Fig 2: Normal hapten-specific LN cell responses in Il31-/- mice. (a) LN cells from FITC-sensitized wild-type (n = 5) and Il31-/- (n = 5) mice were cultured in the presence and absence of 40 µg/ml FITC for 48 and 72 hours. The levels of IFN-?, IL-4 and IL-17 in the culture supernatants were determined by ELISA. The data show the mean + SEM.

Fig 3: Generation of Il31-/- mice. (a) IL-31 gene targeting strategy. The region containing a part of exon 2 and exon 3 of Il31 was replaced with a cassette consisting of IRES-EGFP and a neomycin resistance gene (Neor), flanked by loxP sequences. (b) Expression of Il31 mRNA in lung tissue from wild-type (n = 8) and Il31-/- (n = 8) mice by qPCR. The data show the mean + SEM. (c) Leukocyte profiles in the spleen from wild-type and Il31-/- mice (n = 3). The percentages of CD19+ CD3- and CD19- CD3+ cells and of Gr1+ Siglec F- and Gr1- Siglec F+ cells in 7-AAD-negative spleen cells, and the percentages of CD8+ CD4- and CD8- CD4+ cells in 7-AAD-negative CD3+ spleen cells are shown. Representative flow cytometry data are shown.

Fig 4: Normal skin DC function in Il31-/- mice. (a) The proportion of FITC-positive cells among 7-AAD-negative MHC class IIhi CD11c+ cells in draining LNs from wild-type (n = 4) and Il31-/- (n = 4) mice 24 hours after sensitization with FITC or vehicle alone was determined by flow cytometry. Representative flow cytometric data are shown. Shaded areas = LNs obtained from the vehicle-treated left ear (lower number [%]), and solid lines = LNs obtained from the FITC-treated right ear (upper number [%]). The data show the mean + SEM. (b) The expression levels of CD86, CD40 and OX40L on 7-AAD-negative MHC class IIhi CD11c+ FITC-positive cells in draining LNs from wild-type and Il31-/- mice 24 hours after sensitization with FITC or vehicle alone were determined by flow cytometry. Representative flow cytometric data are shown for wild-type (n = 6) and Il31-/- (n = 4) mice. Shaded areas = isotype-matched control Ig staining, and solid lines = specific mAb staining.

Fig 5: IL-31 is important for pruritus, but not skin inflammation, during DNFB-induced CHS. (a) Wild-type (n = 12) and Il31−/− (n = 12) mice were epicutaneously sensitized and challenged with DNFB. The ear skin thickness of the mice was measured at the indicated time points after challenge with DNFB or vehicle alone. The data show the mean + SEM. (b) Scratching behavior (number of times and duration) in wild-type (WT; n = 8–13) and Il31−/− (n = 8–12) mice was assessed at 24 and 48 hours after challenge with DNFB or vehicle alone. The data show the mean + SEM. *p < 0.05 and **p < 0.01.