In an average influenza season, we face hundreds of thousands of influenza cases. Up to 50,000 deaths per year can be ascribed to influenza epidemics. Nevertheless, this is relatively harmless compared to the current, permanent threat of a worldwide pandemic caused by avian influenza.
AVIR Green Hills Biotechnology is developing innovative seasonal and pandemic influenza vaccines based on the deletion of the NS1 gene (ΔNS1 vaccine) . The vaccine is replication-defective and applied intranasally. Currently, an H1N1 monovalent vaccine is being tested in a clinical phase I study and clinical trials with H5N1 avian influenza vaccine will follow in fall 2007.
A production process, which was successfully employed for the pilot-scale production of H1N1 and H5N1 influenza A virus is presented here. The upstream process is performed according to the specific requirements of the respective influenza subtypes. Currently, 15 L batches are produced in cell factories using Vero (African green monkey kidney) cells. The vaccine bulk is purified by using the very same scheme for all different subtypes. For purification, the cell culture supernatant is clarified by centrifugation and the virus is concentrated by tangential ultra filtration. The concentrated virus is subsequently purified in two chromatographic steps which were co-developed with BIA Separations d.o.o.: First, an anion exchange monolithic column is used. This is followed by size exclusion chromatography for polishing and buffer exchange.
This purification scheme guarantees the thorough depletion of host cell DNA and total protein, and recovers at least 25% of the infectious virus.