Hrptepic line

The HRPTEpiC line was purchased from ScienCell Research Laboratories (ScienCell, CA, USA), and was maintained in epithelial cell medium (EpiCM, ScienCell Research Laboratories) supplemented with 2% fetal bovine serum (FBS) at 37°C and 5% CO₂. HRPTEpiC were seeded in 24-well plates at a density of 2 × 10⁵ HRPTEpiC/mL. After one day, the medium was replaced with HRPTEpiC culture medium with or without cytokines. HRPTEpiC were stimulated with 1, 10, 50, or 100 ng/mL human recombinant IL-17 (R&D Systems, Inc. Minneapolis, MN) and/or 1, 10, or 50 ng/mL human recombinant TNF-α (R&D Systems) for 72 hours. To examine the immunosuppressive effects of 1,25(OH)₂D3 (Sigma), HRPTEpiC were pre-incubated for 1 hour with 1,25(OH)₂D3 (10 nM), and then stimulated as described above. The in vitro concentrations of 1,25(OH)₂D3 were selected according to the previous studies [15 (link)–17 (link)]. Supernatants were harvested and stored at -80°C until analysis.

The HRPTEpiC line was purchased from ScienCell Research Laboratories. At first, CCR7⁺CD8⁺ T cells were expanded at day 0 as described above. PBMCs (1.5 × 10⁵) were incubated under T-cell activation conditions at day 0 for 72 h. On day 1, HRPTEpiC were seeded in plates. On day 3, isolated and PKH-labeled PBMC cells (1.5 × 10⁵ cells/well) were added with or without expanded and isolated CCR7⁺CD8⁺ T cells (1 × 10⁵ cells or 2 × 10⁵ cells/well). On day 6, the harvested cells were examined for proliferation using a FACSCalibur flow cytometer (BD Biosciences). All cultures were set up in triplicate (Fig. 4a).