A rapid method for titrating baculovirus stocks using the Sf-9 Easy Titer cell line.

A new rapid method for titrating baculovirus stocks has been developed using a novel cell line Sf-9 Easy Titer (Sf-9ET). The Sf-9ET cell line has been transfected with plasmid DNA containing the enhanced green fluorescent protein (eGFP) gene under the control of the baculovirus polyhedrin promoter. When used in the titration assay, the Sf-9ET cells turn green when they are infected with baculovirus due to the activation of the polyhedrin promoter/eGFP complex by baculovirus gene products expressed during the infection. Using a 96-well plate format end-point dilution assay, baculovirus titers can be determined in three days using a fluorescence microscope.