Passive immunotherapy using plant-derived broadly HIV-1 neutralizing MAbs to prev

描述（由申请人提供）：在没有具体干预措施的情况下，随着母乳喂养的延长，艾滋病毒母婴传播率达到约35%，全世界约有70万婴儿感染。在SHIV攻击的猕猴中使用少量广泛中和的单克隆抗体（MAb）的被动免疫疗法预示着中和MAb的输注能够预防这种在人类中的传播。然而，所需的单克隆抗体的量将压倒当前基于发酵的生产系统，并且用于单克隆抗体生产的替代系统是高度优先的。由于最近的创新，瞬时植物（烟草）表达平台现在代表了一些最快速，最具成本效益和生产力的存在;能够在数周内产生克重组单克隆抗体。在I期可行性研究中，2G 12、2F 5、4 E10 b12、m43和m9 MAb的高甘露糖和复合糖型以80-100 mg/kg叶瞬时产生（scFv m9除外），并且各自表现出相似的中和滴度，并且在b12的情况下，比其CHO衍生的对应物更好的中和滴度，尽管在抗体依赖性细胞毒性活性中观察到差异。在II期，三种新的广谱有效单抗的高甘露糖、复合糖和11，3-岩藻糖/21，2-木糖阴性/低糖型（PG 9、PG 16、VRC 01），除来自I期的b12和2G 12外，将在p19增强的植物表达系统中产生（200- 500 mg/kg），并在体外评估其中和和F3介导的抗体效应子活性（ADCC和ADCVI）。将生产600 mg具有最佳中和活性的这些形式，用于猕猴的药代动力学、免疫原性和保护研究。将静脉内或皮下注射单一MAb和MAb混合物。每周用低剂量SHIV进行阴道攻击，每两周一次，以更接近地模拟人类异性接触中遇到的剂量。这些结果将为过渡到人体试验提供临床前数据。 公共卫生相关性：随着发展中国家母婴传播艾滋病毒的数量不断增加，生产具有强中和活性的单克隆抗体并进行免疫治疗成为高度优先事项。然而，还没有生产如此大量的设备。在第一阶段，我们表明，单克隆抗体可以在一个新的瞬时植物表达系统中快速产生高水平，并具有类似（或更好）的中和活性作为常规CHO衍生形式。在第二阶段，我们将使用一个增强的瞬时表达系统，以产生大量的新的有效的单克隆抗体，并评估他们的能力，保护猕猴对SHIV病毒感染。

DESCRIPTION (provided by applicant): In the absence of specific intervention and with extended breast-feeding mother-to- child-transmission of HIV reaches a rate of ~35 % and infection of ~700,000 babies worldwide. Passive immunotherapy with a small number of broadly neutralizing monoclonal antibodies (MAbs) in SHIV challenged macaques bodes well for the ability of infusion of neutralizing MAb to prevent such transmission in humans. However the amount of MAb required would overwhelm current fermenter-based production systems and an alternate system for MAb production is a high priority. Due to recent innovations, transient plant (Nicotiana bentamiama) expression platforms now represent some of the most rapid, cost effective and productive in existence; capable of producing grams of recombinant MAbs in weeks. In the Phase I feasibility study, high mannose and complex glycoforms of 2G12, 2F5, 4E10 b12, m43 and m9 MAbs were transiently produced at 80-100 mg/kg leaves (except for the scFv m9) and each exhibited similar, and, in the case of b12, better neutralizing titers than their CHO-derived counterparts although differences were observed in antibody dependent cellular cytoxicity activity. In Phase II, high mannose, complex and 11,3-fucose/21,2-xylose-negative/low glycoforms of three new broad and potent MAbs (PG9, PG16, VRC01), in addition to b12 and 2G12 from Phase I, will be produced in a p19 enhanced plant expression system (200- 500mg/kg) and assessed for in vitro for both their neutralizing and F3-mediated antibody effector activity (ADCC and ADCVI). Six hundred mg of those forms with the best neutralizing activity will be produced for pharmacokinetics, immunogenicity and protection studies in macaques. Single MAbs and a cocktail of MAbs will be injected i.v. or s.c. weekly and vaginally challenged with a low dose of SHIV bi-weekly to more closely mimic doses encountered in human heterosexual exposure. These results will provide the preclinical data for transition into human trials. PUBLIC HEALTH RELEVANCE: With an ever increasing number of mother-to-baby-transmissions of the HIV virus in the developing world, the production of and immunotherapy with monoclonal antibodies that strongly neutralizing activity a high priority. However the facilities to manufacture such large amounts has not been available. In Phase I we showed that MAbs can be rapidly produced in a new transient plant expression systems in high levels and have similar (or better) neutralizing activity as the conventional CHO-derived forms. In Phase II we shall used an enhanced transient expression system to produce large amounts of new potent MAbs and assess their ability to protect macaques against SHIV virus infection.