Genetically Modified Hepatitis B Surface Antigen: A Powerful Vaccine Technology for the Delivery of Disease-Associated Foreign Antigens

The surface antigen of hepatitis B virus (HBsAg) spontaneously aggregates into ‘empty’ virus-like particles (VLPs) in the absence of other viral components. The powerful immunogenicity of HBsAg when administered either as VLPs or as naked DNA invites it's exploitation as a vector for the delivery of antigenic determinants from other organisms. Here we discuss ways in which HBsAg may be modified to derive vaccines against disease-related pathogens. We review studies demonstrating the induction of disease-protective antibody and T-cell responses induced by immunization with recombinant HBsAg vaccines, and consider how these vaccines might best be delivered. Unmodified HBsAg VLPs are licensed for use in humans as the pan-global vaccine to prevent hepatitis B virus infection, suggesting that route-tomarket for recombinant HBsAg vaccines might be simplified.