Fig. 3

Knockdown of galectin-3 decreases viral production in IAV-infected A549 cells. a Examination (left) and quantitation (right) of the knockdown efficiency of different shRNAs specific to human galectin-3. b Quantification of galectin-3 in the conditioned medium of galectin-3-knockdown and vector control A549 cells infected with IAV by ELISA (n = 3). c Detection (left) and quantitation (right) of the viral NS1 protein in different galectin-3-knockdown and control cells following IAV infection. Values shown are mean ± SD (n = 3–4). d Quantification of viral titers in galectin-3-knockdown and control cells infected with IAV for 24 and 48 h by the plaque assay (n = 3). A549 cells were transduced with lentiviral vectors encoding different shRNAs specific to galectin-3 or LacZ to generate stable knockdown cell clones and then infected with Influenza A/WSN/33 (H1N1) viruses at MOI of 1 for 7 h (a, c) and 0.01 for 24 and 48 h (d). Levels of galectin-3 (a) and viral NS1 proteins (c) were examined by immunoblotting. Expression of β-actin served as the loading control. e Detection (left) and quantitation (right) of the viral NS1 protein in galectin-3-overexpressing and control A549 cells after infection with IAV. Cells that had been transfected with the Flag-tagged galectin-3 expression vector, the control vector, or left untransfected were infected with IAV at an MOI of 1 for 7 h and then examined for viral NS1 and galectin-3 proteins by immunoblotting. Expression of β-actin served as the loading control. f Detection (left) and quantitation (right) of the viral NS1 protein in galectin-3-knockdown and control A549 cells after infection with influenza A/PR/8/34 (H1N1) viruses at an MOI of 1 for 7 h. Expression of β-actin served as the loading control. Values shown are mean ± SD (n = 3). Ratios of shLacZ control cells (a, c, f) and IAV-infected mock cells (e) were arbitrarily set to 1