TIPS: Titerless Infected-Cells Preservation and Scale-Up

by David J. Wasilko and S. Edward Lee, PhD
Volume 5, Issue 3 (Fall 2006)

Baculovirus, particularly AcMNPV (Autographa californica multiple nucleocapsids polyhedrosis virus), is widely used for heterologous protein expression. There are several shortcomings in the current practice of preserving and scaling up baculovirus: 1) extracellular baculovirus stocks, routinely prepared in large volumes and stored at 4º C, are often unstable; 2) laborious and time-consuming steps to amplify and titer the baculovirus stocks are often necessary, and generally recommended, for achieving consistent viral infection and protein expression; 3) once prepared, the baculovirus is suspended and stored in conditioned medium. Given the complex, undefined, and unstable nature of the spent media components, including proteases and nucleases, protein expression tends to vary even when steps are taken to titer the virus stock and adjust the amount of stock used for infection. Here, we will report a new method for preserving and scaling up baculoviruses that: 1) provides a new form of viral stock more stable than the traditional, extracellular stock; 2) eliminates the need for virus amplification and retitering; 3) drastically reduces the turn-around time and resources required for scale-up; and 4) improves yield and consistency in protein expression.

Wasilko DJ, Lee SE. TIPS: Titerless Infected-Cells Preservation and Scale-Up. BioProcess J, 2006; 5(3): 29-32.