Electron microscopy of ribonucleic acid in nuclear particulate aggregates of hepatitis D using nuclease-gold...

The ultrastructural localization of hepatitis delta antigen (HDAg) and ribonucleic acid (RNA) was investigated by immunoperoxidase electron microscopy and by enzyme electron microscopy of RNase-gold complexes on liver biopsies from seven patients with hepatitis D. HDAg was localized mainly in the nucleus and sometimes in the cytoplasm of hepatocytes. Ultrastructurally, intranuclear HDAg was found on nuclear particulate structures measuring 20 to 30 nm in diameter. Intranuclear RNA visualized with gold particles was found in high amounts in the nucleolus, to a small extent in the chromatin area, and also on nuclear particulate structures. These findings suggest that intranuclear aggregates of irregular granular particulate structures in hepatitis D are the internal component of hepatitis delta virus (HDV) particles in blood.