Genetic variation of occult hepatitis B virus infection

Figure 2 Secondary structure of the major hydrophilic region of the hepatitis B virus, hepatitis B virus surface antigen. Mutations have been confirmed by functional studies to exert negative effects on antigenicity of hepatitis B virus surface antigen (HBsAg) are shown in green and red circles. Red circles with the Δ symbol denote multiple kinds of amino acid substitutions. These have been substantiated to negatively correlate with HBsAg antigenicity at some sites. The # symbol indicates multiple genotype-specific substitutions. The numbers denote amino acid sites.