In the present study, we demonstrated that the dual-function vector not only suppressed HBV replication by silencing HBx, which reduced HBV load, but also enhanced TLR7-mediated type I IFN and immunostimulatory cytokine production while inhibiting immunosuppressive cytokines, which helped to recover adaptive immunity and further promoted the
inhibition of HBV replication. By comparing the effects of ssRNA, shRNA, and ssRNA-shRNA dual functional vector on HBV replication or immune stimulation, we found that ssRNA-shRNA dual functional vector was the strongest inhibitor of HBV replication and the most efficient stimulator of innate immunity both in vitro and in vivo. The dual functional vector was more efficient to stimulate type I IFN response than ssRNA, possibly because the relief of HBV-induced immune tolerance after direct HBV load Gefitinib decreased. It exerted a stronger Pictilisib clinical trial inhibitory effect on HBV replication than shRNA, possibly due to its arousing of IFN response by activation of the TLR7 pathway. We propose that both HBx silence and ssRNA-induced TLR7 activation contribute to the reversal of the HBV-intrinsic immune tolerance by a dually functional vector. Furthermore, dual-vector therapy reestablished HBV-specific CD8+ T-cell and anti-HBs Ab responses as well as effectively cleared HBV infection, demonstrating that reversing cell-intrinsic immunotolerance by this therapy further
promotes the recovery of anti-HBV adaptive immunity. To our knowledge,
this is the first report to propose that systemic immunotolerance can be overcome by reversing hepatocyte-intrinsic tolerance. Up to now, there has been no ideal mouse model that can mimic HBV check details natural infection. Although several lines of transgenic mice expressing either HBs gene or full-length HBV genome have been established, the immune system in these HBV-transgenic mice is inherently tolerant to transgene products; HBV replication is generated from the integrated HBV sequence harbored in all hepatocytes, which is clearly different from the natural HBV persistence. So these HBV-Tg mice cannot be used to study peripheral tolerance. The mouse model established by a single hydrodynamic injection of pAAV/HBV1.2 DNA into the tail veins of C57BL/6 mice is the first good model to observe the immune response/tolerance in immunocompetent mice, in which HBV surface antigenemia persists for >6 months, and viral replication intermediates, transcripts, and proteins present in liver tissues for up to 1 year.8 Moreover, there was no neutralizing anti-HBs antibody production after HBsAg/CFA vaccination, suggesting the generation of tolerance. The characteristics of this mouse model for HBV persistence are thought comparable to those of human chronic HBV infections in the immune tolerant stage. A series of studies have used this model to research HBV persistence.