Murine interleukin-4 production with baculovirus: an easy and rapid method for a small scale production of functional interleukins.

We described a baculovirus expression system for high level production of secreted murine recombinant IL-4. We have constructed a recombinant baculovirus based on Autographa californica polyhedrosis virus, containing both a synthetic PCR-derived murine IL-4 cDNA under the control of the polyhedrin promoter and the lacZ gene under the control of the P10 promoter to allow an easy detection of recombinant virus. The baculovirus IL-4 was fully functional in biological assay and was present under two glycosylated forms in the supernatants of infected Sf9 cells. We also detected a third unglycosylated intracytoplasmic form resulting from a fusion between the 35 first amino acids of polyhedrin and the murine IL-4. Finally, confocal microscopy showed that this recombinant protein was secreted along a classical pathway like in mammalian cells.