Fig. 8

Granulocyte infiltration and cytokine upregulation in response to Culicoides sonorensis midge feeding is mast cell dependent. Micro-thin cross abdominal skin sections from (a) 10-week-old wild type mast cell-sufficient (WBB6F1-^+/+) mice, (b) CTMC-reconstituted (WBB6F1-^W/Wv -R) mice or (c) mast cell-deficient (WBB6F1-^W/Wv) mice at 3 h post-feeding (hpf) by C. sonorensis stained for chloroacetate esterase activity indicative of activated granulocytes. Insets show degranulating mast cells. Arrows showing infiltrating granulocytes, primarily of neutrophil lineage, were abundant in abdominal areas associated with midge feeding in wild type and mast cell-reconstituted mice. (Magnifications: 1000×, scale-bars: 10 μm). d Quantitative RT-PCR measuring cytokine expression in inguinal lymph node cells of mast cell-deficient (W/Wv), mast cell-sufficient (+/+), and CTMC-reconstituted (W/Wv-R) mouse strains at 3 hpf. Increased expression levels (y-axis) are reported as a corrected fold difference (2^-ΔΔC_T) compared to naïve controls (basal level). Beta actin was used as an internal control. Additionally, wild type (+/+) and reconstituted (W/Wv-R) groups were compared to the mast cell-deficient (W/Wv) group (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; Holm-Sidak t-test for multiple comparisons between the groups within each cytokine)