Figure 4.

Comparison of pulmonary immune cell numbers obtained by flow cytometry following exposure to OPP^2.5 particles (80 µg), PPP^2.5 particles (80 µg) or vehicle (50 µl sterile saline). (A) Fluorescence-activated cell sorting gating strategy used to identify pulmonary major immune cells. Live CD45⁺ cells were gated and myeloid cells were gated on CD11c vs. CD11b. Total myeloid cells were then plotted as MerTK vs. CD64 and the MerTK⁺ CD64⁺ macrophage gate was plotted as CD11c vs. MHC II to illustrate the AMs and IM1, IM2 and IM3. A macrophage-deficient gate was plotted with CD11c and MHC II to illustrate DCs, which were plotted as CD11c vs. CD11b to identify Batf3⁺ and Irf4⁺ DCs. A macrophage/DC-deficient gate was plotted as Ly6G vs. CD11b to identify neutrophils (CD11b⁺ Ly6G⁺) and a macrophage/DC/neutrophil-deficient gate was plotted as SSC vs. F4/80 to identify eosinophils and monocytes. (B) The proportion of CD45⁺ cells in living cells and the absolute number of CD45⁺ cells in each sample from treated and control groups. The proportion of (C) AMs, (D) IM1s, (E) neutrophils, (F) DCs, (G) Batf3⁺, (H) Irf4⁺ and (I) monocytes in CD45⁺ cells and their absolute number. The circles represent the corresponding data of each mouse in the control group, the squares represent the corresponding data of each mouse in the OPP^2.5 group, and the triangles represent the corresponding data of each mouse in the PPP^2.5 group. Data are presented as mean ± standard error of the mean (n=4/group). ^*P<0.05 and ^**P<0.01 vs. control. ^#P<0.05 and ^##P<0.01 vs. OPP^2.5 group. OPP^2.5, original atmospheric particulate matter with a diameter ≤2.5 µm; PPP^2.5, pure atmospheric particulate matter with a diameter ≤2.5 µm; CD, cluster of differentiation; MHC, major histocompatibility complex; AMs, alveolar macrophages; IM, interstitial macrophage; DC, dendritic cell; SSC, side scatter.