title: Interleukin-4 downregulates CD127 expression and activity on human thymocytes and mature CD8+ T cells.
abstract: Signaling via the IL-7 receptor complex (IL-7Ralpha/CD127 and IL-2Rgamma/CD132) is required for T-cell development and survival. Decreased CD127 expression has been associated with persistent viral infections (e.g. HIV, HCV) and cancer. Many IL-2Rgamma-sharing (gammaC) cytokines decrease CD127 expression on CD4+ and CD8+ T cells in mice (IL-2, IL-4, IL-7, IL-15) and in humans (IL-2, IL-7), suggesting a common function. IL-4 is of particular interest as it is upregulated in HIV infection and in thyroid and colon cancers. The role of IL-4 in regulating CD127 expression and IL-7 activity in human thymocytes and mature CD8+ T cells is unknown and was therefore investigated. IL-4 decreased CD127 expression on all thymocyte subsets tested and only on naïve (CD45RA+) CD8+ T cells, without altering membrane-bound CD127 mRNA expression. Pre-treatment of thymocytes or CD8+ T cells with IL-4 inhibited IL-7-mediated phosphorylation of STAT5 and decreased proliferation of CD8+ T cells. By downregulating CD127 expression and signaling on developing thymocytes and CD8+ T cells, IL-4 is a potential contributor to impaired CD8+ T-cell function in some anti-viral and anti-tumor responses. These findings are of particular consequence to diseases such as HIV, HCV, RSV, measles and cancer, in which CD127 expression is decreased, IL-7 activity is impaired and IL-4 concentrations are elevated.
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Crawley
authors.forename: Agatha
authors.initials: A
authors.lastname: Vranjkovic
authors.forename: Charlene
authors.initials: C
authors.lastname: Young
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Angel
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D018920:Coculture Techniques; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology*; D015851:Interleukin-7 / Q000378:metabolism; D053699:Interleukin-7 Receptor alpha Subunit / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D050799:STAT5 Transcription Factor / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology*
chemical_list: C508605:IL7 protein, human; D015851:Interleukin-7; D053699:Interleukin-7 Receptor alpha Subunit; D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; D015847:Interleukin-4