The present invention provides cells which have a high ability to propagate influenza virus, are suitable for use in production of an influenza virus for preparing a vaccine, and are able to be cultured in vitro, and a method for producing an influenza virus using the cells. That is, the present invention provides cells for producing an influenza virus in which expression of one or more genes that encode proteins involved in an effect of suppressing influenza virus production in a cell is suppressed and the gene is at least one selected from the group including ACTG1 gene and the like, and a method for producing an influenza virus that includes infecting the cells for producing an influenza virus with an influenza virus and then culturing.

The invention provides a composition useful to prepare influenza viruses, e.g., in the absence of helper virus, using vectors which include tandem transcription cassettes containing PolI and/or PolII promoters.

The present invention relates to modified avian eggs which can be used to produce increased levels of virus. The present invention also relates to methods of producing viruses in avian eggs of the invention, as well as the use of the viruses obtained to prepare vaccine compositions.

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.

The present invention relates to a sulfated cellulose hydrate membrane, a method for the preparation thereof and the use of the membrane as adsorption membrane for the purification of viruses.

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.

The invention provides a composition useful to prepare high titer influenza viruses, e.g., in the absence of helper virus, which includes at least five internal genes from an influenza virus isolate that replicates to high titers in embryonated chicken eggs or MDCK cells.

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.

The present invention relates to methods of replicating viruses in vitro. In particular, the invention relates to a genetically modified population of cells, and/or a population of cells treated with an exogenous compound, wherein the cells are capable of producing more virus than cells lacking the genetic modification and/or lacking treatment with the exogenous compound. The invention also relates to methods of producing populations of such cells, as well as the use of the viruses obtained to prepare vaccine compositions.

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.