Methods of producing influenza vaccine compositions
Methods and compositions for the optimization and production of influenza viruses, e.g., ca influenza B strains, in eggs and host cells suitable as influenza vaccines are provided.
1. A method of increasing the yield of cold adapted reassortant influenza B virus particles, the method comprising:
(a) introducing a plurality of cold adapted reassortant influenza B viruses into SPF embryonated hen eggs;
(b) incubating the host eggs at a temperature of 31±0.5° C.; and,
(c) recovering influenza virus particles from the host eggs,
wherein the recovered virus particles resulting from the incubation has a yield which is greater than the yield resulting from an incubation of said cold adapted reassortant influenza B viruses in host eggs at 33° C.
2. The method of claim 1 , which comprises quantifying the yield by determining the log 10 TCID 50 /mL titer of allantoic fluid of the host eggs infected with the virus particles incubated at 31±0.5° C. and by determining the log 10 TCID 50 /mL titer of allantoic fluid of the host eggs infected with the virus particles incubated at 33° C.
3. The method of claim 2 , wherein the log 10 TCID 50 /mL titer, from the incubation at 31±0.5° C. is from at least about 1.01 to at least about 1.10 times greater than the log 10 TCID 50 /mL titer at 33° C.
4. The method of claim 2 , wherein the log 10 TCID 50 /mL titer, from the incubation at 31±0.5° C., is from at least about 1.025 to at least about 1.05 greater than the log 10 TCID 50 /mL titer at 33° C.
5. The method of claim 2 , wherein the log 10 TCID 50 /mL titer, from the incubation at 31±0.5° C., is from at least about 1.03 to at least about 1.04 times greater, than the log 10 TCID 50 /mL titer at 33° C.
6. The method of claim 1 , wherein said cold adapted reassortant influenza B virus is a 6:2 reassortant.
7. The method of claim 2 , wherein said cold adapted reassortant influenza B virus is a 6:2 reassortant.