National Institute of Diagnostics and Vaccine Development in Infectious Diseases, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China; School of Life Science, Xiamen University, Xiamen, China.
National Institute of Diagnostics and Vaccine Development in Infectious Diseases, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China.
Eur J Pharm Biopharm. 2019 Aug;141:221-231. doi: 10.1016/j.ejpb.2019.05.027. Epub 2019 May 30.
Thimerosal has been widely used as a preservative in human vaccines for decades. Thimerosal, a thiol capping agent with ethyl mercury being the active degradant, could have impacts on the vaccine potency due to potential thiol modification. The effects on the antigenicity and immunogenicity of human papillomavirus (HPV) virus-like particles (VLPs) in the presence of thimerosal was studied. In general, reduced binding activity was observed between HPV antigens and monoclonal antibodies (mAbs) upon thimerosal treatment, accompanied by reduced protein conformational stability. The immunogenicity of a pentavalent vaccine formulation (HPV6, HPV11, HPV16, HPV18 and hepatitis E virus) with or without thimerosal was studied in mice. The functional antibody titres, as well as the binding titres, were determined, showing a substantial decrease for vaccine formulations containing thimerosal for HPV16/18. Similarly, epitope-specific competition assays using specific and functional mAbs as tracers also showed a significant reduction in immunogenicity for HPV16/18 in the presence of thimerosal. Structural alterations in the capsid protein for HPV18 were observed with cryo-electron microscopy and 3-dimensional reconstruction in the comparative structural analysis. The results should alert scientists in formulation development field on the choice for vaccine preservatives, in particular for thiol-containing antigens.
硫柳汞作为一种含硫的封端剂，乙基汞是其活性降解产物，几十年来一直被广泛用作人类疫苗的防腐剂。由于潜在的巯基修饰，硫柳汞可能会影响疫苗的效力。本研究考察了硫柳汞对人乳头瘤病毒（HPV）病毒样颗粒（VLPs）的抗原性和免疫原性的影响。一般来说，硫柳汞处理后，HPV 抗原与单克隆抗体（mAb）之间的结合活性降低，同时蛋白构象稳定性降低。在小鼠中研究了含有或不含有硫柳汞的五价疫苗制剂（HPV6、HPV11、HPV16、HPV18 和戊型肝炎病毒）的免疫原性。测定了功能性抗体效价和结合效价，结果表明含硫柳汞的 HPV16/18 疫苗制剂的效价显著降低。同样，使用特异性和功能性 mAb 作为示踪剂的表位特异性竞争分析也表明，硫柳汞存在时 HPV16/18 的免疫原性显著降低。在比较结构分析中，通过冷冻电子显微镜和 3 维重建观察到 HPV18 衣壳蛋白的结构改变。这些结果应该提醒制剂开发领域的科学家在选择疫苗防腐剂时要注意，特别是对于含巯基的抗原。
