Anti cxcl9

To determine whether CXCL9 and CXCL10 recruited CXCR3⁺ Tregs, chemotaxis assays were performed. MSC‐treated lungs were lavaged with 2 mL of RPMI 1640 medium supplemented with 10% FBS and penicillin and streptomycin. Then, the resulting BALF was centrifuged and the supernatant was collected and combined. CXCR3⁺ CD4 T‐cell isolation: lungs, mediastinal lymph nodes and spleens were collected from MSC‐treated mice. Single‐cell suspensions were prepared, and T cells were purified by antibody‐coupled magnetic beads. Then, CXCR3⁺ CD4 T cells were sorted out of the purified T cells by a FACSAria. Chemotaxis assay: medium alone and medium containing 200 ng mL⁻¹ of CXCL9 and CXCL10 (Proteintech, Illinois, United States) were used as negative and positive controls, respectively. 200 ng mL⁻¹ of anti‐CXCL9 or 1 μg mL⁻¹ anti‐CXCL10 antibodies (R&D) was added into the lower Transwell chamber (96‐well, Corning, New York, United States) that containing 150 μL of BALF. Then, about 1 × 10⁴ of CXCR3⁺ CD4 T cells were added into the upper Transwell chamber in a total volume of 100 μL. Plates were incubated at 37°C in 5% CO₂ for 2 h. The contents of the lower well were then collected, and cells were counted in a haemacytometer. Cell migration to medium alone was used as control. All assays were performed in triplicate.