The baculovirus infected insect cells are widely used for expression of eukaryotic proteins especially when post-translational modifications and proper disulfide-bond formation are necessary for protein folding and activity. The most common species of baculoviruses used for protein expression studies is the Autographa californica multiple nuclear polyhedrosis virus (AcMNPV), which relies on the lepidopteran species, Spodoptera frugiperda, as its host.
Sf9 cells derived from Spodoptera frugiperda are used for virus production and for protein expression while High5 cells derived from Trichoplusia ni embryo cells are used mainly for protein expression of secreted proteins. Proteins can be produced as native or tagged, individual or with their partner(s) using the muli-bac methodology developed by Imre Berger. The process requires cloning target genes into baculovirus expression plasmids (pVL1393 for intracellular expression or pAcGP67b for secreted proteins), transfection, virus amplification, expression test and protein production (Unger T and Peleg Y., 2012).