Stimulation of the interleukin-1 receptor and Toll-like receptor 2 inhibits hepatitis B virus replication in hepatoma cell lines in vitro.
BACKGROUND
Toll-like receptors (TLRs) are a key component of the innate immune system and TLR2 has been shown to be involved in the immunopathogenesis of hepatitis B virus (HBV) infection in vivo. We investigated the role of TLR2 stimulation of virus-infected hepatocyte cell lines as a potential antiviral mechanism in vitro.


METHODS
The hepatoblastoma cell line HepG2 was transduced with recombinant HBV baculoviruses and the hepatoma cell line Huh-7 was transiently transfected with complimentary DNA clones of HBV. HBV viral replication was quantified after stimulation with interleukin (IL)-1beta and Pam-2-Cys, a synthetic TLR2 ligand, by measuring intracellular core-associated single-stranded HBV DNA using Southern blot hybridization, as well as viral nucleocapsid formation using a non-denaturing immunoblot method.


RESULTS
Stimulation of both cell lines in vitro with IL-1beta and Pam-2-Cys, both known to induce expression of the pro inflammatory cytokines tumour necrosis factor-alpha and IL-8 via a nuclear factor-kappaB dependent pathway, resulted in the inhibition of HBV DNA replication in the transduced HepG2 cells by up to 90% and nucleocapsid formation in the transiently transfected Huh-7 cells by up to 30%, when compared with mock-treated cells.


CONCLUSIONS
Hepatoma cell lines expressed functional IL-1 receptor and TLR2 receptors, which when stimulated led to a signalling cascade that inhibited HBV replication. These data support an active role for hepatocytes in inhibiting HBV replication and provide a rationale for the development of TLR agonists as potentially novel antiviral agents.
Thompson
Alex J
AJ
Victorian Infectious Diseases Reference Laboratory, North Melbourne, VIC, Australia.
Colledge
Danni
D
Rodgers
Sally
S
Wilson
Rachel
R
Revill
Peter
P
Desmond
Paul
P
Mansell
Ashley
A
Visvanathan
Kumar
K
Locarnini
Stephen
S
D006528:Carcinoma, Hepatocellular / Q000821:virology; D045744:Cell Line, Tumor; D006513:Hepatitis B e Antigens; D006515:Hepatitis B virus / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008024:Ligands; D008113:Liver Neoplasms / Q000821:virology; D017472:Receptors, Interleukin-1 / Q000819:agonists*; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000819:agonists*; D014779:Virus Replication / Q000187:drug effects*
D006513:Hepatitis B e Antigens; D008024:Ligands; D017472:Receptors, Interleukin-1; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2