Ex Vivo Fluorescent Labeling of HBV-Specific B Cells in Chronic Hepatitis B Patients

Fluorescently conjugated antigen-bait systems have been extensively used to identify antigen-specific B cells and probe humoral immunity across different settings. Following this approach, we used HBV antigens to bind the B cell receptor (BCR), permitting antigen-specific B cell detection by flow cytometry. Fluorochromes can either be attached covalently via chemical conjugation to the antigen or attached non-covalently by biotinylating the antigen. Dual-staining antigen-baits (where an antigen is directly conjugated to two distinct fluorochromes) have now been used to identify HBsAg- and HBcAg-specific B cells with a high degree of reliability and specificity. This system can be used to detect and characterize cells ex vivo or adapted to isolate antigen-specific cells using fluorescence-activated cell sorting.