title: Effect of interferon-gamma on hepatitis B viral antigen expression in primary hepatocyte culture.
abstract: Interferon-alpha has been shown recently to selectively enhance hepatocyte expression of HBsAg/pre-S2 in chronic hepatitis B virus infection in a way that may enhance immune recognition. To determine the effect of interferon-gamma on hepatitis B virus antigen expression, hepatocytes isolated from patients with chronic hepatitis B virus infection were incubated in the absence or presence of interferon-gamma and viral antigen expression was assessed by both radioimmunoassay and immunocytochemistry using appropriate monoclonal antibodies. Interferon-gamma inhibited the expression of all hepatitis B virus antigens tested. Intracellular HBsAg measured by radioimmunoassay of sonicated hepatocytes fell by 29% with 1 U/ml (p less than 0.01) and 36% with 10 U/ml of interferon-gamma (p less than 0.001) compared with control treatment. Secreted HBsAg was reduced by 19% with 10 U/ml of interferon-gamma (p less than 0.01). Intracellular HBeAg was also decreased by 29% with 1 U/ml (p less than 0.05) and 42% with 10 U/ml of interferon-gamma (p less than 0.05), but no significant change was found in the amount of secreted HBeAg. The proportion of hepatocytes containing various hepatitis B virus antigens and the intracellular viral antigen staining densities also fell significantly with interferon-gamma incubation. Interestingly, the addition of interferon-gamma abolished the augmenting effect of interferon-alpha on intracellular HBsAg. These data indicate that interferon-gamma, in contrast to interferon-alpha, has an inhibitory effect on hepatocyte expression of all hepatitis B virus antigens including HBsAg/pre-S2, suggesting that this may be one factor that accounts for their difference in clinical activity in patients with chronic hepatitis B virus infection.
authors.affiliation: Institute of Liver Studies, King's College School of Medicine and Dentistry, London, United Kingdom.
authors.forename: J Y
authors.initials: JY
authors.lastname: Lau
authors.forename: V G
authors.initials: VG
authors.lastname: Bain
authors.forename: N V
authors.initials: NV
authors.lastname: Naoumov
authors.forename: H M
authors.initials: HM
authors.lastname: Smith
authors.forename: G J
authors.initials: GJ
authors.lastname: Alexander
authors.forename: R
authors.initials: R
authors.lastname: Williams
mesh_terms: D002478:Cells, Cultured; D004338:Drug Combinations; D006511:Hepatitis B Antigens / Q000276:immunology*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000276:immunology*
chemical_list: D004338:Drug Combinations; D006511:Hepatitis B Antigens; D016898:Interferon-alpha; D007371:Interferon-gamma