Proteome analysis of virus-host cell interaction: rabies virus replication in Vero cells in two different media

The use of Vero cells for rabies vaccine production was recommended from the WHO in 2005. A controlled production process is necessary to reduce the risk of contaminants in the product. One step towards this is to turn away from animal-derived components (e.g. serum, trypsin, bovine serum albumin) and face a production process in animal component-free medium. In this study, a proteomic approach was applied, using 2-D differential gel electrophoresis and mass spectrometry to compare rabies virus propagation in Vero cells under different cultivation conditions in microcarrier culture. Protein alterations were investigated for uninfected and infected Vero cells over a time span from 1 to 8 days post-infection in two different types of media (serum-free versus serum-containing media). For mock-infected cells, proteins involved in stress response, redox status, protease activity or glycolysis, and protein components in the endoplasmic reticulum were found to be differentially expressed comparing both cultivation media at all sampling points. For virus-infected cells, additionally changes in protein expression involved in general cell regulation and in calcium homeostasis were identified under both cultivation conditions. The fact that neither of these additional proteins was identified for cells during mock infection, but similar protein expression changes were found for both systems during virus propagation, indicates for a specific response of the Vero cell proteome on rabies virus infection.