Expression of the molecules involved in MHC class I–restricted antigen presentation is modulated by TNF-α.
Total lysates of 105 cells untreated or treated with TNF-α were subjected to Western blot analysis and visualized by enhanced chemiluminescence. Specific antibodies used were directed to TAP1, TAP2, LMP2, LMP7, MECL-1, PA28α, and MHC class I heavy chain (HC). LCL, which has a phenotype of activated B cells, was used as a positive control, and T2, which has a homozygous deletion in the MHC region including both LMPs and TAPs as a negative control for catalytic subunits of the immunoproteasome and TAP1/TAP2 expression. To confirm equal protein loading in the samples, actin-specific antibodies were used for each Western blot procedure. Three to 4 independent experiments were performed for each cell line. Results of one representative experiment are shown.
