Anästhesiologie
Arbeitsgruppe Immunmodulatoren
| Group leader Dr. rer. nat. Ursula Wegenka E-mail: ursula.wegenka[at]uni-ulm.de Phone: +49 731 500 - 44536 |
|
Co-worker
Kristin Haugg (left), Technician E-mail: kristin.haugg[at]uniklinik-ulm.de
Heike Müller (right), PhD student E-mail: heike.mueller[at]uni-ulm.de |
|
contact | |
Dr. Ursula Wegenka Albert-Einstein-Allee 23 |
Albert-Einstein-Allee 23 |
Phone: +49 731 500 - 44536 |
Research topic:
Function of the new ‘IL-10 type’ cytokines IL-19, IL-20 and IL-24 in allergic and autoimmune diseases.
Modulation of local immune reactions by IL-10 type cytokines
The recently described cytokines IL-19, IL-20 and IL-24 share structural homology with IL-10 and are therefore classified as members of the IL-10 family of cytokines that also includes IL-22 and IL-26. Most members of the family bind to heterodimeric transmembrane receptor complexes that are composed of a long alpha-chain (R1) and a shorter ß-chain (R2). IL-19, IL-20 and IL-24 signal through IL-20R1/IL-20R2 heterodimeric receptor (IL-20R class I). In addition, IL-20 and IL-24 can also bind to IL-22R/IL-20R2 (IL-20R class II) heterodimer (Fig. 1).
Fig. 1: Schematic illustration of class II cytokines and their heterodimeric receptors. Ligands are shown above their receptor complexes. No mouse homologue of IL-26 has been reported so far. Light blue and light grey: extracellular fibronectin type III domains. Dark grey, blue and pink: intracellular domains. Functional receptor complexes consist of a R1 (or alpha) chain with a long intracellular part and a R2 (or ß) chain with a short intracellular domain (except for IL-22BP and TF). Special characteristics of this family are: some chains are recruited to more than one receptor complex (e.g. IL-20R2); one ligand can bind to several receptor complexes (e.g. IL-20), several cytokines can bind to one receptor heterodimer (e.g. IL-19, IL-20 and IL-24). Abbreviations: IFN, interferon; IFNGR, Interferony-receptor; IFNAR, Interferonalpha/ß-receptor; IL-22BP, IL-22-bindig protein; TF, Tissue-Factor. For review see Renauld JC., Nat Rev Immunol 2003;3(8):667-676.
Current knowledge of the biological effects of the ‘new’ IL-10 type cytokines is sparse. Despite their sequence homology to IL-10, none of these cytokines seems to have IL-10-like immune-suppressive functions. Cells of lymphoid or myeloid origin seem to be an important source for IL-19, IL-20 and IL-24. In addition, keratinocytes and other epithelial cells might also express the cytokines. There is strong evidence that IL-20 and IL-24 are implicated in psoriasis. Furthermore, their expression is enhanced in rheumatoid arthritis, atherosclerosis, asthma and inflammatory bowel diseases. Recombinant IL-20 and IL-24 promote angiogenesis. How IL-19, IL-20 and IL-24 influence the pathogenesis of immunological driven diseases is not conclusively resolved but quantitative analysis of the RNA expression of their receptor chains suggests, that epithelial cells are the major targets for these cytokines. Given their immune cell origins, these cytokines thus may be candidates for crosstalk between resident parenchymal cells of various organs with tissue-infiltrating leukocytes, monocytes and APC. It is still controversial if lymphocytes are targets for IL-19, IL-20 or IL-24.
To analyse the effects of IL-19, IL-20 and IL-24 on T-cells in vitro and on specific antigen dependent immune responses in vivo, we generated a knockout mouse with a genomic deletion of the first exon of IL-20R2 (Fig 2).
Fig. 2: Targeted disruption of the murine IL-20R2-gene. Genomic structure of murine IL-20R2 (A) (Chr. 9 E3.3; > 30kb; 7Exons), SS: signal peptide; FN: fibronectin-binding domain; EC: extracellular part; TM: transmembrane. IC: intracellular part; UTR: untranslated region. Knockout construct (B): target vector. TK-Neo: Neomycin resistance gene under control of thymidin-kinase promoter; HSV-TK: thymidine-kinase under control of Herpes simplex-promoter; P: PCR-Primer; S: Southern-probe. (C) Southern analysis of targeted ES cells and mice. (D) LPS induction of IL-20R2 RNA in wildtype but not in knockout mice (for details see Wahl et al. 2009).
The disruption of IL-20R2-gene disturbs signaling of IL-19, IL-20 and IL-24. Therefore we are able to analyse immune responses in vivo and in vitro, when signaling of all three cytokines is missing. For the first time we provide evidence that IL-20R2 modulates the T cell phenotype after activation in vivo and in vitro. We found that IL-20R2 enhances specific T cell responses to locally (i.m. or i.d.) applied DNA vaccines in vivo (Fig 3 A/B). Primary and secondary CD8 T cell responses to antigen were significantly higher in IL-20R2-/- mice than in IL-20R2+/- mice. In a T cell dependent model of contact hypersensitivity (CHS) knockout mice showed an increased response to the contact allergen TNCB (Fig 4). Thus, the cytokines IL-19, IL-20 and IL-24 act on CD8 and CD4 T cells and attenuate the development of specific CD8 T cell responses to DNA vaccines and contact allergens.
Fig. 3 Antigen specific CD8 and CD4 T cell responses to pCI/S and pCI/OVA vaccines in IL-20R2-/- and IL-20R2+/- mice. Mice were immunized with 50 µg (1 µg/ml) of pCI/S DNA vaccine (encoding HBSAg) into each tibialis muscle (100 µg plasmid/mouse). A second group of mice was immunized with 50 µg pCI/Ova DNA vaccine (encoding the complete OVA antigen) into each tibialis muscle. Twelve days post immunisation spleens were isolated and analysed for specific CD8 T cells reactive to HBsAg (A, left) or Ova by FACS (B). Freshly isolated cells were ex vivo restimulated for 4 h with Kb/S 190-197 in the presence of brefeldine A and stained with antibodies for intracellular IFNy and anti CD8 mAb (A, right). Mean values (± SD) of three mice per group are shown. The numbers of antigen primed, specific CD8 IFNy+ /105 CD8 T cells of three mice analysed by FACS analyses are shown (mean ± SD). (C) Freshly isolated cells were re-stimulated with S-particel. After 20 h brefeldine A was added. CD4 IFNy+ T cells were analysed by FACS.
Fig 4: IL-20R2 down regulates CHS reaction to TNCB BALB/c IL-20R2 deficient mice or wildtype littermates were painted on their abdominal skin with TNCB at day 0. Mice were re-challenged by painting with TNCB on both sides of the ears on day 5. Ear thickness from left and right ears was measured with an engineer’s micrometer (Mitutoyo) before and 24 h after challenge and ear swelling was calculated (Wahl et.al, 2009).
Selected publications
Renauld JC. Class II cytokine receptors and their ligands: key antiviral and inflammatory modulators. Nat Rev Immunol 2003;3(8):667-676.
Wahl C, Müller W, Leithäuser F, Adler G, Oswald F, Reimann J, et al. IL-20 receptor 2 signaling down-regulates antigen-specific T cell responses. J Immunol 2009;182(2):802-810.
Wegenka UM, Dikopoulos N, Reimann J, Adler G, Wahl C. The murine liver is a potential target organ for IL-19, IL-20 and IL-24: Type I Interferons and LPS regulate the expression of IL-20R2. J Hepatol 2007;46(2):257-265.
Schirmbeck R, Riedl P, Kupferschmitt M, Wegenka U, Hauser H, Rice J, et al. Priming protective CD8 T cell immunity by DNA vaccines encoding chimeric, stress protein-capturing tumor-associated antigen. J Immunol 2006;177(3):1534-1542.
Dikopoulos N, Wegenka U, Kröger A, Hauser HJ, Schirmbeck R, Reimann J. Recently primed CD8+ T cells entering the liver induce hepatocytes to interact with naive CD8+ T cells. Hepatology 2003; 39:1256-1266.
Wegenka UM, Buschmann J, Lütticken C, Heinrich PC, Horn F. Acute-phase response factor, a nuclear factor binding to acute-phase response elements, is rapidly activated by interleukin-6 at the posttranslational level. Mol Cell Biol 1993;13:276-288.
Lütticken C, Wegenka UM, Yuan J, Buschmann J, Schindler C, Ziemiecki A, Harpur AG, Wilks AF, Yasukawa K, Taga T. Association of transcription factor APRF and protein kinase Jak1 with the interleukin-6 signal transducer gp130. Science 1994;263:89-92.
Wegenka UM, Lütticken C, Buschmann J, Yuan J, Lottspeich F, Müller-Esterl W, Schindler C, Roeb E, Heinrich PC, Horn F. The interleukin-6-activated acute-phase response factor is antigenically and functionally related to members of the signal transducer and activator of transcription (STAT) family. Mol Cell Biol 1994;14:3186-3196.
Kooperation
AG F. Oswald, AG R. Schirmbeck, AG. J. Reimann, Department of Internal Medicine I, University Medical Center Ulm; F. Leithäuser, Department of Pathology, University Medical Center Ulm; AG K. Scharffetter-Kochanek, Department of Dermatology and Allergic Diseases, University Medical Center Ulm.
AG W. Müller, AG K. Else, Bill Ford Chair in Cellular Immunology, University of Manchester, Faculty of Life Sciences, Manchester, UK,
Drittmittelförderung
Deutsche Forschungsgemeinschaft ‘Funktion des IL-20R2 in antigenspezifischen T-Zell Antworten und der Delayed-type Hypersensitivitätsreaktion der Haut’ (DFG WE 3550/4-1)
nach oben