title: Group B Streptococcus Induces a Robust IFN-γ Response by CD4(+) T Cells in an In Vitro and In Vivo Model.
abstract: Group B Streptococcus (GBS) serotype III causes life-threatening infections. Cytokines have emerged as important players for the control of disease, particularly IFN-γ. Although potential sources of this cytokine have been proposed, no specific cell line has ever been described as a leading contributor. In this study, CD4(+) T cell activation profiles in response to GBS were evaluated through in vivo, ex vivo, and in vitro approaches. Total splenocytes readily produce a type 1 proinflammatory response by releasing IFN-γ, TNF-α, and IL-6 and actively recruit T cells via chemokines like CXCL9, CXCL10, and CCL3. Responding CD4(+) T cells differentiate into Th1 cells producing large amounts of IFN-γ, TNF-α, and IL-2. In vitro studies using dendritic cell and CD4(+) T cell cocultures infected with wild-type GBS or a nonencapsulated mutant suggested that GBS capsular polysaccharide, one of the major bacterial virulence factors, differentially modulates surface expression of CD69 and IFN-γ production. Overall, CD4(+) T cells are important producers of IFN-γ and might thus influence the course of GBS infection through the expression balance of this cytokine.
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada J2S 2M2.
authors.forename: Damian
authors.initials: D
authors.lastname: Clarke
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada J2S 2M2.
authors.forename: Corinne
authors.initials: C
authors.lastname: Letendre
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada J2S 2M2.
authors.forename: Marie-Pier
authors.initials: MP
authors.lastname: Lecours
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada J2S 2M2.
authors.forename: Paul
authors.initials: P
authors.lastname: Lemire
authors.affiliation: Laboratory of Molecular Immunology, Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, QC, Canada H3C 3J7.
authors.forename: Tristan
authors.initials: T
authors.lastname: Galbas
authors.affiliation: Laboratory of Molecular Immunology, Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, QC, Canada H3C 3J7.
authors.forename: Jacques
authors.initials: J
authors.lastname: Thibodeau
authors.affiliation: Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada J2S 2M2.
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D054405:Chemokine CCL3 / Q000235:genetics / Q000276:immunology; D054357:Chemokine CXCL10 / Q000235:genetics / Q000276:immunology; D054370:Chemokine CXCL9 / Q000235:genetics / Q000276:immunology; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology*; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology; D015850:Interleukin-6 / Q000235:genetics / Q000276:immunology; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000494:pharmacology*; D015398:Signal Transduction; D013154:Spleen / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D013290:Streptococcal Infections / Q000235:genetics / Q000276:immunology* / Q000382:microbiology / Q000401:mortality; D013292:Streptococcus agalactiae / Q000276:immunology* / Q000378:metabolism / Q000472:pathogenicity; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D054405:Chemokine CCL3; D054357:Chemokine CXCL10; D054370:Chemokine CXCL9; D007371:Interferon-gamma; D007376:Interleukin-2; D015850:Interleukin-6; D037181:Lectins, C-Type; D011135:Polysaccharides, Bacterial; D014409:Tumor Necrosis Factor-alpha; D000099192:CD69 Antigens; C496534:Ccl3 protein, mouse; C485433:Cxcl10 protein, mouse; C485969:Cxcl9 protein, mouse; C577686:interleukin-6, mouse