title: Type 2 cytotoxic T lymphocytes modulate the activity of dendritic cells toward type 2 immune responses.
abstract: Activated CD8+ T cells can differentiate into type 1 (Tc1) cells, producing mainly IFN-gamma, and type 2 (Tc2) cells, producing mostly IL-4, IL-5, and IL-10. Tc1 cells are potent CTL involved in the defense against intracellular pathogens and cancer cells. The role of Tc2 cells in the immune response is largely unknown, although their presence in chronic infections, cancer, and autoimmune diseases is associated with disease severity and progression. Here, we show that mouse Tc2 cells modify, through a cell-to-cell contact mechanism, the function of bone marrow-derived dendritic cells (DC). Indeed, Tc2-conditioned DC displayed a reduced expression of MHC class II and costimulatory molecules, produced IL-10 instead of IL-12, and favored the differentiation of both naive CD4+ and CD8+ T cells toward type 2 cells in the absence of added polarizing cytokines. The novel function for Tc2 cells suggests a type 2 loop in which Tc2 cells modify DC function and favor differentiation of naive T cells to type 2 cells. The type 2 loop may at least in part explain the unexpected high frequency of type 2 cells during a chronic exposure to the Ag.
authors.affiliation: Cancer Immunotherapy and Gene Therapy Program, Istituto Scientifico H San Raffaele, Via Olgettina 58, 20132 Milan, Italy.
authors.forename: Giandomenica
authors.initials: G
authors.lastname: Iezzi
authors.forename: Andrea
authors.initials: A
authors.lastname: Boni
authors.forename: Elena
authors.initials: E
authors.lastname: Degl'Innocenti
authors.forename: Matteo
authors.initials: M
authors.lastname: Grioni
authors.forename: Maria T S
authors.initials: MT
authors.lastname: Bertilaccio
authors.forename: Matteo
authors.initials: M
authors.lastname: Bellone
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000502:physiology; D005260:Female; D016130:Immunophenotyping; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016176:T-Lymphocyte Subsets / Q000145:classification / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
chemical_list: D018984:Epitopes, T-Lymphocyte