Expression and characterization of albumin fusion protein canine IFNγ-CSA in baculovirus-insect cell expression system

In this study, canine IFNγ was fused by a flexible linker with canine serum albumin to construct the fusion protein IFNγ-CSA for the purpose to design a long-acting canine IFNγ. The fusion protein was successfully expressed in baculovirus-infected Sf9 insect cells and was purified by salting-out and ion exchange chromatography. The IFNγ-CSA fusion possessed potent anti-viral assay against vesicular stomatitis virus in cultured cells. IFNγ-CSA was also stable at 37 °C up to 72 h compared with 8 h for IFNγ alone. In vivo pharmacokinetics demonstrated a significantly longer half-life for IFNγ-CSA (15.42 h) than for canine reIFNγ (1.51 h) in KM mice. These results indicate that IFNγ-CSA expression in the baculovirus system was successful and provide a promising long-acting cytokine for veterinary clinical applications.