Tangential Flow Filtration for the Concentration of Oncolytic Measles Virus: The Influence of Filter Properties and the Cell Culture Medium.

Daniel Loewe,Tobias Weidner,Tanja A Grein,Peter Czermak,Denise Salzig,Hauke Dieken

doi:10.3390/membranes9120160

Abstract

The therapeutic use of oncolytic measles virus (MV) for cancer treatment requires >108 infectious MV particles per dose in a highly pure form. The concentration/purification of viruses is typically achieved by tangential flow filtration (TFF) but the efficiency of this process for the preparation of MV has not been tested in detail. We therefore investigated the influence of membrane material, feed composition, and pore size or molecular weight cut-off (MWCO) on the recovery of MV by TFF in concentration mode. We achieved the recovery of infectious MV particles using membranes with a MWCO ≤ 300 kDa regardless of the membrane material and whether or not serum was present in the feed. However, serum proteins in the medium affected membrane flux and promoted fouling. The severity of fouling was dependent on the membrane material, with the cellulose-based membrane showing the lowest susceptibility. We found that impurities such as proteins and host cell DNA were best depleted using membranes with a MWCO ≥ 300 kDa. We conclude that TFF in concentration mode is a robust unit operation to concentrate infectious MV particles while depleting impurities such as non-infectious MV particles, proteins, and host cell DNA.

Highlights

Oncolytic viruses are a promising class of therapeutics for the treatment of late-stage cancer because they infect and lyse cancer cells [1]
We considered different membrane materials (PES and xRC), molecular weight cut-off (MWCO) (100 nm, 300 kDa and 100 kDa), and two different feeds (SCM and serum-free medium (SFM))
Regardless of the membrane material and feed, only a MWCO ≤ 300 kDa was suitable for the concentration of infectious measles virus (MV) particles

Summary

Introduction

Oncolytic viruses are a promising class of therapeutics for the treatment of late-stage cancer because they infect and lyse cancer cells [1]. The deeper understanding of MV production gained from these studies has shown that shear stress and aeration play a key role in process productivity [7] By optimizing these parameters, MV titers of up to 1010 TCID50 mL−1 have been produced in bioreactors [7]. The higher upstream productivity has shifted the focus to downstream processing (DSP), which must concentrate the MV particles and purify them according to regulatory guidelines. This requires the depletion of impurities such as host cell proteins (typical threshold: 100 ng mL−1 ) and Membranes 2019, 9, 160; doi:10.3390/membranes9120160 www.mdpi.com/journal/membranes

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Conclusion