毒血症的抑制，以评估EBCV的可能性 作为预防性疫苗或作为艾滋病毒的功能性治疗。这种方法可能具有重要的意义 与其他旨在持久地从肌肉或肝脏细胞分泌bNAbs的基因治疗策略相比，该策略具有优势。 当从修饰的B细胞中激发时，bNab反应应该是：1)能够在亲和力上成熟，以响应 快速进化的病原体；2)在有抗原存在的情况下增加滴度；3)以所有效应物的形式表达 同种异型；4)免疫系统耐受，因为它们来自B细胞；5)耐受 如果它们是有害的，应该使表达它们的细胞失活的机制。所有在此设计的研究 建议支持我们的长期目标，发展安全、有效和经济可行的工程 B细胞疫苗将从基因组修饰的B细胞中产生持久的HIV bNab反应作为一种策略 用于预防或艾滋病毒功能性治疗。

Project Summary/Abstract HIV broadly neutralizing antibodies (bnAbs) are effective against the virus, but cannot be elicited through vaccination due to genetic limitations imposed by the human repertoire of B cell antigen-receptors (BCRs). We have recently shown that mature primary B cells from wild-type mice can be engineered ex vivo to express bnAb genes as functional antigen receptors, and that these cells can be returned to the host and vaccinated to generate durable bnAb responses. Because this animal model cannot support HIV infection, therapeutic or protective efficacy of these responses have not yet been evaluated. The proposal described here: 1) Explores novel B cell targeting approaches that aim to improve how B cells are engineered and function in vivo; 2) Defines vaccine parameters and the properties of engineered cells required for reproducible elicitation of durable bnAb responses in the mouse model and; 3) Translates our successful ‘Engineered B cell Vaccine’ (EBcV) prototype to the rhesus macaque animal model for efficacy testing using chimeric HIV/SIV viruses (SHIVs). BnAbs elicited in non-human primates (NHP) will be tested for their ability to prevent heterologous tier-2 virus infection, suppress, or maintain suppression of viremia, in order to evaluate the potential for EBcVs to function as prophylactic vaccines or as an HIV functional cure. Such an approach may have significant advantages over other gene therapy strategies that aim to durably secrete bnAbs from muscle or liver cells. When elicited from modified B cells, bnAb responses should be: 1) able to mature in affinity in response to a rapidly evolving pathogen; 2) increase titers in the presence of antigen; 3) be expressed as all effector isotypes; 4) tolerated by the immune system because they originate from B cells and; 5) subject to tolerance mechanisms that should inactivate the cells expressing them if they are harmful. All studies designed in this proposal support our long-term goal, the development of safe, effective and economically feasible ‘Engineered B cell vaccines’ that would generate durable HIV bnAb responses from genome modified B cells as a strategy for prevention or HIV functional cure.