title: In vitro effects of dexamethasone on bovine CD25+CD4+ and CD25-CD4+ cells.
abstract: This paper investigates the in vitro effect of dexamethasone on bovine CD25highCD4+, CD25lowCD4+ and CD25-CD4+ T cells. Only a small percentage of bovine CD25highCD4+ (2-4%) and CD25lowCD4+ (1-2%) cells expressed Foxp3. Dexamethasone caused considerable loss of CD25-CD4+ cells, but it increased the relative and absolute numbers of CD25highCD4+ and CD25lowCD4+ lymphocytes, while at the same time reducing the percentage of Foxp3+ cells within the latter subpopulations. Considering all these, as well as the intrinsically poor Foxp3 expression in bovine CD25+CD4+, it can be concluded that the drug most probably increased the number of activated non-regulatory CD4+ lymphocytes. It has been found that changes in cell number were at least partly caused by proapoptotic effect of the drug on CD25-CD4+ cells and antiapoptotic effect on CD25highCD4+ and CD25lowCD4+ cells. The results obtained from this study indicate that the involvement of CD4+ lymphocytes in producing the anti-inflammatory and immunosuppressive effect of dexamethasone in cattle results from the fact that the drug had a depressive effect on the production of IFN-γ by CD25-CD4+ cells. Secretion of TGF-β and IL-10 by CD4+ lymphocytes was not involved in producing these pharmacological effects, because the drug did not affect production of TGF-β and, paradoxically, it reduced the percentage of IL-10+CD4+ cells.
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowski Street 13, 10-718 Olsztyn, Poland. tomasz.maslanka@uwm.edu.pl
authors.forename: Tomasz
authors.initials: T
authors.lastname: Maślanka
authors.forename: Jerzy Jan
authors.initials: JJ
authors.lastname: Jaroszewski
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D053645:Interleukin-2 Receptor alpha Subunit / Q000235:genetics / Q000378:metabolism*
chemical_list: D005938:Glucocorticoids; D053645:Interleukin-2 Receptor alpha Subunit; D003907:Dexamethasone