Novel approaches to oral immunization for hepatitis B.

Hepatitis B is a necroinflammatory liver disease manifested with subacute to acute symptoms, liver cirrhosis, and mortality. Parenteral alum-adsorbed hepatitis B surface antigenic (HBsAg) vaccination, although available, poses serious concerns regarding inability to induce both cell-mediated and mucosal immune response. In this context, oral delivery may be a prospective solution to the issues associated with conventional vaccination. However, the strategy is detrimental to the antigenic substances, suffers various physical/chemical barriers, and impedes poor transcytosis via mucosal route. Therefore, surface-engineered novel carrier-based approaches are reportedly promising for effective HBsAg oral vaccine delivery. This review focuses on the efforts for developing oral mucosal vaccine against hepatitis B, with considerable attention on novel drug delivery systems for spatial distribution of antigenic substance to the immune effector cells and organs.