Figure 9: CCR6 is important for monocyte trafficking into inflamed skin.

(a) Flow cytometry plots of cells prepared from ears 40 h after monocyte transfers as diagrammed on the left, showing CD45.2⁺ cells from epidermis, and an overlay from the dermis analysed as in Fig. 1e, containing cells that express CD45.1 or CD45.2. (b) Migration of mouse monocytes to medium alone, CCL2 or CCL20. (c) Protocol for monocyte transfers into Ccr6^−/− mice undergoing ear injections with IL-23. (d) Ear thickness for WT and Ccr6^−/− control mice, or Ccr6^−/− mice that had received WT or Ccr6^−/− monocytes either intravenously (IV, top) or into the ears (ID, bottom). (e) Expression of mRNA encoding IL-22 versus Gapdh mRNA in day 6 ears of Ccr6^−/− mice that had received WT or Ccr6^−/− monocytes. (f) Flow cytometry plot (left) of cells prepared from IL-23-injected ears from mice injected with monocytes intravenously per a. Monocytes were a 1:1 mixture of CMTPX-labelled WT cells and CFSE-labelled Ccr6^−/− cells. Numbers indicate percentages of cells within the boxes. Bar graph shows WT (CMTPX⁺) or Ccr6^−/− (CFSE⁺) monocytes per ear. (g) Ratio of WT:Ccr6^−/− blood monocytes and dermal monocytes (T2) and moDDCs (T3+T4) at day 6 in ears injected with IL-23 on day 1, 3 and 5 from mice that had received mixed bone marrow as indicated. The data are from one experiment representative of two with a total of four mice (a); or three experiments with a total of six mice (b); or one experiment representative of two with a total of six mice per group (d; mean±s.d.; pairwise statistical comparisons were done at day 6 using mice from all the experiments); or two experiments with a total of six mice per group (e); or one experiment representative of three (f, left panel); or three experiments with a total of five mice per group (f, right panel); or three experiments with a total of nine and 12 mice used for measurements in blood and dermis, respectively (g). The data are presented as mean±s.e.m. unless otherwise noted. NS, not significant; *P<0.05, **P<0.01, ***P<0.001 (unpaired Student’s t-test).