SKG mice develop interstitial lung disease (ILD) resembling rheumatoid arthritis-associated ILD in humans. The aim of this study was to clarify the mechanism underlying the lung pathology by analyzing lung-infiltrating cells in SKG mice with ILD.
We assessed the severity of zymosan A (ZyA)-induced ILD in SKG mice histologically, and we examined lung-infiltrating cells by flow cytometry. Total lung cells and isolated monocytic myeloid-derived suppressor cells (MDSCs) were cultured in vitro with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4. The proliferation of 5,6-carboxyfluorescein diacetate N-succinimidyl ester-labeled naive T cells cocultured with isolated CD11b+Gr-1
MDSCs, Th17 cells, and group 1 and 3 innate lymphoid cells (ILC1s and ILC3s) were increased in the lungs; the proportion of these cells varied with ILD severity. In this process, we found that a unique cell population, CD11b+Gr-1
We identified unique suppressive myeloid cells that were differentiated from monocytic MDSCs in SKG mice with ILD, and we termed them CD11b+Gr-1