Induction of interferon stimulated genes by IL-28A in GSB1 cells. GSB1 cells were treated by either control or 2-ml IL-28A-conditioned medium for 12 hours. Total RNA was isolated, followed by RT-PCR analysis using a pair of gene-specific primers and a pair of DADPH primers. The PCR amplification cycle is 25, which ensures PCR reaction in linear range. The PCR products were analyzed in 1% agarose gel. M indicates the DNA molecular weight marker. The arrow indicates gene-specific products. The bar indicates GADPH DNA fragment. The figure is a representative of two independent assays.