The ultrastructural morphology of native hepatitis B virus

Abstract

Cell lines (2.2.15 cells) capable of supporting the replication of hepatitis B virus (HBV) DNA and intact viral particles have been established by HBV DNA transfection into HepG2 cells. The purpose of this study was to determine the ultrastructural morphology of native HBV particles without purification in the culture supernatants and in sera from patients. Electron microscopy (EM) and immunogold EM of the samples were carried out using polyclonal and monoclonal anti-hepatitis B surface antigen antibodies. HBV particles in the purified samples from the culture supernatants by density-gradient centrifugation were examined to compare the morphology with that of unpurified samples. EM and immunogold EM studies demonstrated the presence of Dane particles (41.8 nm in diameter), cobra-shaped (head diameter, 42.4 nm), and horn-shaped (head diameter, 43.5 nm) particles in the culture supernatants and in the sera from two patients. The tail of the cobra-like particles had a diameter of 21.0 nm and a length of 214 nm. The hornlike particles had a long branch 20.1 nm in diameter with a length of 189 nm, and a short branch 21.4 nm in diameter with a length of 112 nm. The ratio of Dane particles and cobra- and horn-shaped particles in the supernatants was 5 : 4 : 1. After ultracentrifugation, the cobra- and horn-shaped particles completely disappeared; there were only Dane particles together with spheres of 22 nm and filaments. In conclusion, this study showed for the first time that the native replicative form of HBV is cobra- and horn-shaped.

Ultrastructural Evidences of Hepatitis B Infection in Human Liver Biopsies Disclose Complex Assembly and Morphogenesis Pathways for Hepatitis B Virus

“…They resembled the previously described tadpole or cobra-shaped and horn-shaped particles [1,[11][12][13] . A recent report suggested that these particles are the native replicative form of HBV [13] .…”

“…They resembled the previously described tadpole or cobra-shaped and horn-shaped particles [1,[11][12][13] . A recent report suggested that these particles are the native replicative form of HBV [13] . However, in agreement with this study, previous reports had shown the presence of Dane's particles connected to the vesicle membrane through either a short or a long stalk 20 nm in diameter [10,31] .…”

“…SVP have also been observed in great excess over virions. Moreover, other ultrastructural forms of HBV named tadpole-or cobra-shaped HBV with a head measuring 42 nm and a tail with 22 nm in diameter and hornshaped HBV with a head and two branches of different length have also been reported [1,[11][12][13] . Despite of recent advances on acknowledge of HBV structure and biology, little is known about the morphogenesis and release of virions [14] .…”

Hepatitis B virus directly promotes collagen I expression of LX‐2 cells without infection in vitro

“…In order to identify the pathway responsible for HBV‐induced collagen type I expression, we performed blocking experiments. TGF‐β1 is a potent factor in stimulating collagen type I gene transcription 11 . TGF‐β and TNF‐α response elements have been identified in the COL1A1 and COL1A2 genes 12 .…”

Ultrastructural demonstration of hepatitis B virus production in a mouse model produced by hydrodynamic transfection

“…Recently, we observed unique native HBV particles, named cobra-shaped and horn-shaped, in chronic hepatitis B patient serum without ultracentrifugation (29). These unique particles have been shown to completely disappear after ultracentrifugation.…”