title: Natural and inducible Tregs in swine: Helios expression and functional properties.
abstract: Within the population of regulatory T cells (Tregs) natural Tregs (nTregs) and inducible Tregs (iTregs) can be distinguished. Although information about Tregs in swine exists, porcine iTregs were not under investigation yet. In this study, Foxp3(+) iTregs were generated from CD4(+)Foxp3(-) T cells by in vitro stimulation in the presence of IL-2 and TGF-β. In comparison to ex vivo Tregs these iTregs had a similar suppressive capacity on the proliferation of CD3-stimulated PBMC, caused higher levels of IL-10 in PBMC/Treg co-cultures, but did not suppress IFN-γ levels. The Ikaros family member Helios is currently discussed to distinguish iTregs and nTregs or to serve as an activation marker of Tregs. In this study, we demonstrate the cross-reactivity of an anti-mouse/human Helios mAb with porcine Helios. Flow cytometric analyses with this antibody showed that porcine iTregs do not express Helios after in vitro iTreg induction. Nevertheless, thymic Foxp3(+) T cells, which arise at the CD4/CD8α single-positive stage of T-cell development and are defined as nTregs, entirely expressed Helios. Although this might suggest the suitability of Helios as an nTreg-iTreg differentiation marker we also found that Helios(-) Tregs displayed a phenotype of naive CD4(+) T cells in vivo. Since iTregs are by definition activated/differentiated Tregs, this finding precludes that all Helios(-) Tregs are iTregs and thus also the use of Helios as a selection marker for porcine nTregs. Furthermore, Helios(+) Tregs displayed a more differentiated phenotype indicating that Helios might rather serve as a Treg activation/differentiation marker.
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria. Electronic address: tobias.kaeser@usask.ca.
authors.forename: Tobias
authors.initials: T
authors.lastname: Käser
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
authors.forename: Kerstin H
authors.initials: KH
authors.lastname: Mair
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
authors.forename: Sabine E
authors.initials: SE
authors.lastname: Hammer
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Gerner
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
authors.forename: Armin
authors.initials: A
authors.lastname: Saalmüller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015415:Biomarkers; D017252:CD3 Complex / Q000096:biosynthesis; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D051858:Forkhead Transcription Factors / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051740:Ikaros Transcription Factor / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis*; D016753:Interleukin-10 / Q000378:metabolism; D007376:Interleukin-2 / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008969:Molecular Sequence Data; D013552:Swine; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000276:immunology / Q000378:metabolism
chemical_list: D015415:Biomarkers; D017252:CD3 Complex; D051858:Forkhead Transcription Factors; C111431:IKZF2 protein, human; C556062:IL10 protein, mouse; D007376:Interleukin-2; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D051740:Ikaros Transcription Factor; D007371:Interferon-gamma
keywords: CD4(+); Helios; Pig; Regulatory T cells; iTregs; nTregs