Monoclonal Antibodies in Biodefense: Ebola Viruses

描述(申请人提供)：用抗体进行被动免疫已被证明可以预防多种影响人类的病毒、细菌、真菌和寄生虫病。事实上，军事上需要有效的抗体预防药物，以防止武器化的生物武器制剂和其他具有生物武器潜力的人类病原体。这项建议提供了一种机制，用于建立发现和GMP生产保护性人类单抗(MAb)的过程。这一过程可以很容易地适应其他生物制剂，并用于应对新出现和再次出现的病原体。这项提案将把重点放在针对埃博拉病毒(EBOV)的人类单抗免疫疗法上。目前还没有针对EBOV的疫苗或疗法。建议中开发的单抗可以在工厂的GMP条件下生产，作为预防对策使用，为军事人员或平民提供即时和持续的(人免疫球蛋白血清半衰期~3周)保护，并可能在暴露后预防和/或治疗中具有价值。第一个目标是利用两种互补技术识别一组针对EBOV的新型人类单抗。一种是从血清阳性的幸存者中分离出单抗，另一种是针对在自然人类感染中可能不是免疫原性或免疫优势的表位产生一组不同的单抗。在第二个目标中，新的单抗将在快速植物表达系统中表达为来自不同动物物种的具有恒定区域的各种同种异型，EBOV模型适用于这些动物物种。在第三个目标中，将使用埃博拉感染的体外、小鼠和猕猴模型来确定抗原特异性、抗体亚型和来源抗体种类在预防和治疗中的作用。最终筛选出最适合玉米GMP生产的单抗(S)。由于免疫疗法可能需要储存数百万剂，这些产品必须以低廉的价格大量生产。植物生产比哺乳动物细胞培养生产要便宜得多，每英亩玉米可以生产千克量的单抗。在目前的农艺措施下，只需在更多耕种的英亩土地上播种，就可以廉价地扩大植物生产，以满足库存需求。

DESCRIPTION (provided by applicant): Passive immunization with antibodies has been shown to prevent a wide variety of viral, bacterial, fungal, and parasitic diseases that affect humans. Indeed, effective antibody prophylactics are in military demand for protection against weaponized biowarfare agents and other human pathogens with biowarfare potential. This proposal provides the mechanism for establishing a process for the discovery and GMP manufacture of protective human monoclonal antibodies (Mabs). This process can readily be adapted to other biowarfare agents and used to respond to emerging and re-emerging pathogens. This proposal will focus on human Mab immunotherapeutics for the Ebola viruses (EBOVs). There are currently no vaccines or therapies for EBOVs. Mabs developed in the proposal can be produced under GMP conditions in plant for use as prophylactic countermeasures, providing immediate and sustained (human IgG serum half-life ~ 3 weeks) protection of military personnel or civilians, and may also have value in post-exposure prophylaxis and/or therapy. The first aim is to identify a panel of novel human Mabs against EBOVs using two complementary techniques. One isolates Mabs from seropositive survivors and the other generates a diverse panel of Mabs against epitopes that may not be immunogenic or immunodominant in natural human infection. In the second aim, the novel Mabs will be expressed in a rapid plant expression system as a variety of isotypes with constant regions from the different animal species for which EBOVs models are available. In the third aim, the role of antigen specificity, antibody isotype and antibody species of origin will be determined for prophylaxis and therapy using in vitro, murine, and macaque models of Ebola infection. In the final aim, the best Mab(s) will be selected for initiation of GMP production in corn. Since immunotherapeutics may need to be stockpiled in millions of doses, these products must be manufactured inexpensively and in large quantities. Plant production is dramatically cheaper than mammalian cell culture production and kilogram quantities of Mab can be produced per acre of corn. Production in plants can be inexpensively scaled-up to meet stockpile needs by simply planting seed on more farmed acres of land with current agronomic practices.