Serum-free cultivation of CEF for vaccine production in microcarrier-systems

Animal cells are a common substrate for production of viral vaccines. Condition of these cells concerning vitality and ability for virus replication is a crucial factor for economic and EP-conform vaccine production. We investigated and optimized a vaccine production process using the primary cell line CEF (chicken embryo fibroblast). State of the art culture systems for this process are roller bottles or cell factories. Furthermore cell culture media containing serum components are used. These systems are cost- and labour intensive and combined with a high contamination risk. So our aim was to develop a production process using a microcarrier-system (Cytodex 1) under serum-free conditions and to compare growth, metabolism and virus replication of the CEF in different culture vessels (cell culture flask, roller bottle, spinner, stirred tank, wave bioreactor®) and under different culture conditions. Here we report on attachment and growth of CEF on microcarrier in serum-free medium and compare virus yields obtained for various culture conditions. Focus will be on comparison between an established stirred-tank reactor and a novel wave bioreactor®. Furthermore we will outline some growth characteristics of these primary cells, we observed during our experimental work, e.g. their high mobility and tendancy to form clusters. This was investigated in more detail under a microscope using a perfusion system. Analyzing these growth characteristics with a small number of cells under defined conditions and permanent visualization could bring explanations for problems we faced in larger scale microcarrier culture of primary CEF