title: Quantitative and epitope-specific antigenicity analysis of the human papillomavirus 6 capsid protein in aqueous solution or when adsorbed on particulate adjuvants.
abstract: Human papillomavirus (HPV) 6 is a human pathogen which causes genital warts. Recombinant virus-like particle (VLP) based antigens are the active components in prophylactic vaccines to elicit functional antibodies. The binding and functional characteristics of a panel of 15 murine monoclonal antibodies (mAbs) against HPV6 was quantitatively assessed. Elite conformational indicators, recognizing the conformational epitopes, are also elite viral neutralizers as demonstrated with their viral neutralization efficiency (5 mAbs with neutralization titer below 4ng/mL) in a pseudovirion (PsV)-based system. The functionality of a given mAb is closely related to the nature of the corresponding epitope, rather than the apparent binding affinity to antigen. The epitope-specific antigenicity assays can be used to assess the binding activity of PsV or VLP preparations to neutralizing mAbs. These mAb-based assays can be used for process monitoring and for product release and characterization to confirm the existence of functional epitopes in purified antigen preparations. Due to the particulate nature of the alum adjuvants, the vaccine antigen adsorbed on adjuvants was considered largely as "a black box" due to the difficulty in analysis and visualization. Here, a novel method with fluorescence-based high content imaging for visualization and quantitating the immunoreactivity of adjuvant-adsorbed VLPs with neutralizing mAbs was developed, in which antigen desorption was not needed. The facile and quantitative in situ antigenicity analysis was amendable for automation. The integrity of a given epitope or two non-overlapping epitopes on the recombinant VLPs in their adjuvanted form can be assessed in a quantitative manner for cross-lot or cross-product comparative analysis with minimal manipulation of samples.
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: km123ll@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: wxinc35@163.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: 471640173@qq.com.
authors.forename: Lu
authors.initials: L
authors.lastname: Cao
authors.affiliation: Innovax Corporation, Xiamen, Fujian 361000, PR China. Electronic address: good_lin@innovax.cn.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Innovax Corporation, Xiamen, Fujian 361000, PR China. Electronic address: minxi.wei@innovax.cn.
authors.forename: Minxi
authors.initials: M
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China; School of Life Science, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: mjfang@xmu.edu.cn.
authors.forename: Mujin
authors.initials: M
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China; School of Life Science, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: shaowei@xmu.edu.cn.
authors.forename: Shaowei
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China; School of Life Science, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: zhangj@xmu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China; School of Life Science, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: nsxia@xmu.edu.cn.
authors.forename: Ningshao
authors.initials: N
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, PR China; School of Public Health, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: qinjian_zhao@xmu.edu.cn.
authors.forename: Qinjian
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D000327:Adsorption; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology*; D036022:Capsid Proteins / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D052163:Human papillomavirus 6; D051379:Mice; D011994:Recombinant Proteins / Q000276:immunology; D064166:Vaccine Potency; D058425:Vaccines, Virus-Like Particle / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D036022:Capsid Proteins; D000939:Epitopes; D011994:Recombinant Proteins; D058425:Vaccines, Virus-Like Particle
keywords: Conformational sensitivity; Human papillomavirus; In situ antigenicity analysis; Monoclonal antibody; Neutralization epitope; Pseudovirion