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，由于延长了母乳喂养，艾滋病毒的母婴传播率达到约35%，全世界约有70万婴儿感染。用少量广谱中和单抗(MAb)被动免疫治疗挑战猕猴的SIV，预示着输注中和单抗可以防止这种传播。然而，所需的MAB数量将超过目前以发酵罐为基础的生产系统，用于MAB生产的替代系统是高度优先的。由于最近的创新，瞬时植物(Nicitiana Bentamiama)表达平台现在代表了现有的一些最快速、最具成本效益和最多产的平台；能够在几周内生产出克的重组单抗。在第一阶段可行性研究中，2G12、2F5、4E10、B12、M43和M9单抗在80-100 mg/kg的叶片中瞬时产生高甘露糖和复杂糖型(单链抗体M9除外)，每个单抗都表现出相似的中和滴度，并且在B12的情况下，中和效价高于CHO来源的单抗，尽管在抗体依赖的细胞毒性活性方面观察到了差异。在第二阶段，除了第一阶段的B12和2G12外，将在p19增强型植物表达系统(200-500 mg/kg)中生产三种新的广泛和有效的单抗(PG9、PG16、VRC01)的高甘露糖、复合体和11，3-岩藻糖/21，2-木糖负/低糖形式，并在体外评估它们的中和和F3介导的抗体效应活性(ADCC和ADCVI)。将生产600毫克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。将静脉注射单一单抗和混合单抗。或者南加州大学。每周和阴道挑战一次低剂量的SHV，每两周一次，以更接近于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。 与公共卫生的相关性：随着发展中世界艾滋病毒母婴传播的数量不断增加，生产和使用具有很强中和活性的单抗进行免疫治疗是一个高度优先事项。然而，目前还没有生产这么大数量的设备。在第一阶段，我们证明了单抗可以在新的瞬时植物表达系统中高水平地快速产生，并且具有与传统的CHO衍生形式相似(或更好)的中和活性。在第二阶段，我们将使用增强的瞬时表达系统来产生大量新的有效单抗，并评估它们保护猕猴免受SHV病毒感染的能力。

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.