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Abstract

When changing from vaccine production in chicken eggs or static cell cultures (rollerbottles) to a production using complex fermentation technology with virus replication in animal cells grown on microcarriers, many aspects of such processes have to be evaluated1-5. In human and veterinary vaccine production influenza is of great importance. We therefore chose the process of equine influenza vaccine production (equine influenza Newmarket 1/93 H3N8) in MDCK cells as an example, to start optimizing such processes by acquisition of many data on different levels to improve this process regarding viral yield and reproducibility together with efficacy, purity and safety of the vaccine. At present, we focus on optimization of cell growth and virus titers, scale-up, high cell density cultures and characterization of virus particles. Besides standard on-line and off-line data such as the concentration of glucose, lactate, ammonia or proteases, cell growth on microcarriers and virus titers are analyzed. The amino acid composition of the cell culture medium is measured using a new technique: anion exchange chromatography together with pulsed amperometric detection6. In contrast to the traditional amino acid analysis this technique allows the quantification of at least 20 amino acids without prior sample preparation. Some aspects of this method optimized for cell culture medium analysis will be discussed and the results obtained for different batches of virus production will be presented. Amino acid concentration profiles during cell growth and virus production will be compared with other on- & off-line data, to evaluate the importance of some amino acids in different phases of cell metabolism.