Fig. 3.

Soluble SIGLEC5 impairs CD8⁺T cell proliferation. (a) Proliferation levels (percentage of CFSE^dim cells) (left panel) and linear regression (right panel) of PWD-stimulated CD4⁺ (orange) and CD8⁺ (mocha) cells from HVs in presence of different concentrations of human recombinant sSIGLEC5r for 5 days (n = 5). (b) Representative histograms overlays of the proliferating CFSE^dim PWD-stimulated CD4⁺ (left panel) and CD8⁺ (right panel) cells from HVs in presence (filled line) or not (clear line) of human sSIGLEC5r for 5 days. (c) Proliferation levels (percentage of CFSE^dim cells) of PWD-stimulated CD4⁺ (orange) and CD8⁺ (mocha) T cells from HVs in presence or not of the highest concentration of sSIGLEC5r used (1000 ng/mL) for 5 days (n = 5). (d) Percentage of apoptotic (PI^–/AnnexinV⁺) CD8⁺ T cells isolated from HV and incubated (filled column) or not (clear column) with sSIGLEC5r for 24 h at 500 and 1000 ng/mL (n = 5). (e) Soluble SIGLEC5 (sSIGLEC5) levels in supernatants of monocytes (n = 14) and neutrophils (n = 6) treated (grey filled column) or not (white column) with 10 ng/mL of LPS for 16 h. (f) Representative histogram overlay of SIGLEC5 expression on LPS-stimulated CD14⁺ cells in absence (grey filled) or presence (wine filled) of a pan-inhibitor of metalloproteinases (GM6001) added 6 h before the LPS stimulation for 16 h. (g) MFI of SIGLEC5 on CD14⁺ cells from HVs exposed to LPS (grey), GM6001 (orange), and combinations (wine) for the indicated times (n = 3). (h) sSIGLEC5 levels in the supernatants of monocytes from HVs exposed to LPS (grey), GM6001 (orange) and combinations (wine) for indicated times (n = 3). A control without any stimulation is represented in white. Data shown as mean ± SEM. (a, left panel) Two-way ANOVA test (∗∗p < 0.01). (a, right panel) Spearman linear regression test (∗p < 0.05). (c–e) Paired t-test (∗p < 0.05; ∗∗p < 0.01). (g and h) One-way ANOVA test (∗∗p < 0.01; ∗∗∗p < 0.001).