Efficacy of hepatitis B vaccine in chimpanzees given transfusions of highly infective blood

HBV-associated ultrastructures in the chimpanzees' livers with experimental hepatitis B

An electron-microscopic study was carried out using chimpanzees' livers infected with experimental hepatitis B for the elucidation of intracellular development of HBV-associated ultrastructures and extracellular release of HBV. Core particles were first detected in the nucleus of liver cells at around the time of the first seropositiveness for HBsAg, and then in the cytoplasm. Subsequently, their budding into endoplasmic reticular cisterna was seen together with other core particles in the surrounding cytoplasm. Dane-like particles were seen in the cisterna, and also extracellularly nearby a liver cell with a marked proliferation of microvilli at the onset of liver cell injury. Thereafter, core-like particles were seen within electrondense amorphous material at the site of the contact between liver cell and lymphocyte. The above sequence of features suggested us the assembly of core particles and surface envelope at the cisternal membrane of endoplasmic reticulum, and a reversed pinocytosis whereby Dane or HBV particles were released extracellularly. The filamentous structures within endoplasmic reticular cisternae, which were thought to be HBsAg, were never detected.

Ultrastructural studies on liver cell necrosis and lymphocytes in experimental hepatitis B

Ultrastructural studies on liver cell necrosis and the interaction of lymphocyte and liver cell were carried out in experimental hepatitis B in chimpanzees. Two types of liver cell necrosis were identified. One was a lytic necrosis, and the other was a coagulation necrosis. Both types of liver cell necrosis were closely associated with the apposition of lymphocytes. The interaction (or close contact) of lymphocyte and non-necrotic liver cell infected with HBV was also detected. There were two distinct patterns of the contact. One was the direct contact, and the other was the contact with the intervention of electron-dense fuzzy material containing 20 to 22 mu spherical particles and 51 to 55 mu double-layered spherical particles. The ultrastructural characteristics of lymphocytes in each pattern of the contact were different. The results suggested that the pathogenesis of liver cell necrosis in hepatitis B was closely associated with the action of lymphocytes, and two modes of lymphocytic reaction were conceivable.