Effect of cell concentration and multiplicity of infection on the production of recombinant baculoviruses in insect cell cultures

Abstract

The insect cell-baculovirus expression system is versatile and useful for the production of recombinant proteins. It consists in infecting insect cell cultures with a recombinant baculovirus that contains the gene of interest. An important limitation of the system is the limited availability of baculoviral stocks with high titers of infectious particles (plaque forming units, pfu). In this work, the effect of multiplicity of infection (MOI) and cell concentration at the time of infection (CCI) on the yield of baculovirus infectious particles was investigated. Combinations of two values for MOI (0.1 or 1 pfu/cell) and CCI (1 or 2 x106 cel/mL) were tested. Kinetics of cell growth, total protein and gp64 concentrations in the culture supernatant, and the baculovirus titer at the time of harvest were determined. The highest viral titers, 3.8 ± 2 x108 pfu/mL, were obtained in cultures infected at a MOI = 0.1 pfu/cell and a CCI = 1x106 cell/mL. Such cultures had the lowest cell growth after infection. The results obtained in this work can be used for the efficient production of baculovirus stocks with high viral titers.