title: IL-4 modulation of CD4+CD25+ T regulatory cell-mediated suppression.
abstract: Murine CD4(+)CD25(+) T regulatory (Treg) cells were cocultured with CD4(+)CD25(-) Th cells and APCs or purified B cells and stimulated by anti-CD3 mAb. Replacement of APCs by B cells did not significantly affect the suppression of CD4(+)CD25(-) Th cells. When IL-4 was added to separate cell populations, this cytokine promoted CD4(+)CD25(-) Th and CD4(+)CD25(+) Treg cell proliferation, whereas the suppressive competence of CD4(+)CD25(+) Treg cells was preserved. Conversely, IL-4 added to coculture of APCs, CD4(+)CD25(-) Th cells, and CD4(+)CD25(+) Treg cells inhibited the suppression of CD4(+)CD25(-) Th cells by favoring their survival through the induction of Bcl-2 expression. At variance, suppression was not affected by addition of IL-13, although this cytokine shares with IL-4 a receptor chain. When naive CD4(+)CD25(-) Th cells were replaced by Th1 and Th2 cells, cell proliferation of both subsets was equally suppressed, but suppression was less pronounced compared with that of CD4(+)CD25(-) Th cells. IL-4 production by Th2 cells was also inhibited. These results indicate that although CD4(+)CD25(+) Treg cells inhibit IL-4 production, the addition of IL-4 counteracts CD4(+)CD25(+) Treg cell-mediated suppression by promoting CD4(+)CD25(-) Th cell survival and proliferation.
authors.affiliation: Laboratory of Immunology, Department of Biology, University of Rome Tor Vergata, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: Pace
authors.forename: Claudio
authors.initials: C
authors.lastname: Pioli
authors.forename: Gino
authors.initials: G
authors.lastname: Doria
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D006133:Growth Substances / Q000502:physiology; D018793:Interleukin-13 / Q000502:physiology; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis* / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism*; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D006133:Growth Substances; D018793:Interleukin-13; D019253:Proto-Oncogene Proteins c-bcl-2; D015375:Receptors, Interleukin-2; D015847:Interleukin-4