title: Development in vitro of human CD4+ thymocytes into functionally mature Th2 cells. Exogenous interleukin-12 is required for priming thymocytes to produce both Th1 cytokines and interleukin-10.
abstract: Fresh postnatal thymocyte cell suspensions were directly cloned under limiting dilution conditions with either phytohemagglutinin or toxic shock syndrome toxin-1 (TSST-1), a bacterial superantigen. Cultures contained allogenic irradiated feeder cells and interleukin (IL)-2, in the absence or presence of exogenous IL-4, interferon (IFN)-gamma or IL-12. The resulting CD4+ T cell clones generated under these different experimental conditions were then analyzed for their ability to produce IL-2, IL-4, IL-5, IL-10, IFN-gamma and tumor necrosis factor (TNF)-beta in response to stimulation with phorbol 12-myristate 13-acetate (PMA) + anti-CD3 monoclonal antibody or PMA + ionomycin. Different from T cell clones generated from peripheral blood, virtually all CD4+ T cell clones generated from human thymocytes produced high concentrations of IL-2, IL-4 and IL-5, but no IFN-gamma, TNF-beta or IL-10. Moreover, after activation, these clones expressed on their surface membrane both CD30 and CD40 ligand, but not the product of lymphocyte activation gene (LAG)-3, and provided strong helper activity for IgE synthesis by allogeneic B cells. The Th2 cytokine pattern could not be modified by the addition of IFN-gamma. However, upon addition of exogenous IL-12, the resulting CD4+ thymocyte clones produced TNF-beta, IFN-gamma, and IL-10 in addition to IL-4 and IL-5. These results suggest that CD4+ human thymocytes have the potential to develop into cells producing the Th2 cytokines IL-4 and IL-5, whereas the ability to produce both Th1 cytokines and IL-10 is acquired only after priming with IL-12.
authors.affiliation: Istituto di Oncologia Clinica e Sperimentale, University of Genoa, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Mingari
authors.forename: E
authors.initials: E
authors.lastname: Maggi
authors.forename: A
authors.initials: A
authors.lastname: Cambiaggi
authors.forename: F
authors.initials: F
authors.lastname: Annunziato
authors.forename: F
authors.initials: F
authors.lastname: Schiavetti
authors.forename: R
authors.initials: R
authors.lastname: Manetti
authors.forename: L
authors.initials: L
authors.lastname: Moretta
authors.forename: S
authors.initials: S
authors.lastname: Romagnani
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D002675:Child, Preschool; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis*; D018664:Interleukin-12 / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D018417:Th1 Cells / Q000187:drug effects / Q000378:metabolism*; D018418:Th2 Cells / Q000166:cytology* / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D016207:Cytokines; D016753:Interleukin-10; D018664:Interleukin-12