Evolution and Selection of IAV DIPs
Influenza A virus (IAV) infection poses a global threat to human health. For antiviral therapy, the use of defective interfering (DI) particles (DIPs) might be a promising option. DIPs arise randomly during IAV replication and generally carry an internal deletion in one of their eight genomic viral RNA (vRNA) segments. In a co-infection with infectious standard virus (STV), the DI vRNA replication results in a suppression and interference with IAV replication. The antiviral activity was already demonstrated by rescuing mice and ferrets from a lethal IAV challenge. Previously, cell-culture based production of DIPs in a continuous cultivation system showed periodic oscillations in virus titers due to the dynamic interplay of DIP and STV propagation (Fig. 1,2). Furthermore, de novo generated DI vRNAs accumulated during the production run. We aim to use the continuous culture to study the evolution of IAV DIPs.
Aim of the project
For this concept, a two-stage bioreactor system is utilized. Cells are grown in a cell bioreactor and are continuously transferred to a virus bioreactor for DIP/STV propagation. To monitor STV/DIP dynamics, various virus quantification assays and real-time RT-qPCR are applied. Moreover, imaging flow cytometry is used to investigate intracellular virus replication and apoptosis induction at the single cell level. These data will be used to further refine existing mathematical models.
During the continuous passaging of virus, DI vRNAs are in a mutual competition for cellular and viral resources. Therefore, this set-up is also used to identify and select the “fittest” DIPs, which may serve as possible candidates for antiviral therapy.