Figure 1. HBV vector constructs used.

All constructs were based on the wild-type HBV expression plasmid pCH-9/3091 which contains a complete HBV genome. Open reading frames are depicted as yellow boxes. Transcription of the pregenomic (pg) RNA is under control of the CMV-IE promoter. The start sites for transcripts controlled by the endogenous preS1, preS2/S and HBx promoters are indicated by the rightward pointing arrows. “ε” denotes the RNA packaging signal whose interaction with the polymerase initiates pgRNA encapsidation and reverse transcription. The diamond labeled pA symbolizes the HBV polyadenylation signal. In first generation HBV vectors, represented by pCH-S-TG, the transgene (TG) replaced the viral S gene. Here, eGFP, RFP2 and Luc were used as transgenes. These vectors still produce core and X protein, plus truncated forms of polymerase (region covered with dark slash lines) and PreS1/PreS2 (pS1, pS2) gene products. For vector production, functional polymerase and surface proteins are provided in trans by a helper plasmid, e.g. pCH3142 which is identical to pCH-9/3091 except it lacks the “ε” signal. In the pCH-M5-TG vectors, expression of the endogenous HBV gene products was ablated by premature stop codons (blue crosses), or mutation of the preS1 and preS2 initiation codons (downward pointing triangles) so as to engage all preS/S transcripts as TG mRNAs; here TG included truncated MMP-8 (tMMP8). For the chimeric Ad-HBV vectors, Ad-CH-TG, the entire HBV vector expression cassettes from the pCH-M5-TG plasmids were incorporated into ΔE1/ΔE3 Ad-vector backbones. Ad-C-MMP8 contained full-length MMP-8 under CMV promoter control, but no HBV sequences.