Freshly γδ T cell-depleted mice develop less severe IMQ-induced psoriasis. (A–C) IMQ-induced psoriasis. Ears of indicated genotypes were treated with IMQ or Vaseline (Vas.), starting at day 3 after γδ T cell depletion (DTx). (A) Ear skin immunofluorescence histology at day 8 of IMQ treatment of mice shown in B, CD3⁺ T cells (blue), and CD11b⁺Ly6G⁺ neutrophils (yellow). Bars, 100 µm. Representative images from of two independent experiments with n = 1–4 mice each. (B) Change of ear thickness given as percent diameter of untreated ears (day 0; left) and disease score (right) over time. Graphs show pooled data from three experiments, each one to four mice per group (total numbers of mice: seven Tcrd-GDL DTx IMQ; eight Tcrd-GDL ctrl. IMQ; seven Tcrd^−/− IMQ; six Tcrd-GDL DTx Vas; five Tcrd-GDL ctrl. Vas; six Tcrd^−/− Vas); two-way ANOVA with Bonferroni posttests, mean ± SD. (C) Epidermal hyperplasia measured on H&E-stained ear skin sections of IMQ- and Vaseline-treated ears of the indicated genotypes, respectively. Scatter plot shows quantification of the epidermal thickening measured on the sections; each dot represents one measurement acquired on 36 slides of two mice per group (left). Representative images out of two mice per group. Bars, 50 µm (right). Data were validated in two independent experiments. (D) Steady state mean frequency of IL-17A–producing CD45⁺ lymphocytes in ear skin of control (ctrl.) and γδ T cell–depleted Tcrd-GDL mice, day 3 (d3) after depletion, compared with Tcrd^−/− mice by intracellular flow cytometry. Pooled data from three to five experiments with each n = 2–4 mice per group; one dot equals one mouse, mean. One-way ANOVA with Bonferroni posttests. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant.