Study of intact virus-like particles of human papillomavirus by capillary electrophoresis

Virus-like particles of human papillomavirus (HPV-VLP), resulting from the self-assembly of the capsid proteins (L1 or L1 and L2), have been widely used to study HPV as they are similar to the native virion. Moreover, two prophylactic vaccines, Gardasil® and Cervarix®, are based on HPV-VLP L1. Analytical techniques currently used to characterize HPV-VLP, such as SDS-PAGE, Western blot, ELISA, are time-consuming and semi-quantitative. In this study, capillary electrophoresis (CE) was evaluated for the analysis of intact HPV16-VLP. The usefulness of capillary inner wall coating as well as various BGEs, pH and detergent additives were investigated. Reproducible HPV-VLP analysis in CE was achieved using poly(ethylene oxide) coated capillary and a BGE containing high salt concentration and low SDS concentration. The developed method enables HPV-VLP detection in less than 10 min (migration times RSD : 1.6 %). The identity of HPV-VLP peak was confirmed by comparison with a sample obtained from a wild-type baculovirus and with VLP-based vaccine, Gardasil®, after adjuvant dissolution. Finally, we applied the developed methodology to VLP-based vaccines, demonstrating that CE could be successfully used for vaccine quality control.