Investigation of the Influenza Virus Replication on the Single Cell Level
The annual demand of human influenza vaccines still relies on conventional production in embryonated eggs despite several disadvantages of this technology introduced more than 60 years ago. The establishment of scalable cell culture-based production processes, however, can be crucial to provide sufficient vaccine doses in light of an imminent pandemic thread. Besides process development, the optimization of the smallest production unit, a single infected cell, has an enormous potential to contribute to the progression of cell culture-based production technologies.
Monitoring cell growth and virus propagation in cell cultures yields only average cellular or viral characteristics. However, it has to be assumed that significant differences in the physiological status of cells, progress of infection, and cell-specific virus yields exist. Among genetically identical cells, cellular heterogeneity arises from variation in cell size and cell cycle, fluctuations of cellular constituents and stochastic effects in gene expression. The variability of influenza virions is caused by high mutation rates, diversity in virus particle composition as well as the occurrence of defective interfering particles.
In general, due to the extraordinary heterogeneity in the properties of individual cells, measurement data derived from populations can mask certain effects (e.g. gene regulatory mechanism, fate decisions) leading to wrong interpretations of cellular events. Therefore, over the last years, various tools and technologies for single cell analysis have been developed to answer unresolved questions.
Aim of the project
In this project, we want to utilize new and powerful technologies to investigate the variability of virus infections on the single cell level. Moreover, we are interested in the quantification of stochastic effects to improve mathematical models of the influenza virus replication. Finally, based on an improved understanding of the influenza virus replication, we want to identify bottlenecks limiting cell-specific virus yields, and develop strategies for optimization of host cells or virus strains for cell culture-based influenza vaccine production.