Immunotherapeutics for Treatment of Flavivirus Infection

描述（由申请人提供）：自1999年在美国出现以来，西尼罗河病毒（WNV）已造成大量鸟类和马匹死亡，近1000人死亡。目前尚无有效的治疗方法，迫切需要一种强有力的治疗方法。本项目的目的是开发和评估重组人单克隆抗体预防和治疗致命西尼罗河病毒感染的疗效。我们利用噬菌体显示屏制备了针对西尼罗河病毒包膜蛋白的重组人单克隆单链可变片段（scFv），并在体外和体内对这些抗体进行了表征。该程序不需要免疫选择，并且可以识别在感染或抗原免疫过程中通常无法识别的新表位，这是其他抗体开发策略无法做到的。我们已经证明这些抗体-特别是scfv# 11，我们的模型抗体-在体外中和西尼罗河病毒和相关黄病毒，并且在西尼罗河病毒小鼠模型中感染前具有保护作用，感染后具有治疗作用。本研究拟制备scfv# 11作为完整抗体，并证明其抗西尼罗河病毒的有效性，以及对登革热病毒和其他黄病毒的交叉保护中和作用。此外，我们将生产和鉴定额外的重组抗体，以开发两种抗体的协同组合，以增强对西尼罗河病毒和其他黄病毒感染的中和和治疗。重组抗体将完全是人源性的，生产速度快，效价高，不含血源性病原体，有望作为抗黄病毒感染的临床试剂进一步开发。

DESCRIPTION (provided by applicant): Since its appearance in the United States in 1999, West Nile virus (WNV) has caused the deaths of large numbers of birds and horses and close to 1000 humans. There is currently no effective therapy available, and a potent therapy is urgently needed. The goal of this project is to develop and evaluate the efficacy of recombinant human monoclonal antibodies for the prophylaxis and treatment of lethal WNV infection. We have produced recombinant human monoclonal single chain variable fragments (scFv) against the WNV envelope protein using a phage display screen, and characterized these antibodies both in vitro and in vivo. This procedure does not require immune selection, and can identify novel epitopes that are not normally recognized during infection or immunization with antigen - something that is not possible with other antibody development strategies. We have shown that these antibodies - particularly scFv #11, our model antibody for development - neutralize WNV and related flaviviruses in vitro, and are both protective before infection and therapeutic after infection in the mouse model of WNV. Here we propose to produce scFv#11 as a complete antibody and demonstrate its efficacy against WNV, as well as its cross-protective neutralization of dengue virus and other flaviviruses. In addition, we will produce and characterize additional recombinant antibodies to develop a synergistic combination of two antibodies for enhanced neutralization and therapy against WNV and other flavivirus infections. The recombinant antibodies will be fully human, produced rapidly and in high titer, free of blood-borne pathogens, and will be promising candidates for further development as a clinical reagent to combat flaviviral infection.