Fig. 3: Mast cells release IL-17A upon TNF-stimulation and IL-17A promotes neutrophil abluminal migration and final exit.

a Cremaster muscles, ear skin, heart and peritoneal lavage (perito) from WT mice was collected and analyse for IL-17A expression in MCs. Quantification of IL-17A expression by RFI in MCs (n = 5 perito, n = 5 skin, n = 5 heart and n = 4 CM, all p value < 0.0001). b Quantification of IL-17A expression by RFI in MC and macrophages (CD45⁺, CD115⁺) in PBS and TNF treated (4 h) WT mice (n = 4 mice, ***p value < 0.0001, ^##p value = 0.002). c Tissue level of IL-17A analysed by ELISA in PBS and TNF treated (4 h) MC^ctrl or MC^deficent (n = 6 PBS MC^ctrl mice, n = 5 PBS MC^deficient mice, n = 10 TNF MC^ctrl mice and n = 8 TNF MC^deficient mice, **p value = 0.0015, ^###p value < 0.0001, ^##p valu e =0.0018). d Images of the cremasteric microcirculation 4 h post TNF or PBS treatment in WT and IL-17A^KO mice, scale bars 10 µm. e Number of extravascular neutrophils (n = 6 PBS WT mice, n = 5 PBS IL-17A^KO mice, n = 6 TNF WT mice and n = 5 IL-17A^KO mice, ***p value < 0.0001, **p value = 0.002, ^###p value < 0.0001). f Quantification of IL-17RA expression by RFI in indicated cell populations and organs, full gating strategy is shown in Supplementary Fig. 6 (n = 6 mice, all p value < 0.0001). g–k LysM-EGFP-ki; α-SMA-RFPcherry-Tg mice were subjected to TNF (300 ng) induced inflammation for 2 h. Blocking anti-IL-17A mAb (50 µg) or control mAb, was injected i.s. together with TNF. g Number of neutrophil TEM events (n = 5 mice). h Neutrophil abluminal migration distance (n = 28 Ctrl Mab n = 26 anti-IL17A mab neutrophils, p value = 0.010), time (n = 28 neutrophils, p value < 0.0001) and straightness (n = 28 neutrophils, p value = 0.0002); data pooled from five mice. i Number of neutrophil TPM events (p value = 0.0037), j neutrophil TPM hotspots (p value 0.0019) and k number of extravascular neutrophils (p value = 0.0051) (n = 5 mice). Mean ± SEM (each mouse represents one independent experiment). a, f one-way ANOVA followed by Tukey’s post-hoc test; b, c, e two-way ANOVA followed by Sidak’s post-hoc test; g-k two-tailed Student’s t test. *p < 0.05, **p < 0.01, ***p < 0.001 as compared to perito, Mac, MC^ctrl, PBS, ECs or ctrl mAb or as indicated by ^##p < 0.01, ^###p < 0.001 (ns = not significant). Source data are provided as a Source Data file.