Since the 80s, microcarriers have been used to provide growth support for adherent cells in vaccine bio manufacturing processes in scales up to 6000 L. However, most new vaccines are manufactured in smaller scales. For such productions, single-use technology offers an attractive option. The combination of microcarriers and single-use bioreactors has been studied in both stirred-tank and rocking bioreactor formats. The challenge for cultivation with microcarriers is for example shear, the microcarriers need to be maintained in suspension and the culture kept well aerated. These prerequisites can limit the operating conditions, for example, culture volume, under which microcarriers can be used. In this work, we show different approaches for cultivation of Vero cells grown to high cell density by using Cytodex TM microcarriers and/or CytodexTM Gamma microcarriers in serum-free cultivation medium using the ReadyToProcess WAVETM25 bioreactor system. These studies have shown that based on the choice of bioreactor design, operating parameters need to be carefully chosen to avoid excessive shear, which can be detrimental for the cell growth and virus production. Using the tilt function of the rocker, microcarriers were allowed to settle to enable removal of the supernatant prior to infection of the cells with influenza virus and the rocker tilt function allowed also medium exchange with minimal microcarrier loss. Furthermore, the time consuming process of preparation and sterilization of the microcarriers prior to culture was simplified significantly by using pre-sterilized (gamma irradiated) microcarriers. Virus yields were determined as the levels of infectious virus particles and hemagglutinin in the culture supernatants at different time points. These results offer valuable information to facilitate design-in of single-use rocking bioreactor systems and pre-sterilized (gamma irradiated) microcarriers to enable flexible future vaccine productions in smaller scales.

Gamma irradiated microcarrier-based virus production in a single-use rocking bioreactor system

251st National Meeting (2016)

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