New Approaches To Passive And Active Immunoprophylaxis

被动和主动免疫预防的新方法

• 批准号: 6503691
• 负责人: Robert H. Purcell
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6503691
• 关键词: Callithricidae; Hepatovirus; Macaca mulatta; Pan; active immunization; attenuated microorganism; biotechnology; hepatitis A; hepatitis B; hepatitis B virus group; hepatitis C virus; hepatitis vaccine; hepatitis virus; immunomodulators; live vaccine; nonhuman therapy evaluation; passive immunization; tissue /cell culture; vaccine development; vector vaccine; virus replication

The HVS in collaboration with SmithKline Beecham, Rixensart, Belgium, has developed several candidate live attenuated HAV vaccines. In addition, the HVS has developed a candidate recombinant hepatitis E vaccine that is highly promising and that is currently in clinical trials. The HVS is studying the technology of DNA vaccines with a model system based upon hepatitis B virus (HBV) vaccine, a vaccine with which the HVS has had extensive experience. We have tested the efficacy of an immunostimulant (CpG) as an adjuvant for DNA vaccines, as well as for protein vaccines. In addition, the utility of DNA vaccines for the control of hepatitis C virus (HCV) has been explored. A DNA vaccine based on the E2 envelope protein of HCV proved to be highly immunogenic in mice and rhesus monkeys and moderately immunogenic in chimpanzees, but the chimpanzees were not fully protected when they were challenged with live HCV. A similar approach has been utilized in the study of a DNA vaccine based on the E1 envelope protein of HCV. Various constructs of the E1 gene were prepared as DNA vaccines (expression vector plasmids) and as vectored vaccines (recombinant vaccinia). Mice were vaccinated with the DNA vaccine ("prime"), followed by vaccination with the recombinant vaccinia viruses ("boost"). The mice had excellent immune responses to the DNA vaccine as well as to the vaccinia boost. Based on these results, the studies will be extended to non-human primates, including chimpanzees, to determine if such immune responses are protective. Passive immunoprophylaxis has also been an important public health tool. For example, normal immunoglobulin has been important in the prevention of hepatitis A. However, monoclonal preparations could be more potent, tailored to specific neutralization epitopes and highly consistent in potency. We have prepared combinatorial libraries from the bone marrow of chimpanzees that had been experimentally infected in sequence with each of the five human hepatitis viruses. Chimpanzee globulins are virtually identical to human immunoglobulins, making them attractive choices for immunoprophylactic and immunotherapeutic agents. To date, we have isolated monoclonal immunoglobulins that react with HAV, HBV, HDV and HEV. In other studies, we have recovered human monoclonal antibodies that react with HCV. Many of the monoclonal antibodies described above are neutralizing and their production is being scaled up for tests of passive immunoprophylaxis in chimpanzees. Similar construction of combinatorial libraries from bone marrow is being carried out for chimpanzees that have been experimentally infected with dengue viruses 1 through 4 and the Norwalk virus, one of the most common causes of adult viral gastroenteritis. In some cases (dengue fever) recombinant monoclonal antibodies may prove to be important prophylactic and therapeutic agents. In other cases (Norwalk virus), the monoclonal antibodies will be useful as diagnostic reagents. We plan to extend these studies to other viruses of interest that can be experimentally administered to chimpanzees.

HVS与比利时里克森萨尔的SmithKline Beecham合作开发了几种候选的减毒活HAV疫苗。此外，HVS还开发了一种非常有前途的候选重组戊型肝炎疫苗，目前正在进行临床试验。HVS正在研究DNA疫苗技术，其模型系统基于HVS具有丰富经验的B肝炎病毒（HBV）疫苗。我们已经测试了免疫刺激剂（CpG）作为DNA疫苗以及蛋白质疫苗的佐剂的功效。此外，DNA疫苗用于控制丙型肝炎病毒（HCV）的效用已被探索。基于HCV E2包膜蛋白的DNA疫苗在小鼠和恒河猴中被证明具有高度免疫原性，在黑猩猩中具有中等免疫原性，但当黑猩猩被活HCV攻击时，它们没有得到完全保护。类似的方法已用于基于HCV的E1包膜蛋白的DNA疫苗的研究。将E1基因的各种构建体制备为DNA疫苗（表达载体质粒）和载体疫苗（重组牛痘）。用DNA疫苗接种小鼠（“初免”），然后用重组牛痘病毒接种（“加强”）。小鼠对DNA疫苗和牛痘疫苗都有很好的免疫反应。基于这些结果，研究将扩展到包括黑猩猩在内的非人类灵长类动物，以确定这种免疫反应是否具有保护性。 被动免疫预防也是一种重要的公共卫生工具。例如，正常的免疫球蛋白在预防甲型肝炎中一直是重要的。然而，单克隆制剂可能更有效，针对特定的中和表位定制，并且效力高度一致。我们已经从黑猩猩的骨髓中制备了组合文库，这些黑猩猩已经被实验性地依次感染了五种人类肝炎病毒中的每一种。黑猩猩球蛋白几乎与人免疫球蛋白相同，使其成为免疫预防剂和免疫抑制剂的有吸引力的选择。迄今为止，我们已经分离出与HAV、HBV、HDV和HEV反应的单克隆免疫球蛋白。在其他研究中，我们已经回收了与HCV反应的人单克隆抗体。上述许多单克隆抗体具有中和作用，其生产正在扩大，用于黑猩猩的被动免疫预防试验。类似的骨髓组合文库的构建也在黑猩猩中进行，这些黑猩猩已经实验性地感染了登革病毒1至4和诺瓦克病毒，诺瓦克病毒是成人病毒性胃肠炎最常见的原因之一。在某些情况下（登革热），重组单克隆抗体可能被证明是重要的预防和治疗剂。在其他情况下（诺瓦克病毒），单克隆抗体将用作诊断试剂。我们计划将这些研究扩展到其他感兴趣的病毒，这些病毒可以实验性地给予黑猩猩。