The mechanism of chronic coxsackievirus B hepatitis in rabbits

Area of Science:

• Virology
• Immunology
• Hepatology

Background:

• Chronic hepatitis is a significant health concern with complex etiologies.
• Understanding viral pathophysiology is crucial for developing effective treatments.
• Coxsackievirus B5 (CVB5) is a known human pathogen, but its role in chronic liver disease requires further investigation.

Purpose of the Study:

• To investigate the pathophysiology of chronic hepatitis induced by Coxsackievirus B5 (CVB5) in a rabbit model.
• To determine the viral localization, host immune response, and potential autoimmune mechanisms involved.

Main Methods:

• New Zealand White rabbits were inoculated with CVB5 (strain Mitchell).
• Samples were collected over 15 months for histological examination, cytokine analysis (IL-6, TNF-alpha, IL-1beta) via ELISA, splenic natural killer (NK) cell function assays, autoantibody detection, and in situ polymerase chain reaction (ISPCR) for viral nucleic acid.
• Viral cultures and sequencing of the viral genome were also performed.

Main Results:

• Histologic evidence of hepatocyte necrosis was observed throughout the study.
• ISPCR confirmed viral nucleic acid localized within hepatocyte cytoplasm, with no evidence in other liver cells.
• No antihepatocyte autoantibodies or elevated intrahepatic cytokine levels were detected.
• A robust neutralizing antibody response to CVB5 was generated, but splenic NK cell function and numbers were significantly reduced.
• Viral cultures were positive at 3 months post-inoculation but negative thereafter.

Conclusions:

• CVB5 (strain Mitchell) induces chronic hepatitis in rabbits, characterized by persistent viral presence in hepatocytes.
• The disease progression does not involve autoimmunity or significant intrahepatic inflammation.
• Impaired natural killer cell function is a key feature of the host response to CVB5 infection.