(337av) Understanding Dynamics of Adventitious and Cultured Virus Propagation in Plate and Suspension Cell Cultures to Improve Upstream Biomanufacturing Performance

Monolayer culture is a critical format for adventitious agent testing and convenient for small-scale propagation of virus. Additionally, production of viral therapeutics such as vaccines and viral vectors utilize suspension cultures. Understanding the kinetics of infection in these two culture formats can aid in virus production optimization and in utility and sensitivity assessment of alternative adventitious virus detection technologies.

Research Interests

• Mechanistic models describing production of viral therapeutics to determine process dynamics, predict process performance, and optimize productivity.

Measles virus (MeV) propagation has been studied extensively for production of recombinant MeV vectors for viral vaccines and gene therapy applications as well as for oncolytic virus therapy. MeV is commonly produced in bioreactors with microcarrier culture using Vero cells as a production cell line. This process is yet to provide sufficient concentrations of MeV required for therapeutic applications primarily due to the thermal stability of the virus. This temperature-dependent virus inactivation is challenging as it reduces the maximum virus yield in two ways: initial infection by inoculation and the overall production yield. Therefore, it is imperative to know the optimal timing of the infection (TOI) process and the time of virus release to predict the optimal time of harvest (TOH). We have developed a modeling approach to predict the kinetics of MeV infection in Vero cells for the purpose of virus production.

• Determining virus replication kinetics using stochastic spatiotemporal models and transcriptome profiling for development of rapid adventitious agent testing.

The current gold standard for testing of adventitious agents in biotherapeutic production is the in vitro virus assay. However, due to the length of the assay, the need for a non-specific, yet rapid testing technology is critical to ensure accelerated development and patient safety. Understanding viral infection propagation kinetics in monolayer cultures, an essential format for adventitious agent testing, can aid in the development of rapid viral contamination detection tools. Infection kinetics differ in monolayer culture compared to spatially homogeneous systems due to the heterogeneities that arise from the diffusion of virus across the cell layer. In early times of infection when viral concentrations are low, infection is limited by the transport of the viral particles causing spatial heterogeneities that are nontrivial to capturing infection kinetics. Therefore, we aimed to capture early-stage viral infection in monolayer culture to estimate kinetics of infection progression in purposely infected monolayer cultures of Chinese hamster ovary (CHO) cells via a hybrid spatiotemporal model. In addition, transcriptome profiling of CHO cells by typical viral contaminants provides valuable information regarding the cell’s response to infection and the kinetics of infection at a cellular level. Our objective is to use mRNA and microRNA expression profiles to determine early markers of infection for development of rapid adventitious agent testing. In addition, we aim to identify key pathways that are activated in infection and the corresponding microRNAs that control antiviral response in CHO cells.