Specific Immunotherapy to Birch Allergen Does not Enhance Suppression of Th2 Cells by CD4+CD25+ Regulatory T Cells During Pollen Season
The aim of this study was to investigate the suppressive capacity of CD25+ regulatory T cells on birch allergen-induced T-cell responses during the first birch pollen season after initiation of specific immunotherapy (SIT).
CD25pos and CD25neg T cells were purified from blood of birch-allergic SIT patients and birch-allergic controls, stimulated with birch pollen extract, and analyzed for T-cell proliferation and production of interferon gamma (IFN-γ), interleukin (IL)-5 and IL-10.
We show that allergen-induced proliferation and IFN-γ production were suppressed equally well by CD25pos T cells from SIT patients and controls, while the IL-5 production was not suppressed by either of the groups. IL-10 levels were higher in SIT patients relative to controls only when CD25neg and CD25pos were cultured together. Furthermore, neither FOXP3 levels nor proportions of CD25high T cells were enhanced in SIT patients compared to allergic controls.
These results suggest that the Th2-suppressive capacity of allergen-stimulated CD25pos Treg in vitro is not improved by SIT in spite of increased IL-10 production from T cells.
KeywordsHuman CD4+CD25+ regulatory T cells allergy immunotherapy suppression IL-10
We are grateful to the study nurse Yvonne Bäckberg for skilfull assistance, and we thank all volunteers for donating blood to the study. This work was supported by the Medical Faculty, Göteborg University; the Swedish Research Council (grant K2002-745X-14455-01A); Vårdal Foundation; the Swedish Asthma and Allergy Association Research Foundation; and Göteborg Medical Society, Frimurare Barnhus-direktionen.
- 11.Buelens C, Verhasselt V, De Groote D, Thielemans K, Goldman M, Willems F. Interleukin-10 prevents the generation of dendritic cells from human peripheral blood mononuclear cells cultured with interleukin-4 and granulocyte/macrophage-colony-stimulating factor. Eur J Immunol. 1997;27:756–62.CrossRefPubMedGoogle Scholar
- 12.de Waal Malefyt R, Haanen J, Spits H, Roncarolo MG, te Velde A, Figdor C, et al. Interleukin 10 (IL-10) and viral IL-10 strongly reduce antigen-specific human T cell proliferation by diminishing the antigen-presenting capacity of monocytes via downregulation of class II major histocompatibility complex expression. J Exp Med. 1991;174:915–24.CrossRefPubMedGoogle Scholar
- 22.Gardner LM, Thien FC, Douglass JA, Rolland JM, O’Hehir RE. Induction of T ‘regulatory’ cells by standardized house dust mite immunotherapy: an increase in CD4+CD25+ interleukin-10+ T cells expressing peripheral tissue trafficking markers. Clin Exp Allergy. 2004;34:1209–19.CrossRefPubMedGoogle Scholar