Ngwuta Joan O, Chen Man, Modjarrad Kayvon, Joyce M Gordon, Kanekiyo Masaru, Kumar Azad, Yassine Hadi M, Moin Syed M, Killikelly April M, Chuang Gwo-Yu, Druz Aliaksandr, Georgiev Ivelin S, Rundlet Emily J, Sastry Mallika, Stewart-Jones Guillaume B E, Yang Yongping, Zhang Baoshan, Nason Martha C, Capella Cristina, Peeples Mark E, Ledgerwood Julie E, McLellan Jason S, Kwong Peter D, Graham Barney S
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
Sci Transl Med. 2015 Oct 14;7(309):309ra162. doi: 10.1126/scitranslmed.aac4241.
Respiratory syncytial virus (RSV) is estimated to claim more lives among infants <1 year old than any other single pathogen, except malaria, and poses a substantial global health burden. Viral entry is mediated by a type I fusion glycoprotein (F) that transitions from a metastable prefusion (pre-F) to a stable postfusion (post-F) trimer. A highly neutralization-sensitive epitope, antigenic site Ø, is found only on pre-F. We determined what fraction of neutralizing (NT) activity in human sera is dependent on antibodies specific for antigenic site Ø or other antigenic sites on F in healthy subjects from ages 7 to 93 years. Adsorption of individual sera with stabilized pre-F protein removed >90% of NT activity and depleted binding antibodies to both F conformations. In contrast, adsorption with post-F removed ~30% of NT activity, and binding antibodies to pre-F were retained. These findings were consistent across all age groups. Protein competition neutralization assays with pre-F mutants in which sites Ø or II were altered to knock out binding of antibodies to the corresponding sites showed that these sites accounted for ~35 and <10% of NT activity, respectively. Binding competition assays with monoclonal antibodies (mAbs) indicated that the amount of site Ø-specific antibodies correlated with NT activity, whereas the magnitude of binding competed by site II mAbs did not correlate with neutralization. Our results indicate that RSV NT activity in human sera is primarily derived from pre-F-specific antibodies, and therefore, inducing or boosting NT activity by vaccination will be facilitated by using pre-F antigens that preserve site Ø.
据估计，呼吸道合胞病毒（RSV）在1岁以下婴儿中造成的死亡人数比除疟疾外的任何其他单一病原体都要多，给全球健康带来了沉重负担。病毒进入是由I型融合糖蛋白（F）介导的，该蛋白从亚稳态的前融合（pre-F）三聚体转变为稳定的后融合（post-F）三聚体。一个高度中和敏感的表位，抗原位点Ø，仅在前融合蛋白上发现。我们确定了7至93岁健康受试者血清中中和（NT）活性的哪一部分依赖于针对抗原位点Ø或F上其他抗原位点的特异性抗体。用稳定的前融合蛋白吸附个体血清可去除>90%的中和活性，并耗尽对两种F构象的结合抗体。相比之下，用后融合蛋白吸附可去除约30%的中和活性，并且保留了对前融合蛋白的结合抗体。所有年龄组的这些结果都是一致的。用前融合蛋白突变体进行的蛋白质竞争中和试验，其中位点Ø或II被改变以敲除抗体与相应位点的结合，结果表明这些位点分别占中和活性的约35%和<10%。用单克隆抗体（mAb）进行的结合竞争试验表明，位点Ø特异性抗体的量与中和活性相关，而位点II单克隆抗体竞争结合的程度与中和作用无关。我们的结果表明，人血清中的RSV中和活性主要来自前融合蛋白特异性抗体，因此，使用保留位点Ø的前融合蛋白抗原将有助于通过疫苗接种诱导或增强中和活性。
