Figure 4.

CD1a expression on Langerhans cells is essential for generation of T_H17 cells and dermatitis. (a) Confocal microscopy of epidermal sheets stained for MHC class II and CD1a. Scale bar: 20 μm. (b) Flow cytometry of CD1a expression on CD11c⁺MHCII^hi cells (left panel), CD103 and CD207 (Langerin) expression in CD1a-negative (I, green dots) and CD1a-positive (II, red dots) populations of CD1a-tg mice gated from the left plot (right panel). (c) Flow cytometry of Langerhans cells population in ear cells isolated from mice (n = 3 per group) sensitized to urushiol on day 0 and challenged with vehicle (veh) or urushiol (uru) on day 5, assessed on day 2 after challenge. CD1a expression on CD11c⁺MHCII^int (Gate, G1), CD103⁺CD207⁺ (G2a), and CD103⁻CD207⁺ (G2b) cells among CD11c⁺MHCII^hi (G2) cells of urushiol-challenged mice was further analyzed (far right). (d-g) Ear swelling (d), frequencies of Gr-1^hiCD11b^hi granulocytes (e, top), IL-17A⁺ or IFN-γ⁺ cells among CD45⁺TCRγ⁺CD4⁺cells (e, bottom), absolute cell numbers of CD4⁺ T cells (f, top), IL-17A-producing CD4⁺ T cells (f, bottom), and CD1a expression on LCs in ear skin (g, top) and dLN (g, bottom) from urushiol-challenged wild-type, CD1a-tg, or CD1a-tg mice injected with anti-CD1a or isotype (n = 3 per group). MFI indicate mean fluorescent intensity. Each symbol represents an individual mouse (d,f). Data shown are the mean ± s.e.m. * P < 0.05, ** P < 0.01; NS, not significant, using one-way ANOVA and multiple comparisons. Data are representative of four independent experiments with similar results.