Figure 2.

Infiltration of myeloid-derived suppressor cells (MDSCs) expressing CXCR2 into the lung in bleomycin treated mice with macrophage depletion. (A) Representative flow plot, where CD11b⁺Ly6C^hiLy6G^- cells (highlighted in blue) represent monocytic MDSCs (Mo-MDSCs), and CD11b⁺Ly6C^loLy6G⁺ cells (highlighted in orange) represent granulocytic MDSCs (G-MDSCs). Gated on live singlet CD45⁺ cells. (B) The absolute cell numbers of CD11b⁺ cells, determined based on lung cellularity. (C) The absolute cell numbers of Mo-MDSC and G-MDSC of CD11b⁺ cells based on lung cellularity. (D) The percentage CXCR2⁺ cells of Mo-MDSC or G-MDSC cell population. (E) Percent arginase (Arg) 1⁺ inducible nitric oxide synthase (iNOS)⁺ cells in Mo-MDSCs and G-MDSCs. (F) Whole-lung Arg activity of liposome-treated wild-type mice (n = 12 per group over course of three independent experiments). (G) CD11b⁺Gr-1⁺ cells were purified from the spleens of bleomycin- and liposome-treated mice and placed in a suppression assay with purified carboxyfluorescein succinimidyl ester–stained C57BL/6 T cells at the designated ratios. Anti-CD3/CD28 beads were used to induce proliferation. Cells were harvested on Day 5 and analyzed by flow cytometry for dilution (n = 8 per mouse group experiment). Results are plotted as the mean (±SEM). *P < 0.05. Ly6 = lymphocyte antigen 6 complex.