Moore Penny L, Gorman Jason, Doria-Rose Nicole A, Morris Lynn
Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.
Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Immunol Rev. 2017 Jan;275(1):217-229. doi: 10.1111/imr.12501.
The development of a preventative HIV vaccine able to elicit broadly neutralizing antibodies (bNAbs) remains a major challenge. Antibodies that recognize the V2 region at the apex of the HIV envelope trimer are among the most common bNAb specificities during chronic infection and many exhibit remarkable breadth and potency. Understanding the developmental pathway of these antibodies has provided insights into their precursors, and the viral strains that engage them, as well as defined how such antibodies mature to acquire breadth. V2-apex bNAbs are derived from rare precursors with long anionic CDR H3s that are often deleted in the B cell repertoire. However, longitudinal studies suggest that once engaged, these precursors contain many of the structural elements required for neutralization, and can rapidly acquire breadth through moderate levels of somatic hypermutation in response to emerging viral variants. These commonalities in the precursors and mechanism of neutralization have enabled the identification of viral strains that show enhanced reactivity for V2 precursors from multiple donors, and may form the basis of germline targeting approaches. In parallel, new structural insights into the HIV trimer, the target of these quaternary antibodies, has created invaluable new opportunities for ontogeny-based immunogens designed to select for rare V2-bNAb precursors, and drive them toward breadth.
开发一种能够引发广泛中和抗体(bNAbs)的预防性HIV疫苗仍然是一项重大挑战。在慢性感染期间,识别HIV包膜三聚体顶端V2区域的抗体是最常见的bNAb特异性之一,许多此类抗体表现出显著的广度和效力。了解这些抗体的发育途径有助于深入了解它们的前体、与之结合的病毒株,以及确定此类抗体如何成熟以获得广度。V2顶端bNAbs源自具有长阴离子互补决定区H3(CDR H3)的罕见前体,这些前体在B细胞库中常常缺失。然而,纵向研究表明,一旦被激活,这些前体就包含许多中和所需的结构元件,并且可以通过适度水平的体细胞超突变快速获得广度,以应对新出现的病毒变体。这些前体和中和机制的共性使得能够鉴定出对来自多个供体的V2前体表现出增强反应性的病毒株,并可能构成种系靶向方法的基础。与此同时,对这些四级抗体的靶标——HIV三聚体的新结构见解,为基于个体发育的免疫原创造了宝贵的新机会,这些免疫原旨在选择罕见的V2 - bNAb前体,并促使它们获得广度。
Cell Host Microbe. 2016-3-9
Proc Natl Acad Sci U S A. 2016-3-8