Hepatitis B Core Antigen: Immunology and Electron Microscopy

Abstract

Two distinct viral antigens are associated with the hepatitis B virus: the hepatitis B surface antigen (HB s Ag, Australia antigen) and the hepatitis B core antigen (HB c Ag). HB s Ag, purified from the serum of asymptomatic human HB s Ag carriers, and HB c Ag, purified from the liver of a chimpanzee acutely infected with hepatitis B virus, were examined by serological and immune electron microscopic methods. Antisera raised against HB s Ag reacted with the outer, surface component of the Dane particle and with the 20-nm spherical and tubular particles present in HB s Ag-positive serum, but not with the internal component of the Dane particle or with purified HB c Ag particles. Antisera raised against purified HB c Ag particles reacted with the internal component of the Dane particle and with HB c Ag, but not with the surface of the Dane particle or with the 20-nm spherical and tubular particles associated with HB s Ag. Purified HB c Ag particles, 27 nm in diameter, demonstrated distinct subunits. The infectious form of hepatitis B virus appears to be represented by the 42-nm Dane particle composed of a 27-nm nucleocapsid core component (HB c Ag) surrounded by an antigenically and morphologically distinct lipoprotein surface component (HB s Ag).