Inhibition of HAZV replication with siS1 or siS2 in A549 cells. A) Cells were transfected with 100 nM of siS1 or siS2 and then infected with HAZV at different MOI (i.e. 0.01, 0.1 and 1). B) and C) 24 hrs before HAZV infection (at a MOI of 0.1) cells were transfected with different concentrations of siS1 or siS2 (from 0.01 to 100 nM). Viral titers were determined 48 hrs post-infection. Results are presented as a ratio between the average foci counts from siRNAs treated wells and counts in siNT (siRNA negative control) transfected cells. Errors bars represent the standard deviation (SD) of the means for at least two independent experiments carried out in quadruplicates. * Significant differences compared to the siNT control: Student's t-test; P < 0.05. D) Lysates from A549 cells infected with HAZV and treated with different concentrations of siS2 (or 100 nM of siNT or siM4) were loaded on a 10% SDS-PAGE and electrotransferred on a PVDF membrane. Expression of the ~ 50 kDa NP was detected with an anti-HAZV ascite (GAPDH expression was used as loading control).