Research Progress of HPV L1 Capsid Protein in Prediction of Cervical Lesions

Cervical cancer is one of the most common malignant gynecological tumors and has the second highest incidence of all malignancies in females.Chronic and persistent infection with High Risk Human Papillomavirus(HR-HPV)is the main cause of cervical cancer.There is a distinct lack of methodology by which to determine whether cervical epithelial dysplasia is cancerous following HPV infection.HPV L1 capsid protein is a major structural protein of human papillomavirus(HPV),and it is the main target of the local cellular immune response aiming to combat human papillomavirus after HPV infection within cervical cells.Greater understanding of HPV L1 capsid protein and its association with cervical cytology,histopathology,patient age and human papillomavirus viral load has the potential to contribute toward improved the diagnosis and management of cervical cancer,providing useful information for gynecological clinicians in the hope of improving patient treatment and quality of life.This article reviews the predictive utility of HPV L1 capsid protein for cervical lesions.

液基细胞学制片技术与人乳头瘤病毒L1壳蛋白检测对子宫颈病变诊断及进展风险评估

目的：探讨液基细胞学制片技术对诊断子宫颈病变的价值,评价人乳头瘤病毒L1（HPV L1）在子宫颈不同病变脱落细胞中的表达差异及意义。方法：将河北省廊坊市第四人民医院2009年1月~2013年8月1400例妇科门诊就诊妇女纳入研究,对所有入组人员进行液基细胞学（LCT）检查及脱落细胞中HPV L1蛋白的表达检测,同时将宫颈活检病理学结果做为基线进行比较参照。结果：（1）1400例受检妇女中,LCT（＋）30例,占2.1%,HPV L1蛋白检测（＋）18例,占1.29%;LCT及HPV L1蛋白检测均（＋）8例,LCT及HPV L1蛋白检测均（-）1360例。（2）将LCT检测结果呈现（＋）的30例妇女进行病理组织活检,结果呈现（＋）为23例,将HPV L1蛋白检测结果呈现（＋）18例妇女进行病理组织活检,结果呈现（＋）为14例,LCT及HPV L1蛋白检测均（-）1360例中有497例妇女自愿接受病理活检,结果显示1例妇女呈现（＋）,占0.2%。共545例妇女接受病理活检,其中38例呈现（＋）,比例为6.97%;（3）LCT和HPV L1蛋白两种方法联合检测的灵敏度及特异度均高于单一方法的检测（P〈0.05）。结论：液基细胞学联合HPV L1蛋白检测可提高宫颈病变的诊断率,有望作为临床早期筛查宫颈瘤变的有效方法。

Carboxyl Terminus Truncated Human Papillomavirus Type 58 L1 Protein Maintains Its Bioactivity and Ability to Form Virus-like Particles

Summary: To prepare carboxyl terminus truncated human papillomavirus type 58 L1(HPV58L1) protein and evaluate its ability to form virus-like particles, the baculovirus and Sf-9 insect cells was used to express HPV58L1 protein, and pFastBac-Htb containing HPV58L1 gene sequence of carboxyl terminus truncation was generated. Then Sf-9 cells were infected with recombinant baculovirus. After being cultured, the post-infected cells expressing-HPV58L1 protein-were harvested and analyzed by SDS-PAGE and Western blot. The ProBond~TM purification system was used for protein purification. The bio-activity of purified protein was identified by mouse erythrocyte hemagglutination assay, and the VLP formation was examined with transmission electron microscope. Our results showed that the recombinant baculovirus was generated and the Sf-9 cells was infected with the recombinant baculovirus, and after collecting, total cellular proteins were extracted. Truncated HPV58L1 protein with MW 58KD was revealed by SDS-PAGE and confirmed by Western blot. The purified L1 proteins under native condition could cause mouse erythrocytes to agglutinate and form VLP. It is concluded that HPV58L1 protein with carboxyl terminus truncation could be efficiently expressed. In baculovirus Sf-9 cells expression system, the purified protein could self-assemble into virions in vitro, and induce agglutination of mouse erythrocytes, indicating that carboxyl terminus truncation does not interfere with the bioactivity of HPV58L1 protein.

MAPPING EPITOPES OF HUMAN PAPILLOMAVIRUS TYPE 16 L1 PROTEIN WITH A PHAGE DISPLAY EPITOPE LIBRARY

The objective of this study is to map epitopes on HPMAPV16 L1 protein and provide information to the design of HPV16 prophylactic peptide vaccine. The epitopes on L1 protein were screenedby polyclonal and two monoclonal antibodies (BS and F4G3) against RPV16 L1 protin from a 6-merfd phage display epitope library with the method or immuuo-afrinity screening (Biopauuing). Aferthree rounds or Bio-Panning, the Positive phages were detected by L1 antibodies again with ELISA.The positive phages reacted strongly with L1 antibodies were then identified by DNA sequencing.Three mimotopes have been screened by polycloual and two monoclonal antibodies. The mimotope(LSLFSC) reacted with mouoclonal antibody B8 showed 50% pomology with the sequence 270275a. a (DSLFFY) of prototype HPV16 L1. Another mimotope (LTSSYS) reacted with polyclonalantibodies had 66% pomology with the L1 sequence 516~521a. A(TTSSTS), also a mimotope (DRWDRF) was found had the bomologic RF with the known L1 sequence 441 ~446a. a. The mimotopesLSLFSC and DRWDRF were adjacent to the epitopes at 267~269a. a and 422~441 a. a reported byother researchers Previously. Our results suggest that there might be a batch of epitopes on HPV16L1 ppotein, and the predominant epitopes of HPV16 L1 protein are located in the above two domains. These results will be helpful for design or HPV16 prophylactic peatide vaccines and HPVpolyvalent vaccines.