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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD / genetics
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Antigens, CD / immunology
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Antigens, Differentiation, T-Lymphocyte / genetics
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Antigens, Differentiation, T-Lymphocyte / immunology
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CD4-Positive T-Lymphocytes / drug effects*
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CD4-Positive T-Lymphocytes / immunology
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CD4-Positive T-Lymphocytes / pathology
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Cell Differentiation / drug effects
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Chemokine CCL3 / genetics
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Chemokine CCL3 / immunology
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Chemokine CXCL10 / genetics
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Chemokine CXCL10 / immunology
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Chemokine CXCL9 / genetics
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Chemokine CXCL9 / immunology
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Dendritic Cells / drug effects
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Dendritic Cells / immunology
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Dendritic Cells / pathology
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Female
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Gene Expression Regulation
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Interferon-gamma / genetics
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Interferon-gamma / immunology*
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Interleukin-2 / genetics
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Interleukin-2 / immunology
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Interleukin-6 / genetics
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Interleukin-6 / immunology
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Lectins, C-Type / genetics
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Lectins, C-Type / immunology
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Mice
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Mice, Inbred C57BL
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Polysaccharides, Bacterial / biosynthesis
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Polysaccharides, Bacterial / pharmacology*
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Signal Transduction
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Spleen / drug effects
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Spleen / immunology
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Spleen / pathology
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Streptococcal Infections / genetics
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Streptococcal Infections / immunology*
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Streptococcal Infections / microbiology
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Streptococcal Infections / mortality
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Streptococcus agalactiae / immunology*
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Streptococcus agalactiae / metabolism
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Streptococcus agalactiae / pathogenicity
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Survival Analysis
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Tumor Necrosis Factor-alpha / genetics
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Tumor Necrosis Factor-alpha / immunology
Substances
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Antigens, CD
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Antigens, Differentiation, T-Lymphocyte
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CD69 antigen
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Ccl3 protein, mouse
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Chemokine CCL3
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Chemokine CXCL10
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Chemokine CXCL9
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Cxcl10 protein, mouse
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Cxcl9 protein, mouse
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Interleukin-2
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Interleukin-6
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Lectins, C-Type
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Polysaccharides, Bacterial
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Tumor Necrosis Factor-alpha
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interleukin-6, mouse
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Interferon-gamma