Alternative transfection methods for Sf9 cells in vaccine development
July 14-18, 2019
Current CHO and HEK293 platform processes are suitable for a majority of gene-based and protein-based vaccine candidates, but do not always provide adequate production of virus-like particles (VLPs) as observed by inconsistent and low titers. Thus, alternative production platforms are being considered. One option that we are exploring is the use of insect cells as an alternative host, specifically Sf9, since they are biologically well suited to produce VLP’s for mosquito-borne viruses. We first considered a Baculovirus infection method, and successfully produced all components of two VLP’s in our system. However, during initial studies of this process, we encountered issues with the assembly of the VLPs due to the low pH of Sf9 cultures (Figure 1). Thus, we pH adapted Sf9 cells to 7.0 and determined optimal bioreactor parameters to control pH throughout the process. With the capability to maintain cells at this higher pH, the Baculovirus/Sf9 platform looks promising. However, there are additional manufacturing complications to consider. There are concerns with Baculovirus contamination of dual-use equipment and more extensive and costly processing downstream to address viral inactivation and isolation. Thus, we are also considering a transient transfection process.
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Abasha Williams, Daniel Schankel, Elizabeth Scheideman, Frank Arnold, and Elle Millender, "Alternative transfection methods for Sf9 cells in vaccine development" in "Biochemical and Molecular Engineering XXI", Christina Chan, Michigan State University, USA Mattheos Koffas, RPI, USA Steffen Schaffer, Evonik Industries, Germany Rashmi Kshirsagar, Biogen, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/biochem_xxi/58