Quantitative Detection of Hepatitis B Virus Particles via Dual-Targeting HBsAg and Nucleic Acid with Immunomolecular Assay.

SARS-CoV-2, HBV, and other viral pathogens represent significant public health threats. While viral replication produces numerous subviral particles, only intact viral particles are infectious, making them essential biomarkers for assessing viral infection and replication. Current diagnostic methods primarily detect antigens or nucleic acids, but they do not accurately reflect the virus's infectious potential. Techniques such as plaque assays, electrochemical biosensors, and size exclusion chromatography (SEC) are limited by operational complexity and quantification precision. In this study, we present a novel quantitative assay for detecting HBV particles, utilizing a dual-target immune molecular approach to simultaneously quantify HBsAg and viral nucleic acids. PreS1 antibodies selectively enrich viral surface particles, followed by viral genome amplification for precise quantification. This method is also applicable to HBV core particles. The assay demonstrated high specificity, sensitivity, and stability, meeting clinical reagent standards. Analysis of serum samples from 220 chronic hepatitis B (CHB) patients revealed a weak correlation between serum DNA levels of particle types and traditional biomarkers (HBsAg, HBcrAg, and total HBV DNA), indicating that intact viral particles could serve as novel biomarkers for clinical infection management. Furthermore, CHB patients treated with nucleotide analogs exhibited higher baseline levels of complete viral particles and faster clearance kinetics compared to core particles. This immune molecular assay offers reliable quantification of other intact viral particles, providing a valuable tool for assessing viral activity and holding significant potential for clinical viral diagnosis.