Real-time qPCR

Total RNA from cells was obtained using the AxyPrep Multisource Total RNA Miniprep kit (Axygen Scientific, Union City, CA, USA) according to the instructions of the manufacturer. Oligo(dT) primers, 2 µg of total RNA and the Superscript II first-strand synthesis system (Invitrogen) were used to synthesize cDNA. Real-time quantitative PCR (qPCR) was performed using TaqMan assay reagent master mix (Applied Biosystems, Foster City, CA, USA); primers and probes (Assay on Demand mix) for human IFN-β and GAPDH (as endogenous control). Gene expression was determined using and Applied Biosystems 7300 real-time PCR system, all experiments were performed in triplicate, and quantification was done using the comparative threshold cycle (ΔCt) method, as described by the manufacturer (Applied Biosystems). The relative amount of IFN-β mRNA was obtained by normalization to the amount of mRNA of cellular GAPDH, as endogenous control.