Impact of Molecular Modification on the Efficiency of Recombinant Baculovirus Vector Invasion to Mammalian Cells and Its Immunogenicity in Mice

Abstract

The baculovirus display system (BDS), an excellent eukaryotic surface display technology that offers the advantages of safety, efficiency, and economy, is widely used in biomedicine. A previous study using rBacmid-Δgp64-ires-gp64 expressed in low copy numbers of the gp64 gene achieved high-efficiency expression and co-display of three fluorescent proteins (GFP, YFP, and mCherry). However, low expression of GP64 in recombinant baculoviruses also reduces the efficiency of recombinant baculovirus transduction into mammalian cells. In addition, the baculovirus promoter has no expression activity in mammalian cells and thus cannot meet the application requirements of baculoviral vectors for the BDS. Based on previous research, this study first determined the expression activity of promoters in insect Spodoptera frugiperda 9 cells and mammalian cells and successfully screened the very early promoter pie1 to mediate the co-expression of multiple genes. Second, utilizing the envelope display effect of the INVASIN and VSVG proteins, the efficiency of transduction of recombinant baculovirus particles into non-host cells was significantly improved. Finally, based on the above improvement, a recombinant baculovirus vector displaying four antigen proteins with high efficiency was constructed. Compared with traditional BDSs, the rBacmid-Δgp64 system exhibited increased display efficiency of the target protein by approximately 3-fold and induced an approximately 4-fold increase in the titer of serum antibodies to target antigens in Bal B/c mice. This study systematically explored the application of a new multi-gene co-display technology applicable to multi-vaccine research, and the results provide a foundation for the development of novel BDS technologies.

Impact of the Transboundary Interference Inhibitor on RNAi and the Baculovirus Expression System in Insect Cells

“…These plasmids contain an ampicillin resistance gene and an hr5 enhancer upstream of the pie1 promoter. The pFBDM and pUCDM plasmids, which are modified MultiBacs with antibiotics resistance genes inserted via transposition (mini-Tn7 and Cre-loxP), were constructed as described in our prior studies [ 33 ]. Recombinant MultiBacs were generated by utilizing multiple cloning sites (MCS) present in the plasmids (pFBDM and pUCDM) to introduce multiple foreign genes through specific transposition.…”

“…Recombinant MultiBacs were generated by utilizing multiple cloning sites (MCS) present in the plasmids (pFBDM and pUCDM) to introduce multiple foreign genes through specific transposition. E. coli Sw106 containing MultiBac, pHelper, and pGB 2 Ωinv was constructed as described in previous reports [ 33 ]. E. coli Sw106 can directly infect Sf9 cells and enter their cytoplasm to release recombinant MultiBac and generate recombinant baculovirus.…”