Immunochemical and morphological studies of hepatitis B core antigen isolated from the nuclei of hepatocytes.

Immunochemical and morphological properties of hepatitis B core antigen (HBc Ag) were studied in intranuclear particles isolated from human liver. Immunochemical integrity of the purified particles was indicated in the production by guinea pigs of antibody to HBc Ag (anti-HBc) that was immunochemically identical to human anti-HBc. The HBc Ag particles were 27-30 nm in diameter, displayed apparent icosahedral symmetry, and consisted of distinct subunits. The susceptibility of HBc Ag particles to proteolytic and glycolytic enzymes indicated the presence of proteins and glycoproteins. The structural integrity of core particles depended on disulfide, hydrophobic, and hydrogen bonds, and immunological activity relied on intact sulfhydryl groups. Agents active against lipids did not affect immunological reactivity or core structure, as seen by electron microscopy.