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Abstract

Influenza is a contagious respiratory tract disease which causes millions of infections worldwide and several hundred thousand of deaths every year. Seasonal prophylactic vaccinations are important to control epidemic outbreaks. In recent years cell culture based influenza vaccine production has been developed replacing conventional production processes using embryonated chicken eggs. In addition to development in upstream processing, new strategies for purification of these cell culture derived antigens are required. As a capturing step, lectin based affinity chromatography was investigated for purification of current influenza strains from cell culture broths. Two topical virus strains (A/Wisconsin/67/2005 (subtype H3N2), B/Malaysia/2506/2004, both from Novartis Behring, Marburg, Germany) and influenza virus A/Puerto Rico/8/34 (H1N1) were produced in MDCK cell cultures and subsequently screened for lectin binding. The alpha-galactose specific Euonymus europaeus lectin (EEL) represented the most suitable ligand for all three virus strains. Using polymer immobilized EEL all investigated influenza viruses could be efficiently captured from MDCK cell culture broths, while the level of contaminating host cell DNA and proteins was highly reduced. Findings suggest that MDCK cell culture derived influenza viruses contain alpha-galactose on their envelope glycoproteins. In contrast, Influenza virus propagated in Vero cells revealed different lectin binding behavior. Here, most favorable binding was achieved by beta-galactose specific Erythrina christagalli lectin (ECL), while EEL could bind only limited amounts of virus. Results demonstrated that lectin affinity chromatography is a valuable capture step for downstream processing of various influenza virus strains. However, the final choice of lectin depended on host cell specific glycosylation of viral proteins. Work is in progress to characterize in detail the binding and purification properties of a reverse genetics derived reassortant H5N1 virus.