National Institute for Viral Disease Control and Prevention, China CDC, Beijing, 102206, China.
Appl Microbiol Biotechnol. 2012 Oct;96(2):357-66. doi: 10.1007/s00253-012-4171-4. Epub 2012 Jun 9.
The currently recommended treatment for individuals exposed to rabies virus (RV) is post-exposure prophylaxis (PEP) through the combined administration of rabies vaccine and rabies immune globulin (RIG). Human monoclonal antibodies (mAbs) that neutralize RV offer an opportunity to replace RIG for rabies PEP. Here, a combinatorial human Fab library was constructed using antibody genes derived from the blood of RV-vaccinated donors. Selections of this library against purified RV virions resulted in the identification of 11 unique Fab antibodies specific for RV glycoprotein. Of the Fab antibodies, five were converted to full human IgG1 format. The human IgG antibodies revealed high binding affinity and neutralizing activities against RV fixed strains through a rapid fluorescent focus inhibition test in vitro as well as the early stage protective function after exposure to RV infection in vivo. Furthermore, epitope mapping and binding competition analysis showed that all of obtained human neutralizing and protective antibodies were directed to the antigenic site II of RV glycoprotein. Our results provide not only important insight into the protective immune response to RV in humans, but also more candidates eligible for use in a mAb cocktail aimed at replacing RIG for rabies post-exposure prophylaxis.
目前推荐给接触狂犬病病毒 (RV) 的个体的治疗方法是通过联合使用狂犬病疫苗和狂犬病免疫球蛋白 (RIG) 进行暴露后预防 (PEP)。中和 RV 的人源单克隆抗体 (mAb) 为替代 RIG 用于狂犬病 PEP 提供了机会。在这里，使用源自 RV 疫苗接种供体血液的抗体基因构建了组合人 Fab 文库。针对纯化的 RV 病毒粒子对该文库进行选择，导致鉴定出 11 种针对 RV 糖蛋白的独特 Fab 抗体。在 Fab 抗体中，有 5 种被转化为全人源 IgG1 形式。通过体外快速荧光焦点抑制试验以及在 RV 感染暴露后的早期保护作用，这些人源 IgG 抗体显示出对 RV 固定株的高结合亲和力和中和活性。此外，表位作图和结合竞争分析表明，所有获得的人中和和保护抗体均针对 RV 糖蛋白的抗原表位 II。我们的研究结果不仅为人类对 RV 的保护性免疫反应提供了重要的见解，而且还为用于替代 RIG 进行狂犬病暴露后预防的 mAb 鸡尾酒提供了更多合格的候选物。
