Slupetzky Katharina, Gambhira Ratish, Culp Timothy D, Shafti-Keramat Saeed, Schellenbacher Christina, Christensen Neil D, Roden Richard B S, Kirnbauer Reinhard
Laboratory of Viral Oncology, Division of Immunology, Allergy and Infectious Diseases, Department of Dermatology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Vaccine. 2007 Mar 1;25(11):2001-10. doi: 10.1016/j.vaccine.2006.11.049. Epub 2006 Nov 29.
Peptides of the papillomavirus L2 minor capsid protein can induce antibodies (Ab) that neutralize a broad range of human papillomavirus (HPV) genotypes. Unfortunately, L2 is antigenically subdominant to L1 in the virus capsid. To induce a strong anti-L2 Ab response with cross-neutralizing activity to other mucosal types, chimeric virus-like particles (VLP) were generated in which HPV16 L2 neutralization epitopes (comprising L2 residues 69-81 or 108-120) are inserted within an immunodominant surface loop (between residues 133 and 134) of the L1 major capsid protein of bovine papillomavirus type 1 (BPV1). These chimeras self-assembled into pentameric capsomers, or complete VLP similar to wild type (wt) L1 protein. Immunization of rabbits with assembled particle preparations induced L2-specific serum Ab with titers 10-fold higher than those induced by cognate synthetic L2 peptides coupled to KLH. Antisera to both chimeric proteins partially neutralized HPV16 pseudovirions, confirming that both HPV16 L2 peptides define neutralization epitopes. When analyzed for the ability to cross-neutralize infection by authentic HPV11 virions, using detection of early viral RNA by RT-PCR-assays as the readout, immune serum to chimeric protein comprising L2 residues 69-81, but not 108-120, was partially neutralizing. In addition, mouse-antiserum induced by vaccinations with synthetic L2 peptide 108-120, but not 69-81, was partially neutralizing in this assay. Induction of cross-neutralization Ab by L2 epitopes displayed on chimeric VLP represents a possible strategy for the generation of broad-spectrum vaccines to protect against relevant mucosal HPV and associated neoplasia.
乳头瘤病毒L2次要衣壳蛋白的肽段能够诱导产生可中和多种人类乳头瘤病毒（HPV）基因型的抗体（Ab）。遗憾的是，在病毒衣壳中，L2在抗原性上低于L1。为了诱导产生对其他黏膜类型具有交叉中和活性的强烈抗L2 Ab反应，构建了嵌合病毒样颗粒（VLP），其中HPV16 L2中和表位（包含L2的69 - 81位残基或108 - 120位残基）插入到1型牛乳头瘤病毒（BPV1）L1主要衣壳蛋白的一个免疫显性表面环（133和134位残基之间）内。这些嵌合体自组装成五聚体衣壳粒，或形成与野生型（wt）L1蛋白相似的完整VLP。用组装好的颗粒制剂免疫兔子，诱导产生的L2特异性血清Ab效价比与钥孔血蓝蛋白（KLH）偶联的同源合成L2肽段诱导产生的效价高10倍。针对两种嵌合蛋白的抗血清均可部分中和HPV16假病毒颗粒，证实这两种HPV16 L2肽段均确定了中和表位。当通过逆转录聚合酶链反应（RT-PCR）检测早期病毒RNA作为读数，分析其对真实HPV11病毒颗粒感染的交叉中和能力时，针对包含L2的69 - 81位残基而非108 - 120位残基的嵌合蛋白的免疫血清具有部分中和作用。此外，在此检测中，用合成L2肽段108 - 120而非69 - 81进行疫苗接种诱导产生的小鼠抗血清也具有部分中和作用。嵌合VLP上展示的L2表位诱导产生交叉中和Ab，这代表了一种可能的策略，用于制备广谱疫苗以预防相关黏膜HPV感染及相关肿瘤形成。
