Exosomes from Ub‑HBcAg‑overexpressing dendritic cells induce T‑lymphocyte differentiation and enhance cytotoxic T‑lymphocyte activity

Hepatitis B virus (HBV) infection is a major public health concern. The clearance of HBV may involve cytotoxic T-lymphocyte (CTL) activity and T helper type 1 reactions. Exosomes generated from dendritic cells (DCs) can induce immunological responses capable of eradicating viruses. However, exosomes loaded with antigens have not yet demonstrated therapeutic potential in HBV infection. Therefore, the present study aimed to investigate the antiviral effects of DC-derived exosomes (Dexs) loaded with ubiquitinated HBV core antigen (Dexs-Ub-HBcAg). Murine bone marrow-derived DCs were loaded with a recombinant lentivector encoding the ubiquitinated form of HBcAg. High-purity Dexs were generated using differential velocity centrifugation. Splenic T-lymphocytes were stimulated with Dexs-Ub-HBcAg and the specific T-cell-mediated immune responses were examined. Cytokine expression was analyzed using enzyme-linked immunosorbent assays. T-lymphocyte proliferation was detected using a Cell Counting Kit-8 assay and HBcAg-specific CTL activity was determined using a lactate dehydrogenase release assay. The results revealed that Dexs-Ub-HBcAg effectively stimulated T-cell proliferation and induced the activation of antigen-specific CTLs to exhibit HBcAg-specific CTL immune responses in vitro. These results suggest the potential of Dexs-Ub-HBcAg for development as a future therapeutic option for the elimination of HBV.