HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa.
Retrovirology. 2019 Nov 8;16(1):31. doi: 10.1186/s12977-019-0493-y.
The existing repertoire of HIV-1 patient derived broadly neutralising antibodies (bNAbs) that target the HIV-1 envelope glycoprotein (Env) present numerous and exciting opportunities for immune-based therapeutic and preventative strategies against HIV-1. Combination antibody therapy is required to ensure greater neutralization coverage and limit Env mediated escape mutations following treatment pressure. Engineered bispecific bNAbs (bibNAbs) assimilate the advantages of combination therapy into a single antibody molecule with several configurations reporting potency enhancement as a result of the increased avidity and simultaneous engagement of targeted epitopes. We report the engineering of a novel bibNAb (iMab-CAP256) comprising the highly potent, CAP256.VRC26.25 bNAb with anticipated extension in neutralization coverage through pairing with the host directed, anti-CD4 antibody, ibalizumab (iMab). Recombinant expression of parental monoclonal antibodies and the iMab-CAP256 bibNAb was performed in HEK293T (Human embryonic kidney 293 T antigen) cells, purified to homogeneity by Protein-A affinity chromatography followed by size exclusion chromatography. Antibody assembly and binding functionality of Fab moieties was confirmed by SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis) and ELISA, respectively. Breadth and potency were evaluated against a geographical diverse HIV-1 pseudovirus panel (n = 20). Overall, iMab-CAP256 demonstrated an expanded neutralizing coverage, neutralizing single, parental antibody resistant pseudovirus strains and an enhanced neutralization potency against all dual sensitive strains (average fold increase over the more potent parental antibody of 11.4 (range 2 to 31.8). Potency enhancement was not observed for the parental antibody combination treatment (iMab + CAP256) suggesting the presence of a synergistic relationship between the CAP256 and iMab paratope combination in this bibNAb configuration. In addition, iMab-CAP256 bibNAbs exhibited comparable efficacy to other bibNAbs PG9-iMab and 10E08-iMab previously reported in the literature. The enhanced neutralization coverage and potency of iMAb-CAP256 over the parental bNAbs should facilitate superior clinical performance as a therapeutic or preventative strategy against HIV-1.
现有的 HIV-1 患者来源的广泛中和抗体（bNAb） repertoire 针对 HIV-1 包膜糖蛋白（Env），为基于免疫的 HIV-1 治疗和预防策略提供了许多令人兴奋的机会。需要联合抗体治疗以确保更大的中和覆盖范围，并限制治疗压力后 Env 介导的逃逸突变。工程双特异性 bNAb（bibNAb）将联合治疗的优势整合到单个抗体分子中，几种构型报告由于靶向表位的亲和力和同时结合增强而导致效力增强。我们报告了一种新型 bibNAb（iMab-CAP256）的工程设计，该抗体由高度有效的 CAP256.VRC26.25 bNAb 组成，并通过与宿主定向的抗 CD4 抗体ibalizumab（iMab）配对，预计会扩大中和覆盖范围。亲本单克隆抗体和 iMab-CAP256 bibNAb 的重组表达在 HEK293T（人胚肾 293 T 抗原）细胞中进行，通过 Protein-A 亲和层析后进行纯度均一化，然后进行尺寸排阻层析。通过 SDS-PAGE（十二烷基硫酸钠聚丙烯酰胺凝胶电泳）和 ELISA 分别确认 Fab 片段的抗体组装和结合功能。针对地理多样化的 HIV-1 假病毒组（n=20）评估了广度和效力。总体而言，iMab-CAP256 表现出扩展的中和覆盖范围，可中和单一、亲本抗体耐药的假病毒株，并增强对所有双敏感株的中和效力（相对于更有效的亲本抗体的平均 fold increase 为 11.4（范围为 2 至 31.8）。未观察到亲本抗体联合治疗（iMab+CAP256）的效力增强，这表明在这种 bibNAb 构型中，CAP256 和 iMab 配对位的组合存在协同关系。此外，iMab-CAP256 bibNAb 与文献中先前报道的其他 bibNAb PG9-iMab 和 10E08-iMab 具有相当的疗效。iMAb-CAP256 相对于亲本 bNAb 的增强中和覆盖范围和效力应促进其作为治疗或预防 HIV-1 的策略的优越临床性能。
