Expression of the fusion protein recombinant human granulocyte-macrophage colony stimulating factor and leukemia inhibitory factor in a baculovirus vector system.

A fusion gene coding human granulocyte-macrophage colony stimulating factor (GM-CSF) and leukemia Inhibitory factor (LIF) cDNAs was inserted Into the transfer vector pSXIVVI + X3 with the control of Syn and XIV promoters. The Sf9 cells (Spodoptera frugiperda) were co-transfected with the recombinant plasmid and TnNPV DNA (Trichoplusia ni nuclear polyhedrosis virus DNA). The fusion protein recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) and leukemia inhibitory factor (LIF) could be synthesized In cells Infected with recombinant virus at a level of about 23% of their total cellular protein. Activity analysis of the fusion protein in Infected cells revealed that it exhibited the dual activities of GM-CSF and LIF. Western blot analysis of the expressed fusion protein in infected larvae showed that the virus-mediated fusion protein, with a molecular weight of ∼35 kDa, is confirmed with immunoreactivity.