Patent ID: 8815252
Filing Date: 2014-08-26
Classification: A61K,A61P,C12N

Abstract:
1. A cell-culture adapted influenza virus produced by a method comprising the steps of: a) diluting influenza viruses in a solution having a pH of between 5.6 and 5.9; b) infecting host cells in culture with at least one infectious virus particle, wherein: i) the virus particle is added to said cells; and ii) said cells and said virus particle are incubated at a pH of between 5.6 and 5.9 to provide a virus/cell complex; c) cultivating infected host cells to propagate viruses; and d) harvesting the propagated viruses, wherein the virus retains infectivity at a pH range of between 5.6 and 5.8, wherein the influenza virus comprises a deletion or modification within the NS 1 gene of the virus, wherein the propagated viruses do not acquire mutations in the HA molecule when exposed to temperatures of up to 60° C. for 15 minutes, wherein hemagglutination activity of the propagated viruses is decreased less than fourfold compared with the source viruses, and wherein a titer above 7 log TCIDs0/ml is obtained from growth in cultured cells.