Transcription level (A) and cell surface expression (B) of HLA-ABC molecules in ESTDAB-004 and ESTDAB-159 melanoma cell lines [in (B) examined by indirect immunofluorescence using W6/32 and L-362 mAb]. Cells were treated with 800 U/ml of either IFN-γ or IFN-α for 48 h or with culture medium alone. The dark histogram corresponds to the isotypic control. Panel A – the results of real-time RT-PCR analysis. On the Y-axis on panel A – mRNA copy number of the gene of interest (HLA-A or HLA-B) normalized against the mRNA copy number of the reference gene GUSB.