Targeting neutralizing antibody-defined sites on HIV gp41 for vaccine design

描述（由申请方提供）：HIV-1 gp 41含有高度保守的区域，是疫苗设计的有吸引力的靶点。一个这样的区域是gp 41的膜近端外部区域（MPER），并且与其结合的人单克隆抗体（mAb）2F 5、4 E10和Z13中和来自不同进化枝的HIV-1的初级分离物。此外，gp 41的N-七肽重复（NHR）区域是融合抑制剂药物和中和mAb的靶标。(In在我们的初步研究中，我们已经鉴定了Z13（Z13 e1）的亲和力改进形式，以及针对gp 41的NHR区域引发的兔mAb和人HIV-1中和mAb。 部分由于gp 41结构的异质性以及对HIV-1 gp 41上中和表位的特异性结构和呈递的理解不足，很难诱导出针对gp 41的广泛中和Ab。我们设计了一系列gp 41模拟物，其特异性地呈现gp 41的MPER和NHR区域的中和表位。将这些gp 41模拟物用于免疫家兔，并测量血清中和Ab滴度以确定最佳MPER和NHR先导免疫原（目的1）。为了获得关于中和表位的免疫原性的更具体的知识，将通过噬菌体展示拯救针对这些表位引发的兔mAb，并单独测试中和活性（目的2）。mAb组将用于探测gp 41模拟物，然后引入修饰，以便有利地显示中和表位并封闭非中和表位（目的3）。此外，在一项合作努力中，将确定mAb Z13 e1和两种针对NHR区域（兔和人）的HIV-1中和mAb的结构（目标4）。通过这些方式，将精确评估抗体对gp 41的MPER和NHR区域的接近，这反过来将导致改进的基于gp 41的免疫原，其将引发针对HIV-1的更有效的中和Ab。

DESCRIPTION (provided by applicant): HIV-1 gp41 contains highly conserved regions that are attractive targets for vaccine design. One such region is the membrane-proximal external region (MPER) of gp41, and the human monoclonal antibodies (mAbs) that bind to it, 2F5, 4E10 and Z13, neutralize primary isolates of HIV-1 from different clades. In addition, the N-heptad repeat (NHR) region of gp41 is a target of fusion inhibitor drugs and neutralizing mAbs. (In our preliminary studies, we have identified an affinity-improved version of Z13 (Z13e1), as well as rabbit mAbs and a human HIV-1 neutralizing mAb that were elicited against the NHR region of gp41.) Eliciting broadly neutralizing Abs against gp41 has been difficult due in part to heterogeneity in gp41 structure and a poor understanding of the specific structure and presentation of the neutralizing epitopes on HIV-1 gp41. We have designed a series of gp41 mimetics that specifically present the neutralizing epitopes of the MPER and NHR region of gp41. These gp41 mimetics will be used to immunize rabbits, and the serum neutralizing Ab titers measured to determine the best MPER and NHR lead immunogens (Aim 1). In order to gain more specific knowledge about the immunogenicity of the neutralizing epitopes, rabbit mAbs that were elicited to these epitopes will be rescued by phage display and tested individually for neutralizing activity (Aim 2). The mAb panels will be used to probe the gp41 mimetics, and then modifications will be introduced so as to favorably display the neutralizing epitopes and occlude the non-neutralizing ones (Aim 3). In addition, in a collaborative effort, structures of the mAb Z13e1 and two HIV-1 neutralizing mAbs against the NHR region (rabbit and human) will be determined (Aim 4). In these ways, antibody access to the MPER and NHR region of gp41 will be precisely evaluated, which in turn should lead to improved gp41-based immunogens that will elicit more potent neutralizing Abs against HIV-1.