Institute of Experimental Medicine, S.-Petersburg, Russia
Reassortant strains for modern live influenza vaccines are prepared using growing chicken embryos. It is very important to switch manufacture of influenza vaccines from chicken embryos to cell cultures, especially due to the threat of future pandemic, when there will be need of big quantities of vaccine for immunization of all age groups. Efficacy of production of reassortant strains with 6:2 vaccine formulation of genome (6 internal genes from the donor of attenuation and 2 genes coding external antigens – hemagglutinin and neuraminidase — from epidemic strain) in MDCK cell culture, using standard techniques employed for production of the vaccine in chicken em-bryos, was studied. It was shown that yield frequency of aforementioned reassortants of influenza A viruses did not exceed 5,7% whereas in chicken embryos vaccine 6:2 reassortants were isolated with frequency of 4%. For influenza B viruses, yield of 6:2 reassortants in growing chicken embryos exceeded 67% whereas in MDCK cell culture we were unable to produce clones with required genome composition. Thus, existing method while effec-tive for production of vaccine reassortants in chicken embryos is low effective for isolation of 6:2 reassortants in MDCK cell culture. Fundamentally new techniques are needed for production of reassortant strains for live influ-enza vaccine in cell culture.
Zh. Mikrobiol. (Moscow), 2007, No. 6, P. 40—45