HBV genes induce cytotoxic T‐lymphocyte response upon adeno‐associated virus (AAV) vector delivery into dendritic cells

Summary.  Hepatitis B virus (HBV) has been an increasing problem throughout the world and remains difficult to treat. But immunotherapeutic approaches offer new, effective treatments. Three recombinant adeno‐associated virus (AAV) type 2 vectors, carrying one of the HBV S, C or X gene, were used to load (transduce) professional antigen‐presenting dendritic cells (DC) for the purpose of stimulating cytotoxic T lymphocytes (CTL) in vitro . It was found that all three recombinant AAV/HBV antigen virus loaded DC at approximately 90% transduction efficiency. Most importantly, all three AAV‐loaded DC stimulated rapid, antigen‐specific and major histocompatibility complex (MHC)‐restricted CTL. In vitro , these CTL killed (30–50%) synthetic antigen‐positive autologous targets as well as HepG2 liver cell targets. In comparing the three antigens, it was found that AAV/HBV‐C‐derived CTL consistently had the highest killing efficiency. CTL derived from AAV/HBV‐C‐loaded DC also showed significantly higher killing of targets than that from bacterially generated C‐protein‐loaded DC. Further studies showed that AAV/HBV‐C‐derived CTL had higher interferon (IFN)‐gamma. These data suggest that AAV/HBV antigen gene‐loading of DC may be useful for immunotherapeutic protocols against HBV infection and that the HBV C antigen may be the most useful for this purpose.