Modified influenza virus neuraminidases are described herein that improve viral replication, thus improving the yield of vaccine viruses. Expression of such modified neuraminidases by influenza virus may also stabilize co-expressed hemagglutinins so that the hemagglutinins do not undergo mutation or decrease the need for HA binding to cells.

Provided is a production method for reassortant influenza virus having genome segments of two or more kinds of influenza virus in the case where an antigenic strain and donor strain have similar antigenicities. The production method makes use of the first influenza virus containing an antigenic protein, the second influenza virus having an antigenic protein having antigenicity similar to that of the strain, and the third influenza virus having an antigenic protein having antigenicity different from that of the strain, and includes the steps of: coculturing the strain and the strain by infecting a host therewith, to produce reassortant influenza viruses; selecting influenza virus having the antigenic protein from the viruses; then coculturing the strain and the selected strain by infecting a host therewith; and selecting influenza virus having the antigenic protein from reassortant influenza viruses produced from the strain and the strain.

Influenza viruses for use in preparing human vaccines have traditionally been grown on embryonated hen eggs, although more modern techniques grow the virus in mammalian cell culture e.g. on Vero, MDCK or PER.C6 cell lines. The inventor has realised that the conditions used for influenza virus culture can increase the risk that pathogens other than influenza virus may grow in the cell lines and have identified specific contamination risks. Suitable tests can thus be performed during manufacture in order to ensure safety and avoid iatrogenic infections.

A number of improvements for preparing vaccine antigens from disintegrated influenza viruses are disclosed. A splitting step can be followed by detergent exchange. Splitting can take place in the presence of a buffer with a higher ionic strength and/or in the presence of phosphate buffer.

Disclosed is an adapted Madin-Darby canine kidney cell line capable of suspension culture in the absence of serum, and a chemically-defined medium for culture of the adapted MDCK cell line. Further disclosed are culture methods for growing the adapted MDCK cell line and methods for producing a vaccine from the adapted MDCK cell line grown in the chemically-defined medium.

Disclosed is an adapted Madin-Darby canine kidney cell line capable of suspension culture in the absence of serum, and a chemically-defined medium for culture of the adapted MDCK cell line. Further disclosed are culture methods for growing the adapted MDCK cell line and methods for producing a vaccine from the adapted MDCK cell line grown in the chemically-defined medium.

The present application discloses stability-indicating potency assays for influenza vaccines.

Methods for separating AAV empty capsids from mixtures of AAV vector particles and AAV empty capsids are described. The methods use column chromatography techniques and provide for commercially viable levels of recombinant AAV virions.

Embodiments herein relate to compositions of and methods for live viruses. In certain embodiments, a live, attenuated virus composition includes, but is not limited to, one or more live, attenuated viruses and compositions to reduce inactivation and/or degradation of the live, attenuated virus. In other embodiments, the live, attenuated virus composition may be a vaccine composition. In yet other compositions, a live, attenuated virus composition may include at least one carbohydrate, at least one protein and at least one high molecular weight surfactants for reducing inactivation and/or degradation of the live, attenuated virus.

A process for the purification of influenza virus or derivative thereof requires providing a source of influenza virus or derivative thereof, optionally subjecting the source to a pre-purification step, followed by subjecting the source to at least one chromatographic step on chromatographic material selected from the group consisting of porous particles having mean pore sizes of at least 20 nm, perfusion particles, gel-in-a-shell particles, tentacle like particles, membrane adsorbers, and monoliths, and collecting fractions eluted from the chromatographic material that contain the influenza virus or derivative thereof, excluding sulfuric ester of cellulose or cross-linked polysaccharides.