Screening and identification of B cell epitope within the major capsid protein L1 of HPV 52, using monoclonal antibodies

The L1 protein of Human papillomavirus (HPV), the main capsid protein, induces the formation of neutralizing antibodies. In this study, HPV52 L1 protein was induced to be expressed. Monoclonal antibody (mAb) 6A7 against L1 protein were screened by cell fusion techniques. Western Blot and immunofluorescence assay (IFA) demonstrated the specificity of the mAb. The L1 protein was truncated for prokaryotic expression (N1~N7) and Dot-ELISA showed that 6A7 recognized N3 (aa 200~350). The immunodominant regions were truncated again for expression, with 6A7 recognizing N6 (aa 251~305). The N6 proteins were further truncated and then were constructed an four-segment eukaryotic expression vector. IFA showed that 6A7 could recognize amino acid 262~279. Amino acid 262~279 was selected to be truncated into short peptides P1 and P2. Finally, Peptide-ELISA and Dot-ELISA showed that the epitope regions of mAb 6A7 were amino acid 262~273. The mAbs with defined epitopes can lay the foundation for the analysis of antigenic epitope characteristics and promote the development of epitope peptide vaccines.