title: Interleukin-12 inhibits hepatitis B virus replication in transgenic mice.
abstract: Interleukin-12 (IL-12) is a heterodimeric cytokine produced by antigen-presenting cells that has the ability to induce gamma interferon (IFN-gamma) secretion by T and natural killer cells and to generate normal Th1 responses. These properties suggest that IL-12 may play an important role in the immune response to many viruses, including hepatitis B virus (HBV). Recently, we have shown that HBV-specific cytotoxic T lymphocytes inhibit HBV replication in the livers of transgenic mice by a noncytolytic process that is mediated in part by IFN-gamma. In the current study, we demonstrated that the same antiviral response can be initiated by recombinant murine IL-12 and we showed that the antiviral effect of IL-12 extends to extrahepatic sites such as the kidney. Southern blot analyses revealed the complete disappearance of HBV replicative intermediates from liver and kidney tissues at IL-12 doses that induce little or no inflammation in these tissues. In addition, immunohistochemical analysis demonstrated the disappearance of cytoplasmic hepatitis B core antigen from both tissues after IL-12 treatment, suggesting that IL-12 either prevents the assembly or triggers the degradation of the nucleocapsid particles within which HBV replication occurs. Importantly, we demonstrated that although IFN-gamma, tumor necrosis factor alpha, and IFN-alpha/beta mRNA are induced in the liver and kidney after IL-12 administration, the antiviral effect of IL-12 is mediated principally by its ability to induce IFN-gamma production in this model. These results suggest that IL-12, through its ability to induce IFN-gamma, probably plays an important role in the antiviral immune response to HBV during natural infection. Further, since relatively nontoxic doses of recombinant IL-12 profoundly inhibit HBV replication in the liver and extrahepatic sites in this model, IL-12 may have therapeutic value as an antiviral agent for the treatment of chronic HBV infection.
authors.affiliation: Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: V J
authors.initials: VJ
authors.lastname: Cavanaugh
authors.forename: L G
authors.initials: LG
authors.lastname: Guidotti
authors.forename: F V
authors.initials: FV
authors.lastname: Chisari
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000235:genetics / Q000502:physiology*; D003588:Cytopathogenic Effect, Viral; D003593:Cytoplasm / Q000821:virology; D005260:Female; D015870:Gene Expression; D006512:Hepatitis B Core Antigens / Q000276:immunology; D006515:Hepatitis B virus / Q000276:immunology* / Q000502:physiology; D007371:Interferon-gamma / Q000235:genetics / Q000502:physiology; D018664:Interleukin-12 / Q000235:genetics / Q000502:physiology*; D007668:Kidney / Q000821:virology; D008099:Liver / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D014779:Virus Replication
chemical_list: D000998:Antiviral Agents; D006512:Hepatitis B Core Antigens; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D007371:Interferon-gamma