Method for propagating influenza virus

1. A method for propagating influenza virus which comprises:

(a) culturing influenza virus-sensitive cells selected from the group consisting of MDCK cells, Vero cells, EBx cells, PER.C6 cells and SK-NEP-1 cells in a serum-free medium;

(b) removing a trypsin inhibitor secreted into the serum-free culture medium of the influenza virus-sensitive cells by washing with a serum-free medium or a buffer; and

(c) inoculating influenza virus into said influenza virus-sensitive cells and culturing said influenza virus-inoculated cells.

2. The method of claim 1 , wherein influenza virus-inoculated cells are cultured in a serum-free medium containing trypsin at 0.45 to 2.7 U/mL.

3. The method of claim 1 , wherein said method comprises steps (1) to (5) as follows:

(1) subjecting a cell culture of influenza virus-sensitive cells in serum-free medium to centrifugation at a low speed or to membrane filtration to isolate cells from the culture supernatant;

(2) washing the cells with a serum-free medium or a buffer to remove a trypsin inhibitor secreted into the culture of the influenza virus-sensitive cells;

(3) inoculating influenza virus into the influenza virus-sensitive cells;

(4) culturing the influenza virus-inoculated cells; and

(5) adding a trypsin solution at a final concentration of trypsin of 0.45 to 2.7 U/mL while culturing said influenza virus-inoculated cells.

4. The method of claim 1 , wherein m.o.i, of influenza virus is 0.0001 to 0.01 and a cell density of said influenza virus-inoculated cells is 3-11×10 6 cells/mL.

5. The method of claim 1 , wherein said influenza virus-inoculated cells are cultured in suspension culture.