HUMAN ANTIBODIES TO INTACT VIRIONS FOR VACCINE RESEARCH

描述（由研究者提供）：由于HIV-1包膜在天然病毒体上表达的固有结构特性，广泛有效的HIV-1疫苗的开发受到限制。HIV-1感染涉及env抗原结构和表位呈递的一系列逐步变化，在此期间，病毒展开并暴露与靶细胞表面结构非常接近的中和表位。我们提出，免疫系统很难以更高阶的整合反应，其中两步抗体反应可以修饰包膜以暴露并随后二次识别暴露的中和表位。这种更高的整合必须通过疫苗设计施加于免疫系统，因为免疫原必须被设计成诱导多种类型的抗体，这些抗体通过“暴露”和“中和”这两个步骤的整合一起介导病毒中和。“体液免疫反应的分析受到蛋白质亚基和抗体测定不能准确反映天然病毒体上复杂的寡聚体结构的事实的阻碍。为了解决这些问题，鉴定与天然原代分离株病毒粒子反应的抗体，并促进抗体特异性和病毒中和的分析，我们设计了一种使用来自HIV-1原代分离株的完整病毒粒子的测定法。当检测来自HIV-1感染个体的血清中与完整的原代分离病毒粒子反应的IgG抗体时，36%的HIV-1感染个体捕获病毒（> 300 pg/ml）。只有7%的人捕获了大量的病毒（> 500 pg/ml）。相比之下，F240，一种gp 41人单克隆抗体（HMAb）捕获超过2150 pg/ml的p24。显然，与原代分离病毒体反应的抗体在大多数HIV-1感染个体中并不普遍，这可能与血清一般不能中和原代分离物有关。我们建议产生与进化枝A-G的完整原代分离株结合的HMAb，以鉴定广泛反应性抗体。我们进一步提出在反应性抗体结合后产生针对暴露在病毒体上的表位的抗体。从原代分离物中分离和鉴定与完整病毒体反应的HMAb，应能鉴定出用于疫苗目的的抗原表位和基序。

DESCRIPTION (as provided by investigator): Development of a broadly effective HIV-1 vaccine has been limited because of the inherent structural properties the HIV-1 envelope expressed on the native virion. HIV-1 infection involves a series of stepwise changes in env antigenic structures and epitope presentation during which the virus unfolds and exposes neutralizing epitopes in close proximity to the target cell surface structure. We propose, that it is difficult for the immune system to respond in a higher order integration in which a two step antibody response can modify the envelope to expose and then secondarily recognize exposed neutralizing epitopes. This higher integration must be imposed on the immune system through vaccine design in that immunogens must be designed to induce multiple classes of antibodies which together mediate viral neutralization through an integration of these two steps: "exposure" and "neutralization." Analysis of the humoral immune response has been hampered by the fact that protein subunits and antibody assays do not accurately reflect the complex oligomeric structure on native virions. To address these concerns, identify antibodies that react with native primary isolate virions, and facilitate analysis of antibody specificity and viral neutralization, we have designed an assay using whole virions from primary isolates of HIV-1. When serum from HIV-1 infected individuals was tested for IgG antibodies reactive with intact primary isolate virions, 36% of HIV-1 infected individuals captured virus (>300pg/ml). Only 7% of these individuals captured significant quantities of virus (>500pg/ml). By comparison, F240, a gp41 human monoclonal antibody (HMAb) captured more than 2150pg/ml of p24. Clearly antibodies reactive with primary isolate virions are not prevalent in the majority of HIV-1 infected individuals which may be related to the general inability of sera to neutralize primary isolates. We propose to generate HMAb which bind to intact primary isolates of clades A-G to identify broadly reactive antibodies. We further propose to generate antibodies to epitopes exposed on virions following binding of reactive antibodies. Isolation and characterization of HMAb reactive with intact virions from primary isolates should lead to the identification of antigenic epitopes and motifs for vaccine purposes.