IN VITRO NEUTRALIZATION OF HCV WITH MONOCLONAL ANTIBODIES BEFORE ADMINISTRATION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。男性丙型肝炎病毒感染在大约85%的暴露个体中变为慢性感染。目前，美国估计有270万慢性感染者，全球估计有2亿人。目前还没有针对慢性丙型肝炎病毒感染的疫苗，干扰素和利巴韦林的联合治疗也很有限，但治疗成功的患者不到一半。由于这些原因，疫苗接种和/或免疫治疗可能是一种重要的替代方法。HCV的包膜蛋白是任何HCV疫苗的明显靶标。不幸的是，由于病毒的细胞培养系统较差，使用抗体的经典体外中和试验不能使用感染性病毒进行。测试抗体中和潜力的另一种方法是在体外过夜将HCV和抗体结合，然后通过接种黑猩猩来测试病毒的失活能力。最近，HIV-HCV假型颗粒被开发出来，可以潜在地用于在体外测试抗体的中和能力，而无需使用动物模型。然而，需要确定假型颗粒确实代表真正的HCV颗粒，并且中和这些假型颗粒的抗体也使用体内系统中和HCV。建立这一点的唯一方法是通过比较单克隆抗体在体外中和假型和体外中和试验，使用黑猩猩作为读出。本研究旨在进行这种比较。如果建立了牢固的相关性，黑猩猩确定中和抗体的需要将大大减少。100只黑猩猩感染剂量的单克隆HCV将与4种单克隆抗体中的每一种在体外过夜。在孵育之后，这些混合的药物将被静脉注射到黑猩猩体内。（总容积约5ml）。动物将每周放血并监测丙型肝炎病毒血症。如果8周后没有感染迹象，将用未中和的HCV挑战动物以证明感染性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Hepatitis C virus infections in man become chronic in approximately 85% percent of individuals exposed. At present there are an estimated 2.7 million chronically infected people in the United States and an estimated 200 million worldwide. There is no vaccine and therapy for chronic HCV infections is limited a combination of interferon and ribavirin, but treatment is successful in less than half the patients. For these reasons, vaccination and/or immuno-therapy may be an important alternative. The envelope proteins of HCV are an obvious target for any HCV vaccine. Unfortunately, due to poor cell culture systems for the virus, classic in vitro neutralization tests using antibodies cannot be performed using infectious virus. An alternative method to test the neutralization potential of an antibody is to combine HCV and antibody in vitro overnight and then test the inactivation of the virus by inoculation into chimpanzees. Recently, HIV-HCV pseudotype particles were developed that can be potentially used to test the neutralizing capabilities of antibodies in vitro without the use of an animal model. However, it needs to be established that the pseudotype particles do represent authentic HCV particles and that antibodies that neutralize these pseudotype particles also neutralize HCV using an in vivo system. The only way to establish this is through a comparison of monoclonal antibodies shown to neutralize pseudotypes in vitro with an in vitro neutralization test using the chimpanzee as a read-out. This study aims to make this comparison. If a firm correlation is established the need for chimpanzees to determine neutralizing antibodies will be greatly reduced. 100 chimpanzee infectious doses of monoclonal HCV will be combined with each of 4 monoclonal antibodies in vitro overnight. Following incubation the combined mixtures will be inoculated i.v. into chimpanzees. (Total volume approx 5ml). Animals will be bled weekly and monitored for HCV viremia. If no infection is indicated after 8 weeks the animals will be challenged with un-neutralized HCV to demonstrate infectivity.