Quantification of HPV-16 and HPV-18 Neutralizing Antibodies via a Magnetic Bead-Based Competitive Chemiluminescence Platform.

Persistent infection with high-risk human papillomavirus (HPV) types 16 and 18 is the primary cause of cervical cancer, and vaccination is an effective prevention method. The assessment of vaccine efficacy relies on measuring neutralizing antibodies (nAbs). However, the pseudovirion-based neutralization assay (PBNA), which is widely used as a reference method has limitations such as low throughput and technical complexity. To address this issue, we have developed a rapid and accurate magnetic bead-based competitive chemiluminescence immunoassay (CLIA) for the separate quantitative assessment of HPV-16 and HPV-18 nAbs. This platform uses two assay configurations: HPV-16 detection involves monoclonal antibody (mAb)-coated beads and acridinium ester (AE)-labeled antigens (Ags), while HPV-18 detection involves Ag-coated beads and AE-labeled mAbs. This assay works by measuring the competitive inhibition of tracer binding by sample Abs, resulting in a chemiluminescence signal that is inversely proportional to nAbs concentration. The method has shown acceptable analytical performance, with strong linearity (R² > 0.999) and recovery values within the predefined acceptance range for both assays. A preliminary comparison using 40 serum samples from vaccinated participants showed 97.5% agreement and a strong correlation (R² > 0.95) with PBNA. The selected analytical parameters remained generally comparable after short-term thermal stress at 37 °C for 7 days. These findings support the analytical feasibility of the platform and its further evaluation in HPV vaccine immunogenicity studies and serological monitoring.