Interleukin-17 is Produced by Both Th1 and Th2 Lymphocytes, and Modulates Interferon-γ- and Interleukin-4-Induced Activation of Human Keratinocytes  Cristina Albanesi, Claudia Scarponi, Andrea Cavani, Monica Federici, Francesca Nasorri, Giampiero Girolomoni  Journal of Investigative Dermatology  Volume 115, Issue 1, Pages 81-87 (July 2000) DOI: 10.1046/j.1523-1747.2000.00041.x Copyright © 2000 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 1 Th0, Th1, and Th2 nickel-specific clones release IL-17. Nickel-specific CD4+ T cell clones were prepared from peripheral blood and patch test reactions of nickel-allergic patients. ELISA for IL-17 was performed on the supernatants of 36 Th0, 30 Th1, and 14 Th2 nickel-specific T cell clones after 48 h activation with plate-coated anti-CD3 and soluble anti-CD28 MoAb. About 50% of Th0, Th1, and Th2 clones released more than 50 pg per ml of IL-17; 20% of the clones released a low amount (10–50 pg per ml); and 30% showed an IL-17 production of less than 10 pg per ml. Data are expressed as picograms per 106 cells per ml. Journal of Investigative Dermatology 2000 115, 81-87DOI: (10.1046/j.1523-1747.2000.00041.x) Copyright © 2000 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 2 IL-17 directly, and together with IFN-γ and IL-4, diminishes the ratios of IL-1ra to IL-1α in keratinocyte supernatants and lysates. IL-1α and IL-1ra extracellular and intracellular quantitations were performed by ELISA on supernatants (a and b) and lysates (d and e) collected from the same keratinocyte culture after 48 h treatment with medium alone or in the presence of 100 U of IFN-γ per ml, 50 ng IL-17 per ml, 50 ng IL-4 per ml, or a combination of cytokines. Data are expressed as mean picograms per 106 cells ±SD of triplicate cultures. In panels c and f are reported the ratios of IL-1ra to IL-1α in the supernatants and lysates, respectively, expressed as mean ±SD of three different experiments. (a) *p <0.002 vs untreated keratinocytes or keratinocytes stimulated with IFN-γ, IL-17, IL-4, or IFN-γ plus IL-17; (b) *p <0.004 vs untreated keratinocytes or keratinocytes treated with IL-4; (d), (e) *p <0.002 vs untreated keratinocytes; **p <0.002 vs keratinocytes stimulated with IFN-γ or IL-17; (c), (f) *p <0.004 vs untreated keratinocytes; **p <0.004 vs keratinocytes stimulated with IL-17 or IL-4. Journal of Investigative Dermatology 2000 115, 81-87DOI: (10.1046/j.1523-1747.2000.00041.x) Copyright © 2000 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 3 IL-17 and IL-4 upregulate IFN-γ-induced membrane ICAM-1 on cultured keratinocytes. Keratinocyte cultures were treated as indicated, and after 48 h were analyzed for membrane ICAM-1 and CD40 expression by flow cytometry. We used 100 U IFN-γ per ml, 50 ng IL-17, and IL-4 per ml. Dotted lines represent staining with matched isotype Ig. The x-axis and y-axis indicate the relative cell number and fluorescence intensity, respectively. Numbers indicate the mean fluorescence intensity subtracted from the fluorescence of control antibody. The net mean fluorescence intensities obtained from two other independent experiments were as follows: 10–6 (untreated cells), 1167–887 (IFN-γ), 1692–1351 (IFN-γ and IL-17), 1602–1350 (IFN-γ and IL-4), and 1995–1613 (IFN-γ, IL-17, and IL-4). Journal of Investigative Dermatology 2000 115, 81-87DOI: (10.1046/j.1523-1747.2000.00041.x) Copyright © 2000 The Society for Investigative Dermatology, Inc Terms and Conditions

Figure 4 IFN-γ selectively reduces IL-4R expression on keratinocytes. (a) Thirty micrograms of total proteins extracted from cultured keratinocytes after 48 h treatment with medium alone or the indicated cytokines (100 U IFN-γ per ml and 50 ng IL-17 or IL-4 per ml) were subjected to immunoblot analysis. IL-17 and IL-4 receptor staining were performed sequentially on the same filter with the m202 MoAb and the affinity-purified goat IgG anti-IL-4Rα chain, respectively. IFN-γR detection was carried out with a rabbit polyclonal antibody raised against the carboxy-terminus of the α subunit. One representative experiment of the three performed is shown. (b) Densitometric analysis of IL-17 (white bars), IL-4 (black bars), and IFN-γ (hatched bars) receptors. The densitometric units were obtained by dividing the values of receptor bands by the values of total proteins revealed by Coomassie blue staining of filters, and are expressed as mean ±SD of three independent experiments. *p <0.003 compared to unstimulated or IL-17- and/or IL-4-treated keratinocytes. Journal of Investigative Dermatology 2000 115, 81-87DOI: (10.1046/j.1523-1747.2000.00041.x) Copyright © 2000 The Society for Investigative Dermatology, Inc Terms and Conditions