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统计，全世界约有3600万人感染了艾滋病毒-1 2015年底，110万人死于这种疾病。接种疫苗最 预防传染病的有效策略，成功的疫苗通常具有保护性，因为它们 引发中和病原体的抗体（1）。虽然目前还没有针对HIV-1的保护性疫苗，但广泛而言， 从感染患者分离的中和抗体（bNAb）在动物感染模型中具有保护性， 浓度相对较低。这些抗体是有效的中和剂，其识别免疫球蛋白的保守特征。 病毒包膜刺突（Env），其在不同的病毒株之间共享，并且普遍认为， 一种疫苗，eliminabNAbs将保护免受HIV-1感染。然而，除了美洲驼， 和基因工程小鼠中，bNAb没有被疫苗接种所诱发（2）。在基因方面的实验 基因敲入小鼠表明，bNAb的发育需要生殖系靶向Env抗原， 专门设计用于激活表达对应于bNAb的种系前体抗体的B细胞 （3-5）。此外，单一抗原是不够的，bNAb的发展需要一个特定的序列， 按顺序递送的免疫原（5-8）。然而，在基因敲入小鼠中设计的免疫方案不能 部分是因为缺乏对野生型（WT）小鼠或其它动物之间关系的理解， 生殖系抗原亲和力和bNA B前体B细胞频率之间的关系 在竞争性多克隆B细胞存在下的反应。本研究的主要目的是：1.定义 前体B细胞频率和对同源抗原亲和力在募集bNA B中的精确关系 前体进入生发中心; 2.测试的想法，使用抗独特型的特定前体的预扩增 抗体将促进抗CD 4 b抗体的发展。亲和力和 前体B细胞频率将在采用Dr. 斯塔马塔托斯和迈奎尔使用抗独特型抗体扩增bNAb的新疫苗接种方法 将在三种不同的小鼠模型中检测疫苗接种前的前体频率， 多克隆性：I）在仅HC敲入小鼠中，由于可变的小鼠光，其具有最低水平的多克隆性 链II）将表达单一Env特异性BCR的可变数目的敲入B细胞过继转移至野生型 小鼠和III）表达人生殖系IG基因的完全多克隆小鼠。这些机构获得的信息 实验将促进我们对如何解决如何开发保护性药物的问题的理解。 HIV-1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.