Induction of antibody to the "y" determinant of HBsAg in a chimpanzee carrier of HBsAg subtype "adw".

Antibody to the y determinant of hepatitis B surface antigen (HBsAg) was induced in a chimpanzee chronically infected with hepatitis B virus and circulating HBsAg subtype adw. The chimpanzee was immunized with purified preparations of HBsAg subtypes adw and ayw. Six weeks after immunization, antibody to HBsAg (anti-HBs) specific for the y determinant, appeared. No change occurred in titers of HBsAg or antibody to hepatitis B core antigen (anti-HBc) and "e" antigen remained detectable. The circulating HBsAg subtype adw remained present despite the persistence of anti-y for greater than 8 months.