Fig. 1

MultiBac-based HCV pseudo particles (bacHCVpp). a Hepatitis C virus (HCV) and HCV pseudo particles (HCVpp) are shown in a schematic representation. Glycoprotein E1 is colored in green, glycoprotein E2 in blue, HCV core in red, HIV gag in light green. HCV in contrast to HCVpp contains also ion channel proteins (p7), lipid droplets on the surface and an RNA genome. b HCVpp was produced with the MultiBac system. A transfer plasmid (pOmniBac1-HCVpp) was used, containing expression cassettes encoding for HCV E1E2 precursor fusion protein on one hand, and for HIV gag protein to initiate budding or particles on the other. The EmBacY baculoviral genome was used to infect Sf21 insect cell cultures for HCVpp production. E1E2, glycoprotein precursor fusion; gag, HIV gag protein; YFP, yellow fluorescent protein; Amp, ampicillin resistance marker; Kan, kanamycin resistance marker, Gn, gentamycin resistance marker; LacZ, blue/white selection marker to identify recombinant baculoviral genome; mini-attTn7, attachment site for integration of heterologous genes by Tn7 transposition; Tn7L and Tn7R, DNA recognition sequences for Tn7 transposase; LoxP, inverted imperfect repeat for Cre-LoxP DNA fusion; IRES, internal ribosomal entry site; 3′NCR, 3′ non-coding region. C, E1, E2, P7, NS2, 3, 4A, 4B, 5A, 5B are HCV proteins. c Results from Western Blot experiments are shown, evidencing HCV E1 and E2 proteins in purified bacHCVpp. MW, Molecular Weight marker; Anti-E1 (H4), primary antibody specific for E1; Anti-E2 (H47), antibody specific for E2; NHS (Normal Human Serum). Alkaline phosphatase coupled Anti-IgG was used as secondary antibody. Molecular weights (in kDa) of marker bands are indicated. d Negative-stain electron micrographs of MultiBac-produced HCVpp (bacHCVpp) are shown. BV denotes baculovirions. Scale bar, 50 nm