PDF(Pubmed)
Abstract：
Efforts to develop an HIV-1 vaccine include those focusing on conserved structural elements as the target of broadly neutralizing monoclonal antibodies. MAb D5 binds to a highly conserved hydrophobic pocket on the gp41 N-heptad repeat (NHR) coiled coil and neutralizes through prevention of viral fusion and entry. Assessment of 17-mer and 36-mer NHR peptides presenting the D5 epitope in rodent immunogenicity studies showed that the longer peptide elicited higher titers of neutralizing antibodies, suggesting that neutralizing epitopes outside of the D5 pocket may exist. Although the magnitude and breadth of neutralization elicited by NHR-targeting antigens are lower than that observed for antibodies directed to other epitopes on the envelope glycoprotein complex, it has been shown that NHR-directed antibodies are potentiated in TZM-bl cells containing the FcγRI receptor. Herein, we report the design and evaluation of covalently stabilized trimeric 51-mer peptides encompassing the complete gp41 NHR. We demonstrate that these peptide trimers function as effective antiviral entry inhibitors and retain the ability to present the D5 epitope. We further demonstrate in rodent and nonhuman primate immunization studies that our 51-mer constructs elicit a broader repertoire of neutralizing antibody and improved cross-clade neutralization of primary HIV-1 isolates relative to 17-mer and 36-mer NHR peptides in A3R5 and FcγR1-enhanced TZM-bl assays. These results demonstrate that sensitive neutralization assays can be used for structural enhancement of moderately potent neutralizing epitopes. Finally, we present expanded trimeric peptide designs which include unique low-molecular-weight scaffolds that provide versatility in our immunogen presentation strategy.
摘要：
开发HIV-1疫苗的努力包括专注于保守结构元件作为广泛中和单克隆抗体的靶标的努力。MAbD5与gp41N-七肽重复(NHR)卷曲螺旋上的高度保守的疏水口袋结合,并通过防止病毒融合和进入而中和。在啮齿动物免疫原性研究中，对呈现D5表位的17聚体和36聚体NHR肽的评估表明，较长的肽引起较高滴度的中和抗体，表明D5口袋外的中和表位可能存在。尽管NHR靶向抗原引起的中和程度和广度低于针对包膜糖蛋白复合物上其他表位的抗体所观察到的程度和广度，已经显示,NHR定向抗体在含有FcγRI受体的TZM-bl细胞中增强。在这里，我们报告了包含完整gp41NHR的共价稳定的三聚体51-mer肽的设计和评估。我们证明了这些肽三聚体作为有效的抗病毒进入抑制剂起作用并保留呈递D5表位的能力。我们在啮齿动物和非人类灵长类动物免疫研究中进一步证明，我们的51聚体构建体相对于A3R5和FcγR1增强的TZM-bl分析中的17聚体和36聚体NHR肽，引发了更广泛的中和抗体库，并改善了初级HIV-1分离株的交叉分化中和。这些结果表明,灵敏的中和测定可用于中等有效中和表位的结构增强。最后,我们介绍了扩展的三聚体肽设计,其中包括独特的低分子量支架,这些支架在我们的免疫原呈递策略中提供了多功能性.
