Activation of HIV-1 specific B cell precursors using novel vaccine approaches

项目摘要 根据世界卫生组织的数据，全球约有3600万人携带艾滋病毒-1 2015年底，有110万人在同一年死于这种疾病。接种疫苗是最 预防传染病的有效策略，而成功的疫苗通常具有保护性，因为它们 诱导中和病原体的抗体(1)。尽管目前还没有针对HIV-1的保护性疫苗，但总的来说 从感染患者中分离的中和抗体(BNAbs)在动物感染模型中甚至具有保护作用 在相对较低的浓度下。这些抗体是有效的中和剂，可以识别保守的特征 在不同病毒株之间共享的病毒包膜尖峰(Env)，人们普遍认为 一种能产生bNAbs的疫苗将对HIV-1感染具有保护作用。然而，除了大羊驼， 和基因工程小鼠，接种疫苗还没有诱导出bNAbs(2)。基因工程中的实验 转基因小鼠表明，bNAb的发展需要种系靶向的环境抗原，这些抗原是 专门设计用来激活表达与bNAbs相对应的生殖系前体抗体的B细胞 (3-5)。此外，单一的抗原是不够的，而bNAb的发展需要一系列特定的 免疫原按顺序递送(5-8个)。然而，在转基因小鼠身上设计的免疫方案却不能 推广到野生型(Wt)小鼠或其他动物，部分原因是对两者之间的关系缺乏了解 生殖系抗原亲和力和bNAb前体B细胞频率在启动生产性免疫中的作用 在竞争的多克隆B细胞存在时的反应。拟议研究的目标是：1.界定 募集bNAb时前体B细胞频率与同源抗原亲和力的精确关系 前体进入生发中心；2.检验使用抗独特型预扩张特定前体的想法 抗体将促进抗CD4b抗体的发展。亲和力与亲和力的关系 前体B细胞频率将在过继转移实验中使用Dr。 斯塔马托斯和麦奎尔。使用抗独特型抗体扩大bNAb的新疫苗接种方法 接种前的前体频率将在三种不同水平的小鼠模型中进行测试 多克隆性：i)仅在HC中，由于可变的鼠光，具有最低水平多克隆性的敲入小鼠 Chains II)将表达单个环境特异性BCR的数量可变的敲入B细胞过继转移到wt 小鼠和iii)表达人类生殖系Ig基因的完全多克隆小鼠。通过这些机构获得的信息 实验将增进我们对如何处理如何开发保护的问题的理解 针对HIV-1的疫苗。

Project Summary According to the World Health Organization, approximately 36 million people worldwide were living with HIV-1 at the end of 2015 and 1.1 million people died from this disease during the same year. Vaccination is the most effective strategy to prevent infectious diseases, and successful vaccines are usually protective because they elicit antibodies that neutralize the pathogen (1). Although there is no protective vaccine against HIV-1, broadly neutralizing antibodies (bNAbs) isolated from infected patients are protective in animal models of infection even at relatively low concentrations. These antibodies are potent neutralizers that recognize conserved features of the virus envelope spike (Env) that are shared among diverse strains of the virus, and it is generally agreed that a vaccine that elicits bNAbs would be protective against HIV-1 infection. However, with the exception of llamas and genetically engineered mice, bNAbs have not been elicited by vaccination (2). The experiments in genetically engineered knock-in mice showed that bNAb development required germline-targeting Env-antigens that were specifically designed to activate B cells expressing the germline precursor antibodies that correspond to bNAbs (3-5). In addition, singular antigens were not sufficient, and bNAb development required a sequence of specific immunogens delivered in order (5-8). However, the immunization schemes devised in knock-in mice could not be extended to wild type (wt) mice or other animals in part because of lack of understanding of the relationship between germline antigen affinity and bNAb precursor B cell frequency in initiating a productive immune response in the presence of competing polyclonal B cells. The objects of the proposed research are to: 1. define the precise relationship between precursor B cell frequency and affinity to cognate antigen, in recruiting bNAb precursors into the germinal center; 2. test the idea that pre-expansion of specific precursors using anti-idiotypic antibodies will facilitate the development of anti-CD4bs antibodies. The relationship between affinity and precursor B cell frequency will be defined in adoptive transfer experiments using antigens provided by Drs. Stamatatos and McGuire. New vaccination approaches using anti-idiotypic antibodies to expand bNAb precursor frequency before vaccination will be tested in three different mouse models with variable levels of polyclonality: I) In HC only knock-in mice which have the lowest level of polyclonality due to variable mouse light chains II) adoptive transfer of variable numbers of knock-in B cells expressing a single Env-specific BCR into wt mice and III) fully polyclonal mice expressing human germline Ig genes. The information obtained by these experiments will advance our understanding of how to approach the problem of how to develop a protective vaccine against HIV-1.