Rapid titer assay of adenovirus containing green fluorescent protein gene using flow cytometric analysis

The plaque assay has been widely used for titration of adenovirus (AdV). Ho wever, it takes usually 2-3 weeks, so this slow assay often impedes bioproc ess development of large-scale AdV production. In this study, we developed a rapid AdV titration assay that can be done within a day. Further, unlike the plaque assay, this assay does not require a laborious serial dilution o f samples. This rapid assay can be achieved by using green fluorescent prot ein (GFP) as a marker gene and flow cytometric analysis. It yields a good c orrelation between infectious titer of AdV harboring GFP and flow cytometri c parameters such as average green fluorescence intensity or % of infected cells. Taken together, this rapid assay will facilitate bioprocess developm ent for efficient large-scale AdV production.