Cytotechnology

, Volume 54, Issue 1, pp 35–48

Using cell size kinetics to determine optimal harvest time for Spodoptera frugiperda and Trichoplusia ni BTI-TN-5B1-4 cells infected with a baculovirus expression vector system expressing enhanced green fluorescent protein

Method in Cell Science

DOI: 10.1007/s10616-007-9064-5

Cite this article as:
Sander, L. & Harrysson, A. Cytotechnology (2007) 54: 35. doi:10.1007/s10616-007-9064-5
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Abstract

Infecting insect cells with a baculovirus expression vector system (BEVS) is an increasingly popular method for the production of recombinant proteins. Due to the lytic nature of the system, however, determining the optimal harvest time is critical for maximizing protein yield. We found that measuring the change in average diameter during the progress of infection with an automated cell analysis system (Cedex HiRes, Innovatis AG) could be used to determine the time of maximum protein production and, thus, optimal harvest time. As a model system, we use insect cells infected with a baculovirus expressing enhanced green fluorescent protein (EGFP). We infected two commonly used insect cell lines, Spodoptera frugiperda (Sf-9) and Trichoplusia ni BTI-TN-5B1-4 (Hi5) with an Autographa californica nuclear polyhedrosis virus (AcNPV) encoding EGFP at various multiplicities of infection (MOI). We monitored the progress of infection with regard to viability, viable cell density and change in average cell diameter with a Cedex HiRes analyzer and compared the results to the EGFP produced. Peak protein production was reached one to two days after the point of maximum average diameter in all conditions. Thus, optimal harvest time could be determined by monitoring the change in average cell diameter during the course of an infection of a cell culture.

Keywords

BaculovirusBEVSSf-9Hi5Cell size kineticsAverage cell diameterEGFPCedex HiRes

Abbreviations

BEVS

baculovirus expression vector system

Sf-9

Spodoptera frugiperda

Hi5

Trichoplusia ni BTI-TN-5B1-4

AcNPV

Autographa californica nuclear polyhedrosis virus

EGFP

enhanced green fluorescent protein

MOI

multiplicity of infection

Pfu

plaque forming units

RFI

relative fluorescence intensity

PI

post-infection

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  1. 1.Innovatis AGBielefeldGermany
  2. 2.AstraZenecaMolndalSweden