Human growth hormone gene expression in vitro following rAAV2/1-mediated gene transfer

Background: Viral vectors can produce longer-lasting effects than a recombinant protein. Objective: Develop a system of sustained GH1 (a human growth hormone gene) transfer and expression in baby hamster kidney cell (BHK-21) line using recombinant adeno-associated viral vectors pseudotyped with viral capsids from serotype 1 (rAAV2/1). Methods: The expression of GH1 in vitro was examined by reverse transcription polymerase chain reaction and Western blot analysis. Effects of GH1 on cell proliferation were measured by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT) experiments. Mice serum IGF-1 and blood glucose, after injection of virus infected BHK-21 cells, were measured by enzyme-linked immunosorbent assays. Results: rAAV2/1-mediated GH1 gene transfer occurred effectively in vitro after 48 hours of transduction at 1105 vg/mL (multiplicities of infection). MTT experiments indicated notable effects of the GH1 gene on cell proliferation in vitro. Subsequent animal experiment suggested that the injection of virus infected BHK-21 cells might induce increase of serum IGF-1. Conclusion: Our study shows the feasibility of rAAV2/1-mediated GH gene delivery in vitro, applicable for future experimental and clinical investigations. Keywords: Baby hamster kidney cell 21, growth hormone, insulin-like growth factor 1, recombinant adenoassociated virus vector