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.

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.

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 invention relates to a method for production of continuous cell lines comprising providing living cells of an animal or a human, irradiating said cells with UV light, proliferating said cells and selecting multiplying cells as cells of a continuous cell line.

This disclosure provides a platform for making live, attenuated viruses. This disclosure also provides methods of using the live, attenuated viruses.

The present invention relates to a method for prevention and/or reduction of aggregation of viral components.

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

The present invention relates to the development and manufacturing of viral vaccines. In particular, the invention relates to the field of industrial production of viral vectors and vaccines, more in particular to the use of avian embryonic stem cells, preferably the EBx? cell line derived from duck embryonic stem cells, for the production of viral vectors and viruses. The invention is particularly useful for the industrial production of viral vaccines to prevent viral infection of humans and animals.

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 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.