Induction of TNF-alpha in human macrophages by avian and human influenza viruses.
The highly pathogenic avian influenza virus H5N1 is known to induce high level of tumor necrosis factor alpha (TNF-alpha) from primary macrophages. However, it is still unclear whether current H5N1 strains also induce high TNF-alpha production, as most of the data were derived from extinct clade 0 H5N1 strain. Here, we show that current clade 1 and 2 H5N1 strains induce variable levels of TNF-alpha that are not necessarily higher than those induced by seasonal influenza viruses. The result suggests that hyper-induction of TNF-alpha in human macrophages is not always associated with a highly pathogenic phenotype. We further tested the contribution of the NS gene segment from H5N1 isolates to TNF-alpha induction by using reverse genetics. While NS conferred some variation in TNF-alpha induction when incorporated into an H1N1 virus genetic background, it did not affect TNF-alpha induction in an H5N1 virus genetic background, suggesting that other viral genes are involved.
Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
Yuwarat
Y
Monteerarat
Saori
S
Sakabe
Somying
S
Ngamurulert
Sirawat
S
Srichatraphimuk
Wasana
W
Jiamtom
Kridsada
K
Chaichuen
Arunee
A
Thitithanyanont
Parichart
P
Permpikul
Taweesak
T
Songserm
Pilaipan
P
Puthavathana
Chairul A
CA
Nidom
Le Quynh
le Q
Mai
Kiyoko
K
Iwatsuki-Horimoto
Yoshihiro
Y
Kawaoka
Prasert
P
Auewarakul
D000818:Animals; D001717:Birds / Q000821:virology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology; D009980:Influenza A virus / Q000276:immunology*; D005585:Influenza in Birds / Q000821:virology*; D007251:Influenza, Human / Q000821:virology*; D008264:Macrophages / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D017361:Viral Nonstructural Proteins / Q000276:immunology
C108309:NS protein, influenza virus; D014409:Tumor Necrosis Factor-alpha; D017361:Viral Nonstructural Proteins