Cell line selection using the Duetz Microflask system

Abstract

The identification of a small number of monoclonal antibody (mAb) producing candidate cell lines from the large number of clones generated post transfection is one of the bottlenecks of cell line development. Clone numbers are reduced significantly during initial medium exchange and static scale up stages but significant numbers can still progress to evaluation in shaking cultures. This is often carried out in shake flasks where the number of clones that can be evaluated may be restricted due to resource limitations. The Duetz Microflask system is a microtitre plate based system which uses ‘Sandwich Covers’ to convert the individual wells of 24 well plates into individual ‘mini reactors’. The ‘Sandwich Covers’ consist of a stainless steel cover, a 0.2µm filter, microfibre inlays and a flexible silicone sealing layer to ensure adequate oxygen transfer rates to individual wells. This work describes the use of the Duetz Microflask system to evaluate cell lines in culture prior to scale up to production shake flasks. We have compared the growth and rank order of performance for a number of cell lines in the Duetz Microflask system with data obtained from shake flasks and demonstrated this system can be used successfully to identify candidate cell lines for further progression. A series of preliminary experiments was completed to determine suitable volumes and operating conditions to minimise evaporation. Unless otherwise stated these were: Fill volume – 1.5mL, Shaker speed – 200rpm, Humidity – 80%.