Activation of the Innate Immune Checkpoint CLEC5A on Myeloid Cells in the Absence of Danger Signals Modulates Macrophages’ Function but Does Not Trigger the Adaptive T Cell Immune Response

Figure 4

CLEC5A expression is elevated on proinflammatory M1 MdM while minimal on tumor-associated macrophages. (a) Human monocytes from 3 healthy donors were terminally differentiated into several subsets of monocyte-derived macrophages (MdM): M1, M0, M2c, and TAM. cells in 100 μL/well were FACS stained with a PE-labelled α-CLEC5A Ab (1 : 40, grey line) or with isotype ctrl (1 : 40, grey shadow). Histograms show representative stainings from one of three donors per condition. (b) Macrophages isolated from the ascites fluid collected from three patients with advanced ovarian carcinoma were FACS stained at 10⁵ cells in 100 μL/well with a PE-labelled α-CLEC5A Ab (1 : 40, grey line) or with isotype ctrl (1 : 40, grey shadow). Data represent three individual donors tested in technical duplicates. The CLEC5A expression is shown as an antibody vs isotype histogram overlay (upper panel) or as median fluorescence intensity (MFI) of the CLEC5A Ab staining or isotype ctrl for each group tested (lower panel). Values represent the mean and SD of each donor; , , and .

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