Quantitative analysis of IFN-alpha up regulated genes and proteins involved in antigen presentation pathways. Validation of differential expression of PSMB8 (A), DTX3L (B) and FBOX6 (C) in RPTEC stimulated with IFN-alpha. Expression levels were quantified using RT-PCR. The genes’ relative expressions were normalized to the expression of ß actin. The histograms represent the mean ± SEM. The intracellular expression of LMP7 was evaluated by flow cytometry analysis (D) (LMP7 48.09% ± 2 basal versus 76.18% ± 2, 48 hours, 100 U/ml INF-alpha) and western blot analysis (LMP7 basal versus 48 hours, 100 U/ml INF-alpha P <0.02) (E). The surface expression of HLA I (F) in RPTEC stimulated with IFN-alpha showed a significant increase of mean fluorescence intensity (MnI) (19.5 ± 3 basal versus 43.7 ± 2, 48 hours, 100 U/ml IFN-alpha stimulation). Data shown were gated on RPTEC cells and histograms were based on RPTEC staining with isotype control mAbs. The data presented for both HLA-I and LMP7 are representative of three independent experiments performed using RPTEC cells (P <0.02 and P <0.05, respectively). mAbs, monoclonal antibodies; RPTEC, renal proximal tubular cells; SEM, standard error of the mean.