Figure 2.

Sectm1a Deficiency Further Diminishes Tissue-Resident Macrophages in the Spleen and Lung after LPS Injection

The whole spleen and lung tissues were collected from WT and Sectm1a-KO mice at 18 h post-PBS or LPS (10 or 20 μg/g) injection and subjected to flow cytometry analyses. (A) Representative flow cytometry plots of red pulp macrophages (CD45.2⁺ Lin⁻ CD11c⁻ F4/80²⁺ CD11b^low/− cells, blue gate) and splenic monocyte (CD45.2⁺ Lin⁻ CD11c⁻ F4/80⁺ CD11b²⁺ cells, red gate) following PBS or LPS (10 μg/g) treatment. Gating strategy is shown in Figure S3A. (B) Percentages of RPM population in WT and KO spleen were summarized following PBS or LPS treatment (n = 6). (C) The percentage change of the RPM population in the spleen of WT mice in response to different doses (10 μg/g, 20 μg/g) of LPS (n = 8–10). (D) Calculation of the percentage of splenic monocytes in WT and Sectm1a-KO mice after PBS or LPS (10 μg/g) treatment (n = 7–11). (E) Quantification percentages of released monocytes in WT and KO mice with the formula: Percentage of released monocytes = [(percentage of monocytes in PBS group) − (percentage of monocytes remaining in LPS group)]/(percentage of monocytes in PBS group) (n = 11). (F–H) Representative flow cytometry plots of AMs (F) (CD45.2⁺ Ly-6G⁻ CD3⁻ CD19⁻ MerTK⁺ CD64⁺ CD11c⁺ Siglec-F⁺ CD11b⁻) in the lung of WT and Sectm1a-KO mice after PBS or LPS injection. Gating strategy was shown in Figure S3B. Percentages of AMs in total live cells (G) and percentages of AMs in live cells excluding neutrophils (H) were quantified (n = 8). (I and J) Representative flow cytometry plots (I) of inflammatory monocytes (CD45.2⁺ Ly-6G⁻ CD3⁻ CD19⁻ MerTK⁻ Siglec-F⁻ CD64⁺ CD11b⁺ Ly-6C⁺) in the lung following PBS or LPS administration. Percentages of infiltrated inflammatory monocytes in total live cells (J) are shown (n = 5). (K) Flow cytometry showing the infiltration of neutrophil (CD45.2⁺ Ly-6G⁺ CD11b⁺ Ly-6C⁺) in the lung after LPS injection. (L) Percentages of infiltrated neutrophils in total live cells (n = 8).