Open AccessGrowth Determinants for H5N1 Influenza Vaccine Seed Viruses in MDCK Cells
Author(s) -
Shin Murakami,
Taisuke Horimoto,
Lê Quynh,
Chairul A. Nidom,
Hualan Chen,
Yukiko Muramoto,
S. Yamada,
Ayaka Iwasa,
Kiyoko IwatsukiHorimoto,
Masayuki Shimojima,
Atsushi Iwata,
Yoshihiro Kawaoka
Publication year - 2008
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.00970-08
Subject(s) - biology , virology , influenza a virus subtype h5n1 , neuraminidase , embryonated , h5n1 genetic structure , virus , hemagglutinin (influenza) , microbiology and biotechnology , antigenic drift , influenza a virus , influenza vaccine , covid-19 , infectious disease (medical specialty) , medicine , disease , pathology
H5N1 influenza A viruses are exacting a growing human toll, with more than 240 fatal cases to date. In the event of an influenza pandemic caused by these viruses, embryonated chicken eggs, which are the approved substrate for human inactivated-vaccine production, will likely be in short supply because chickens will be killed by these viruses or culled to limit the worldwide spread of the infection. The Madin-Darby canine kidney (MDCK) cell line is a promising alternative candidate substrate because it supports efficient growth of influenza viruses compared to other cell lines. Here, we addressed the molecular determinants for growth of an H5N1 vaccine seed virus in MDCK cells, revealing the critical responsibility of the Tyr residue at position 360 of PB2, the considerable requirement for functional balance between hemagglutinin (HA) and neuraminidase (NA), and the partial responsibility of the Glu residue at position 55 of NS1. Based on these findings, we produced a PR8/H5N1 reassortant, optimized for this cell line, that derives all of its genes for its internal proteins from the PR8(UW) strain except for the NS gene, which derives from the PR8(Cambridge) strain; its N1 NA gene, which has a long stalk and derives from an early H5N1 strain; and its HA gene, which has an avirulent-type cleavage site sequence and is derived from a circulating H5N1 virus. Our findings demonstrate the importance and feasibility of a cell culture-based approach to producing seed viruses for inactivated H5N1 vaccines that grow robustly and in a timely, cost-efficient manner as an alternative to egg-based vaccine production.