Figure 4.

Interferon treatment of Ma-Mel-48c cells does not restore HLA class I antigen surface expression. The different Ma-Mel-48 cell lines were treated with IFNα (1000 U/mL) or IFNγ (500 U/mL) for 48 hours, controls were left untreated. A, cells were stained with mAb W6/32 for detection of HLA class I antigen expression. Data from one representative of three independent experiments are depicted, numbers indicate MFI values. B, cell lysates were analyzed by Western blot for the protein levels of interferon pathway components (STAT1, pSTAT1, IRF1) or APM components (HLA heavy chains, tapasin, TAP1, β2m). GAPDH served as loading control. One representative of three independent experiments is depicted. C, mRNA levels of different APM components were quantified by qRT-PCR and normalized to endogenous GAPDH mRNA. Expression levels, given as mean (+SEM) of three independent experiments, are depicted relative to the expression in Ma-Mel-48a cells.