Targeted Delivery of the HLA-B27-Binding Peptide into the Endoplasmic Reticulum Suppresses the IL-23/IL-17 Axis of Immune Cells in Spondylarthritis

Figure 3

Treatment with either THUA or THUNP increases the antigenic peptide targeted to the cell surface of C1R-B27:04. (a) Treatment with THUA, but not with THU or HUA, increases the HLA-B27:04 HC/β₂m/KRGILTLKY complex presented at the cell surface of C1R-B27:04, as detected by flow cytometry. Knockdown of TAP1 ruins the antigenic peptide, KRGILTLKY, presented on the cell surface. (b) Mean channel fluorescence measured in (a) was averaged from three independent experiments (mean ± SD, ). Values of mean channel fluorescence measured from the large population of C1R-B27:04 cells that display the high levels of HLA-B27:04 on the cell surface were increased when cells were treated with THUA. (c) Treatment with THUNP, but not with THU or HUNP, increases the HLA-B27:04 HC/β₂m/SRYWAIRTR complex presented at the cell surface, as detected by flow cytometry. TAP1 knockdown impairs the antigenic peptide, SRYWAIRTR, presented on the cell surface. (d) Mean channel fluorescence measured in (c) is increased when C1R-B27:04 cells were treated with THUNP. Values (mean ± SD, ) measured from the high population of cells that display the high levels of HLA-B27:04 on the cell surface are averaged from three independent experiments. Statistical significance was obtained by the Mann–Whitney U test.

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