OBJECTIVETo elucidate the roles of Toll-like receptor 3 (TLR3) on dendritic cells (DCs) in HBV infection.

METHODSPeripheral blood mononuclear cells (PBMCs) were isolated from 48 healthy volunteers (HV) and 50 chronically HBV-infected patients (CH). DCs were induced and proliferated in a culture medium with rhGM-CSF and rhIL-4. We stimulated DCs with poly I:C and then TLR3, HLA-DR, and CD86, and CD1a expressions were examined by flow cytometry at 0 h, 12 h, 24 h and 48 h. The mRNA expressions of TLR3 were quantified by real-time PCR.

RESULTSTLR3 expression on DCs before the poly I:C stimulation and afterwards on the 12 h, 24 h, and 48 h were 69.2%+/-20.4%, 76.0%+/-18.6%, 78.2%+/-19.5% and 85.5%+/-6.9% respectively in the CH group, and 70.8%+/-11.2%, 67.5%+/-20.9%, 86.3%+/-14.7%, 68.6%+/-16.9% in the HV group. The expressions of TLR3 were up-regulated significantly at 24 h and 48 h after stimulation with poly I:C in the HV group, and in the CH group they were not significantly increased at 24 h but obviously increased at 48 h. The mRNA expressions of TLR3 increased significantly at 12 h in the HV groups, and at 48 h in CH group. The rate of CD86 expressions increased after poly I:C stimulation, and the increased rates were 12.6%+/-9.8%, 23.8%+/-20.0%, 20.7%+/-14.3% in the CH group, and 31.0%+/-25.0%, 43.4%+/-24.7%, 44.6%+/-25.5% in the HV group at 12 h, 24 h and 48 h after poly I:C stimulation. There was a marked increase of the expression level of CD86 in the HV group. In contrast, the level was only slightly increased in the CH group (31.0% vs 12.6%). The differences between the two groups were significant at 24 h and 48 h. No significant differences were detected in HLA-DR and CD1a between the two groups.

CONCLUSIONSThe increase of expression level of TLR3 is slower in the CH group than that in the HV group. A marked increase of the expression level of CD86 is observed in the HV group. Our results suggest that abnormal expression of TLR3 and CD86 may relate to the persistence of HBV infection.