Effect of BXL-01-0029 on IFNγ+TNFα-induced class I and class II HLA in Hfsmc.

A, Immunocytochemistry revealed no constitutive expression of class I and class II HLA in control Hfsmc (left A); positive staining for both antigens was observed after 24–48 h incubation with IFNγ+TNFα (middle A); BXL-01-0029 significantly counteracted cytokine-induced class II HLA expression at both time points, with no effect onto class I HLA (right A). Pictures are representative. B, C, Cells were scored as either positive or negative for class I and class II HLA, respectively. Stained cells for each antigen were virtually absent in control cells (class I HLA: 2.3±0.19% and 0.5±0.3% for class I and II HLA, respectively). Stimulation with IFNγ+TNFα induced virtually all Hfsmc to express class I HLA (98.8±0.8% at 24 h; 99.1±0.9 at 48 h, **P<0.01 vs. control) and about half of the cells to express class II HLA (50.75±6.86% at 24 h; 54.96±2.21% at 48 h, **P<0.01 vs. control). The simultaneous incubation with BXL-01-0029 significantly decreased the number of class II HLA-stained cells after 24 h (27.51±5.81%, #P<0.05 vs. cytokine-treated cells) and 48 h (23.54±3.31%, ##P<0.01 vs. cytokine-treated cells). Results are obtained with four different cell preparations and expressed as the percentage of positive cells over the total (mean±S.E.).