High level expression of human granulocyte colony stimulating factor(hG-CSF) in silkworm cells and larvae

The cDNA of hG-CSF containing signal sequence was cloned into M13mp18 vector,and the sequence analysis showed that the cloned fragment was the high active form of hG-CSF. Insertion of the hG-CSF cDNA into BmNPV transfer vector pBE284, formed a recombinant transfer vector pBE284-G. BmN cell was cotransfected with wild type viral DNA and pBE284-G. The recombinant virus BmG-CSF was obtained by homologous recombination in vivo. Southern-hybridization analysis suggests that the recombinant viral DNA contains hG-CSF cDNA fragment. The biological activity of G-CSF was 1. 2 �� 10 6CFU/ml at day 4 in the supernatant of BmN cell culture infected with BmG-CSF and was 1. 4 �� 10 7CFU/ml at day 4 in the hemolymph of silkworm larvae infected with BmG-CSF.