Abstract
The use of baculovirus vectors shows promise as a tool for gene delivery into mammalian cells. These insect viruses have been shown to transduce a variety of mammalian cell lines, and gene transfer has also been demonstrated in vivo. In this study, we generated two recombinant baculovirus vectors displaying an integrin-specific motif, RKK, as a part of two different loops of the green fluorescent protein (GFP) fused with the major envelope protein gp64 of Autographa californica M nucleopolyhedrovirus. By enzyme linked immunosorbent assays, these viruses were shown to bind a peptide representing the receptor binding site of an α2 integrin, the α2I-domain. However, the interaction was not strong enough to overcome binding of wild type gp64 to the unknown cellular receptor(s) on the surface of α2 integrin-expressing cells (CHO-α2β1) or enhance the viral uptake. After treatment of these cells with phospholipase C, internalization of all viruses was blocked or decreased significantly. However, one of the RKK displaying viruses, AcGFP(K)gp64, was still able to internalize into CHO-α2β1 cells, although at a lower level as compared to non-treated cells. This may indicate the possible utilization of a PLC independent alternative route via, in this case, the α2β1 integrin.
