title: IL-2 regulates FOXP3 expression in human CD4+CD25+ regulatory T cells through a STAT-dependent mechanism and induces the expansion of these cells in vivo.
abstract: IL-2 plays a critical role in the maintenance of CD4+CD25+ FOXP3(+) regulatory T cells (Tregs) in vivo. We examined the effects of IL-2 signaling in human Tregs. In vitro, IL-2 selectively up-regulated the expression of FOXP3 in purified CD4+CD25+ T cells but not in CD4+CD25- cells. This regulation involved the binding of STAT3 and STAT5 proteins to a highly conserved STAT-binding site located in the first intron of the FOXP3 gene. We also examined the effects of low-dose IL-2 treatment in 12 patients with metastatic cancer and 9 patients with chronic myelogenous leukemia after allogeneic hematopoietic stem cell transplantation. Overall, IL-2 treatment resulted in a 1.9 median fold increase in the frequency of CD4+CD25+ cells in peripheral blood as well as a 9.7 median fold increase in FOXP3 expression in CD3+ T cells. CD56+CD3- natural killer (NK) cells also expanded during IL-2 therapy but did not express FOXP3. In vitro treatment of NK cells with 5-aza-2'-deoxycytidine restored the IL-2 signaling pathway leading to FOXP3 expression, suggesting that this gene was constitutively repressed by DNA methylation in these cells. Our findings support the clinical evaluation of low-dose IL-2 to selectively modulate CD4+CD25+ Tregs and increase expression of FOXP3 in vivo.
authors.affiliation: Division of Hematologic Malignancies, Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Zorn
authors.forename: Erik A
authors.initials: EA
authors.lastname: Nelson
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Mohseni
authors.forename: Fabrice
authors.initials: F
authors.lastname: Porcheray
authors.forename: Haesook
authors.initials: H
authors.lastname: Kim
authors.forename: Despina
authors.initials: D
authors.lastname: Litsa
authors.forename: Roberto
authors.initials: R
authors.lastname: Bellucci
authors.forename: Elke
authors.initials: E
authors.lastname: Raderschall
authors.forename: Christine
authors.initials: C
authors.lastname: Canning
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Soiffer
authors.forename: David A
authors.initials: DA
authors.lastname: Frank
authors.forename: Jerome
authors.initials: J
authors.lastname: Ritz
mesh_terms: D015703:Antigens, CD / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D002455:Cell Division; D051858:Forkhead Transcription Factors / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology / Q000627:therapeutic use*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000276:immunology*; D009369:Neoplasms / Q000188:drug therapy* / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000097:blood*; D050791:STAT Transcription Factors / Q000502:physiology*; D033581:Stem Cell Transplantation; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
chemical_list: D015703:Antigens, CD; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D050791:STAT Transcription Factors