Production of functional human bone morphogenetic protein-2 using a baculovirus/Sf-9 insect cell system

A clone of a human Bone Morphogenetic Protein-2 (hBMP-2) cDNA was obtained from a cDNA library established from human dental pulp cells. After subcloning hBMP-2 cDNA into Autographa californica nuclear polyhedrosis virus, the recombinant baculovirus was transfected to Sf-9 cells. Immuno-reactive recombinant hBMP-2 (rhBMP-2) was detected by a polyclonal antibody against Xenopus BMP-2 in the transfected insect cells but not in the culture media. Three days after treatment with the lysate of the transfected Sf-9 cells, increase in alkaline phosphatase activity of a murine stromal cell line, ST2, was detected. Subcutaneous implantation of rhBMP-2 produced in the insect cells induced formation of cartilage, bone and bone marrow in the rats. The present data indicated that the rhBMP-2 preparation produced in the insect Sf-9 cells had a comparable activity to that produced in mammalian cells.