title: Porcine regulatory T cells: mechanisms and T-cell targets of suppression.
abstract: Tregs are known for their suppressive capacity on various immune reactions. In swine, existence as well as suppressive activity of Foxp3(+) Tregs could be demonstrated but detailed functional investigations are lacking. Therefore, we analysed the functional properties of porcine Tregs. We observed that besides TCR stimulation Tregs require IL-2 for activation. Furthermore, we investigated the following mechanisms of suppression: (i) cell-cell contact dependency, (ii) production of soluble suppressive factors and (iii) competition for growth factors. Our experiments revealed that suppression by porcine Tregs is abrogated by blocking cell-cell contact or by supplementing excessive amounts of IL-2. Additionally it could be shown that porcine Tregs produce immunosuppressive IL-10. Thereby, we demonstrated that porcine Tregs can use all main mechanisms of suppression mentioned above. Further investigations on the suppressive activity of Tregs using CFSE proliferation assays demonstrated that suppression affects T-helper cells as well as cytotoxic T lymphocytes and TCR-γδ T cells.
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria. tobias.kaeser@vetmeduni.ac.at
authors.forename: Tobias
authors.initials: T
authors.lastname: Käser
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Gerner
authors.forename: Armin
authors.initials: A
authors.lastname: Saalmüller
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002450:Cell Communication; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000378:metabolism; D007108:Immune Tolerance; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology / Q000378:metabolism; D013552:Swine / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D051858:Forkhead Transcription Factors; D007376:Interleukin-2; D016692:Receptors, Antigen, T-Cell, gamma-delta; D016753:Interleukin-10