Fig 6.

SOCS3 overexpression in human macrophages reduced USSR H1N1-induced TNF-α production. (A) Human macrophages were transfected with a SOCS3 expression plasmid (pCMV-SOCS3 from Addgene) and a GFP control vector (at a ∼50% transfection efficiency by electroporation) (i); at 48 h posttransfection, cells were infected with USSR H1N1 virus for 24 h at an MOI of 1.0. Antibody detection of virus nucleoprotein showed a similar presence of the protein in SOCS3-overexpressed (ii) and control (iii) macrophages. A significantly lower influenza virus M gene RNA level was detected in culture supernatants from SOC3-overexpressed macrophages than in GFP-transfected macrophages (iv). Scale bars, 100 μm. (B) The TNF-α mRNA expression level in USSR H1N1 virus-infected SOCS3-overexpressed macrophages was significantly reduced in relation to levels in the infected control. (C) Likewise, the corresponding induction of the TNF-α protein by USSR H1N1 virus was significantly reduced in SOCS3-overexpressed macrophages. *, P < 0.05.