Enhanced expression of an alpha2,6-linked sialic acid on MDCK cells improves isolation of human influenza viruses and evaluation of their sensitivity to a neuraminidase inhibitor.
The extensive use of neuraminidase (NA) inhibitors to treat influenza virus infections mandates close monitoring for resistant variants. Cultured cells do not provide a reliable means of evaluating the susceptibility of human influenza virus isolates to NA inhibitors. That is, the growth of such viruses in cell lines (e.g., Madin-Darby canine kidney [MDCK] cells) is not inhibited by these drugs, even though their sialidase activity is drug-sensitive. Matrosovich et al. (J. Virol. 77:8418-8425, 2003) showed that an MDCK cell line overexpressing the human beta-galactoside alpha2,6-sialyltransferase I (ST6Gal I) gene has the potential to assess the sensitivity of human influenza virus isolates to NA inhibitors, based on studies with a limited number of viruses. Here, we asked whether clinical isolates of influenza virus are universally sensitive to an NA inhibitor (oseltamivir) in an MDCK cell line expressing the ST6Gal I gene. The sensitivity of viruses to oseltamivir correlated with the sensitivity of viral sialidase to the compound, demonstrating the potential utility of this modified cell line for detecting NA inhibitor-resistant viruses. Moreover, in ST6Gal I-overexpressing cells, the growth of human influenza viruses was up to 2 logs higher than in MDCK cells. We conclude that the human ST6Gal I-expressing MDCK cell line is useful not only for evaluating their sensitivity to NA inhibitors, but also for isolation of influenza viruses from clinical samples.
Hatakeyama
Shuji
S
Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Sakai-Tagawa
Yuko
Y
Kiso
Maki
M
Goto
Hideo
H
Kawakami
Chiharu
C
Mitamura
Keiko
K
Sugaya
Norio
N
Suzuki
Yasuo
Y
Kawaoka
Yoshihiro
Y
D000081:Acetamides / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D009975:Orthomyxoviridae / Q000187:drug effects* / Q000302:isolation & purification*; D053139:Oseltamivir
D000081:Acetamides; D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D053139:Oseltamivir; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid