Timely production of A/Fujian-like influenza vaccine matching the 2003-2004 epidemic strain may have been possible using Madin-Darby canine kidney cells.

Timely production and antigenic match with those of the epidemic strains are required for influenza vaccines. A/Fujian/411/2002-like (H3N2) virus was the main epidemic influenza virus during the 2003/2004 season in the northern hemisphere. But A/Fujian-like reassortant viruses were not available until more than one year later. We evaluated the A/Kumamoto/102/2002 strain, an A/Fujian/411/2002-like strain isolated in 2002, as a potential vaccine. We compared A/Kumamoto/102/2002 viruses isolated from the same clinical sample in Madin-Darby canine kidney (MDCK) cells and eggs. Kumamoto/102/2002 isolated from eggs grew poorly and showed amino acid mutations of haemagglutinin. In contrast, A/Kumamoto/102/2002 isolated from MDCK cells grew well in MDCK suspension culture. The amino acid sequence of MDCK-derived A/Kumamoto virus was identical to that of A/Fujian/411/2002. These results suggest that culture in MDCK cells could have produced an influenza vaccine with a better antigenetic match to the predicted epidemic strain for the 2003/2004 season than the vaccine actually produced.