Patent ID: 11883483
Assignee: SK BIOSCIENCE CO., LTD.
Field: Pharmaceuticals (Chemistry)
Classification: CPC A  C | IPC A

Claim 10:
11. A method of increasing the infectivity of an influenza working virus seed stock, the method comprising:
a) infecting a cell line adapted to serum-free culture and suspension culture with an influenza vaccine virus such that the infecting is carried out at a plurality of dilution factors, relative to a proportion of the influenza vaccine used to perform the infecting, to obtain a plurality of infected cell lines at different dilution factors;
b) culturing the plurality of infected cell lines, to obtain a plurality of virus cultures at the different dilution factors;
c) measuring cell viability of each of the plurality of virus cultures, and performing a hemagglutination assay (HA) on each of the plurality of virus cultures;
d) selecting one of the plurality of virus cultures as a selected virus culture based on Condition 1 or Condition 2:
Condition 1: if measured HA titers (except for HA titers of 0) of at least two of the plurality of virus cultures are different by a factor of 4 times or more, then the selected virus culture is a virus culture with a dilution factor having a highest measured HA titer, or
Condition 2: if Condition 1 is not satisfied, then the selected virus culture is a virus culture with a dilution factor having a highest measured cell viability; and
e) further passaging the selected virus culture in the same cell line to prepare an influenza working virus seed stock at least once.