Abstract: Viruses from the family Orthomyxoviridae, particularly influenza virus, can grown in monkey kidney cells, particularly Vero Cells, after passaging the cells in a serum-free or protein-free medium. The use of a proteolytic enzyme, especially trypsin, also aids in the propagation of the virus. The method allows for the virus to be produced to be used in a vaccine.

Abstract: The invention relates to a method of inactivating lipid-enveloped viruses by means of a non-ionic detergent, and the preparation of a vaccine containing the inactivated virus. The invention further relates to an inactivated virus which is characterized by its structural integrity, in particular the structural integrity of its enveloping proteins, as well as to the use of the inactivated virus for preparing a vaccine.

Abstract: A method for producing Influenza and other viruses and vaccines derived therefrom utilizes serum-free cultured vertebrate cells or vertebrate biomass aggregates to both eliminate the necessity to use costly methods requiring whole chicken embryos and, optionally, to provide proteases suitable for the activation of a wide variety of viruses. In one aspect, the method comprises the periodic or continuous removal of "treatment portions" of virus-containing culture medium into an "augmentation loop" for treatment with a broad range of substances, such as proteases that augment the activation of the virus. Use of the loop allows utilization of such substances at high concentrations while eliminating their cell toxic effects. Another aspect of the invention provides for the alteration of cleavage sites in virus proteins to thereby render them more susceptible to activation in culture.

Abstract: A method for producing Influenza and other viruses and vaccines derived therefrom utilizes serum-free cultured vertebrate cells or vertebrate biomass aggregates to both eliminate the necessity to use costly methods requiring whole chicken embryos and, optionally, to provide proteases suitable for the activation of a wide variety of viruses. In one aspect, the method comprises the periodic or continuous removal of "treatment portions" of virus-containing culture medium into an "augmentation loop" for treatment with a broad range of substances, such as proteases that augment the activation of the virus. Use of the loop allows utilization of such substances at high concentrations while eliminating their cell toxic effects. Another aspect of the invention provides for the alteration of cleavage sites in virus proteins to thereby render them more susceptible to activation in culture.

Abstract: A method of producing an influenza virus and vaccines derived from the virus utilizes cultured vertebrate biomass aggregates comprising a plurality of cell types derived from a plurality of vertebrate tissues and is particularly suitable for use with chicken embryo cultures. The method both eliminates the necessity to use costly methods requiring whole chicken embryos and provides proteases suitable for the activation of a wide variety of viruses. After infecting the cells of the culture with an influenza virus, which is preferably modified to create a cleavage site in the hemagglutinin of the virus, a substance such as a protease is introduced that cleaves the hemagglutinin. The culture then is incubated under conditions that permit growth of the virus.