Zhang Yueru, Mariz Filipe Colaco, Sehr Peter, Spagnoli Gloria, Koenig Karl Moritz, Çelikyürekli Simay, Kreuziger Tim, Zhao Xueer, Bolchi Angelo, Ottonello Simone, Müller Martin
German Cancer Research Center, Im Neuenheimer Feld 242, 69120, Heidelberg, Germany.
EMBL-DKFZ Chemical Biology Core Facility, European Molecular Biology Laboratory, 69117, Heidelberg, Germany.
NPJ Vaccines. 2024 Feb 24;9(1):44. doi: 10.1038/s41541-024-00832-0.
The human papillomavirus minor capsid protein L2 is being extensively explored in pre-clinical studies as an attractive vaccine antigen capable of inducing broad-spectrum prophylactic antibody responses. Recently, we have developed two HPV vaccine antigens - PANHPVAX and CUT-PANHPVAX- both based on heptameric nanoparticle antigens displaying polytopes of the L2 major cross-neutralizing epitopes of eight mucosal and twelve cutaneous HPV types, respectively. Prompted by the variable neutralizing antibody responses against some of the HPV types targeted by the antigens observed in previous studies, here we investigated the influence on immunogenicity of six distinct glycine-proline spacers inserted upstream to a specific L2 epitope. We show that spacer variants differentially influence antigen immunogenicity in a mouse model, with the antigen constructs M8merV6 and C12merV6 displaying a superior ability in the induction of neutralizing antibodies as determined by pseudovirus-based neutralization assays (PBNAs). L2-peptide enzyme-linked immunosorbent assay (ELISA) assessments determined the total anti-L2 antibody level for each antigen variant, showing for the majority of sera a correlation with their repective neutralizing antibody level. Surface Plasmon Resonance revealed that L2 epitope-specific, neutralizing monoclonal antibodies (mAbs) display distinct avidities to different antigen spacer variants. Furthermore, mAb affinity toward individual spacer variants was well correlated with their neutralizing antibody induction capacity, indicating that the mAb affinity assay predicts L2-based antigen immunogenicity. These observations provide insights on the development and optimization of L2-based HPV vaccines.
人乳头瘤病毒次要衣壳蛋白L2作为一种能够诱导广谱预防性抗体反应的有吸引力的疫苗抗原，正在临床前研究中得到广泛探索。最近，我们开发了两种HPV疫苗抗原——PANHPVAX和CUT-PANHPVAX，它们均基于七聚体纳米颗粒抗原，分别展示了8种黏膜型和12种皮肤型HPV的L2主要交叉中和表位的多表位。受先前研究中观察到的针对抗原所靶向的某些HPV类型的中和抗体反应的变异性所推动，我们在此研究了插入特定L2表位上游的6种不同甘氨酸-脯氨酸间隔区对免疫原性的影响。我们表明，间隔区变体在小鼠模型中对抗原免疫原性有不同影响，通过基于假病毒的中和试验（PBNAs）测定，抗原构建体M8merV6和C12merV6在诱导中和抗体方面表现出卓越能力。L2肽酶联免疫吸附测定（ELISA）评估确定了每种抗原变体的总抗L2抗体水平，表明大多数血清的该水平与其各自的中和抗体水平相关。表面等离子体共振显示，L2表位特异性中和单克隆抗体（mAb）对不同抗原间隔区变体表现出不同的亲和力。此外，mAb对各个间隔区变体的亲和力与其诱导中和抗体的能力高度相关，表明mAb亲和力测定可预测基于L2的抗原免疫原性。这些观察结果为基于L2的HPV疫苗的开发和优化提供了见解。
