Arming Neutrophils for the Destruction of HIV by Anti-HIV Antibody

描述（由申请方提供）：尽管感染后对HIV产生了强烈的抗体应答，但中和抗体应答较差且在控制疾病方面无效;然而，在非人灵长类动物模型中，特异性抗体已被证明可有效预防感染。因此，新的免疫学方法对于抗体在治疗HIV感染中是有用的是必要的。除了通过抗体直接中和病毒之外，通过将HIV靶向效应细胞，抗体介导的HIV抑制具有更广泛的潜力。我们假设，使用包含选择的抗HIV抗体和抗IgA受体（CD 89）抗体的双特异性抗体将HIV导向嗜中性粒细胞将有效地破坏HIV和HIV感染的细胞。中性粒细胞是最主要的白色血细胞类型，在介导细胞毒性方面非常有效，并且对艾滋病毒感染具有相对抵抗力。因此，如果它们能够被引导和武装以摧毁HIV和受感染的细胞，它们就代表了对抗感染的重要武器库。基于结构-功能关系，我们建议研究使用三种不同的人源抗HIV单克隆抗体产生的双特异性抗体。IgG 1b 12是一种中和抗体，具有独特的结构，使其能够更好地接近病毒的CD 4结合位点。F425 B4 e8也是V3环的有效中和抗体，V3环在病毒和感染细胞上相对容易接近。最后，鉴于gp 41上的高度保守的簇I表位（由抗体F240识别）的暴露，我们还建议确定具有广泛抗HIV反应性的双特异性抗体破坏HIV的能力。F240的使用允许在固有中和活性与嗜中性粒细胞定向杀伤之间的清楚区分。将测试双特异性抗体刺激中性粒细胞效应子功能和破坏HIV的能力。双特异性抗体构建体将被制备为单链Fv（scFv）抗体。然而，由于scFv抗体在体内的短半衰期可能是限制性的，我们还提出产生具有修饰的Fc结构域的构建体。预期部分基于表位暴露，一些构建体将比其他构建体更有效。还将测试构建体对具有结合gp 120的未感染细胞的旁观者杀伤。鉴定在体外抑制病毒产生方面具有活性的构建体，具有最小的旁观者杀伤，将允许在非人灵长类动物感染模型中进行进一步测试。这些研究代表了治疗慢性HIV感染的重要进展。D 公共卫生相关性：尽管与抗逆转录病毒药物的联合治疗取得了成功，但治疗HIV感染还需要额外的治疗手段。由于直接抑制病毒的抗体在体内无效或罕见，我们建议设计抗体将HIV靶向细胞进行破坏。这些研究代表了治疗慢性HIV感染的重要进展。

DESCRIPTION (provided by applicant): Despite a robust antibody response to HIV following infection, the neutralizing antibody response is poor and ineffective at controlling disease; however, specific antibodies have been shown effective at preventing infection in non-human primate models. Thus, novel immunotherapeutic approaches are necessary for antibodies to be useful in treating HIV infection. In addition to the direct neutralization of virus by antibodies, there is a broader potential for antibody mediated inhibition of HIV by targeting HIV to effector cells. We hypothesize that directing HIV, using bispecific antibodies incorporating select anti-HIV antibodies and anti-IgA receptor (CD89) antibody, to neutrophils will effectively destroy HIV and HIV infected cells. Neutrophils, which are the most predominant type of white blood cells, are very efficient at mediating cell cytotoxicity as well as relatively resistant to infection with HIV. Therefore, they represent a significant arsenal against infection if they can be directed and armed to destroy HIV and infected cells. Based on structure-function relationships, we propose to study bispecific antibodies generated using three different human anti-HIV monoclonal antibodies. IgG1b12 is a neutralizing antibody with a unique structure giving it improved access to the CD4 binding site of virus. F425B4e8 is also a potent neutralizing antibody, to the V3 loop, which is relatively accessible on virus and infected cells. Finally, given the exposure of the well-conserved cluster I epitope on gp41, recognized by the antibody F240, we also propose to determine the ability of a bispecific antibody, with broad anti-HIV reactivity, to destroy HIV. The use of F240 allows clear differentiation between inherent neutralization activity from neutrophil directed killing. Bispecific antibodies will be tested for the ability to stimulate neutrophil effector functions and the destruction of HIV. Bispecific antibody constructs will be prepared as single chain Fv (scFv) antibodies. However, since the short half-life of scFv antibodies in vivo may be limiting, we also propose to generate constructs with a modified Fc domain. It is expected that some constructs will be more effective than others based in part on epitope exposure. Constructs will also be tested for bystander killing of uninfected cells with bound gp120. Identification of constructs active in vitro at inhibiting viral production, with minimal bystander killing, will allow for further testing in non-human primate models of infection. These studies represent an important advance in treating chronic HIV infection. D PUBLIC HEALTH RELEVANCE: espite the success of combination therapy with anti-retroviral agents, additional means of therapy are required for the treatment of HIV infection. Since antibodies that directly inhibit virus are either ineffective or rare in vivo, we propose to design antibodies to target HIV to cells for destruction. These studies represent an important advance in treating chronic HIV infection.