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  1. Article ; Online: Prolonged production of reactive oxygen species in response to B cell receptor stimulation promotes B cell activation and proliferation.

    Wheeler, Matthew L / Defranco, Anthony L

    Journal of immunology (Baltimore, Md. : 1950)

    2012  Volume 189, Issue 9, Page(s) 4405–4416

    Abstract: We have investigated the intracellular sources and physiological function of reactive oxygen species (ROS) produced in primary B cells in response to BCR stimulation. BCR stimulation of primary resting murine B cells induced the rapid production of ROS ... ...

    Abstract We have investigated the intracellular sources and physiological function of reactive oxygen species (ROS) produced in primary B cells in response to BCR stimulation. BCR stimulation of primary resting murine B cells induced the rapid production of ROS that occurred within minutes and was maintained for at least 24 h after receptor stimulation. While the early production of ROS (0-2 h) was dependent on the Nox2 isoform of NADPH oxidase, at later stages of B cell activation (6-24 h) ROS were generated by a second pathway, which appeared to be dependent on mitochondrial respiration. B cells from mice deficient in the Nox2 NADPH oxidase complex lacked detectable early production of extracellular and intracellular ROS after BCR stimulation but had normal proximal BCR signaling and BCR-induced activation and proliferation in vitro and mounted normal or somewhat elevated Ab responses in vivo. In contrast, neutralizing both pathways of BCR-derived ROS with the scavenger N-acetylcysteine resulted in impaired in vitro BCR-induced activation and proliferation and attenuated BCR signaling through the PI3K pathway at later times. These results indicate that the production of ROS downstream of the BCR is derived from at least two distinct cellular sources and plays a critical role at the later stages of B cell activation by promoting sustained BCR signaling via the PI3K pathway, which is needed for effective B cell responses to Ag.
    MeSH term(s) Animals ; B-Lymphocyte Subsets/cytology ; B-Lymphocyte Subsets/immunology ; B-Lymphocyte Subsets/metabolism ; Cell Proliferation ; Lymphocyte Activation/immunology ; Mice ; Mice, Inbred C57BL ; Mice, Mutant Strains ; Mice, Transgenic ; Reactive Oxygen Species/metabolism ; Receptors, Antigen, B-Cell/metabolism ; Receptors, Antigen, B-Cell/physiology ; Signal Transduction/immunology ; Time Factors
    Chemical Substances Reactive Oxygen Species ; Receptors, Antigen, B-Cell
    Language English
    Publishing date 2012-09-28
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 3056-9
    ISSN 1550-6606 ; 0022-1767 ; 1048-3233 ; 1047-7381
    ISSN (online) 1550-6606
    ISSN 0022-1767 ; 1048-3233 ; 1047-7381
    DOI 10.4049/jimmunol.1201433
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: TLR3 and TLR7 are targeted to the same intracellular compartments by distinct regulatory elements.

    Nishiya, Tadashi / Kajita, Emi / Miwa, Soichi / Defranco, Anthony L

    The Journal of biological chemistry

    2005  Volume 280, Issue 44, Page(s) 37107–37117

    Abstract: Toll-like receptor (TLR) 3 and TLR7 are indispensable for host defense against viral infection by recognizing virus-derived RNAs and are localized to intracellular membranes via an unknown mechanism. We recently reported experiments with chimeric Toll- ... ...

    Abstract Toll-like receptor (TLR) 3 and TLR7 are indispensable for host defense against viral infection by recognizing virus-derived RNAs and are localized to intracellular membranes via an unknown mechanism. We recently reported experiments with chimeric Toll-like receptors that suggested that the subcellular distribution of TLRs may be defined by their transmembrane and/or cytoplasmic domains. Here we demonstrate that the intracellular localization of TLR3 is achieved by a 23-amino acid sequence (Glu(727) to Asp(749)) present in the linker region between the transmembrane domain and Toll-interleukin 1 receptor resistance (TIR) domain. In contrast, the intracellular localization of TLR7 is achieved by its transmembrane domain. These elements also targeted a heterologous type I transmembrane protein CD25 to the intracellular compartment that contained TLR3 and TLR7. Despite their using distinct regulatory elements for intracellular localization, TLR3 was found to co-localize with TLR7. In addition, TLR3 and TLR7 were preferentially localized near phagosomes containing apoptotic cell particles. These findings reveal that TLR3 and TLR7 contain unique targeting sequences, which differentially lead them to the same intracellular compartments and adjacent to phagosomes containing apoptotic cell particles, where these receptors may access their ligands for the induction of immune responses against viral infection.
    MeSH term(s) 3T3 Cells ; Amino Acid Sequence ; Animals ; Apoptosis ; Cells, Cultured ; Cytoplasm/metabolism ; Fibroblasts ; Flow Cytometry ; Gene Expression Regulation ; Humans ; Kidney/metabolism ; Macrophages/cytology ; Macrophages/metabolism ; Mice ; Mice, Inbred C57BL ; Molecular Sequence Data ; Mutagenesis ; Mutation ; Phagosomes/metabolism ; Protein Structure, Tertiary ; Receptors, Interleukin-2/metabolism ; Recombinant Fusion Proteins/genetics ; Recombinant Fusion Proteins/metabolism ; Retroviridae/genetics ; Sequence Homology, Amino Acid ; Subcellular Fractions ; Toll-Like Receptor 3/genetics ; Toll-Like Receptor 3/metabolism ; Toll-Like Receptor 4/genetics ; Toll-Like Receptor 4/metabolism ; Toll-Like Receptor 7/genetics ; Toll-Like Receptor 7/metabolism
    Chemical Substances Receptors, Interleukin-2 ; Recombinant Fusion Proteins ; Toll-Like Receptor 3 ; Toll-Like Receptor 4 ; Toll-Like Receptor 7
    Language English
    Publishing date 2005-08-16
    Publishing country United States
    Document type Comparative Study ; Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    DOI 10.1074/jbc.M504951200
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Antiviral memory CD8 T-cell differentiation, maintenance, and secondary expansion occur independently of MyD88.

    Rahman, Adeeb H / Zhang, Ruan / Blosser, Christopher D / Hou, Baidong / Defranco, Anthony L / Maltzman, Jonathan S / Wherry, E John / Turka, Laurence A

    Blood

    2011  Volume 117, Issue 11, Page(s) 3123–3130

    Abstract: Inflammatory signals induced during infection regulate T-cell expansion, differentiation, and memory formation. Toll-like receptors (TLRs) are inflammatory mediators that allow innate immune cells to recognize and respond to invading pathogens. In ... ...

    Abstract Inflammatory signals induced during infection regulate T-cell expansion, differentiation, and memory formation. Toll-like receptors (TLRs) are inflammatory mediators that allow innate immune cells to recognize and respond to invading pathogens. In addition to their role in innate immune cells, we have found that signals delivered through the TLR adapter protein myeloid differentiation protein 88 (MyD88) play a critical, T cell-intrinsic role in supporting the survival and accumulation of antigen-specific effector cells after acute viral infection. However, the importance of MyD88-dependent signals in regulating the generation and maintenance of memory T cells remained unclear. To address this, we used a novel, inducible knockout system to examine whether MyD88 is required for optimal memory CD8 T-cell generation and responses after lymphocytic choriomeningitis virus infection. We show that whereas MyD88 is critical for initial T-cell expansion, it is not required for the subsequent differentiation and stable maintenance of a memory T-cell population. Furthermore, in contrast to naive CD8 T cells, memory CD8 T cells do not depend on MyD88 for their secondary expansion. Our findings clarify the importance of MyD88 during distinct phases of the antiviral T-cell response and establish differential dependence on MyD88 signaling as a novel characteristic that distinguishes naive from memory CD8 T cells.
    MeSH term(s) Animals ; CD8-Positive T-Lymphocytes/cytology ; CD8-Positive T-Lymphocytes/drug effects ; CD8-Positive T-Lymphocytes/immunology ; Cell Differentiation/drug effects ; Cell Differentiation/immunology ; Cell Proliferation/drug effects ; Cytokines/biosynthesis ; Gene Deletion ; Immunologic Memory/drug effects ; Immunologic Memory/immunology ; Lymphocytic Choriomeningitis/immunology ; Lymphocytic Choriomeningitis/virology ; Lymphocytic choriomeningitis virus/drug effects ; Lymphocytic choriomeningitis virus/immunology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Myeloid Differentiation Factor 88/metabolism ; Tamoxifen/pharmacology
    Chemical Substances Cytokines ; Myeloid Differentiation Factor 88 ; Tamoxifen (094ZI81Y45)
    Language English
    Publishing date 2011-01-13
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 80069-7
    ISSN 1528-0020 ; 0006-4971
    ISSN (online) 1528-0020
    ISSN 0006-4971
    DOI 10.1182/blood-2010-11-318485
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Myeloid cells, BAFF, and IFN-gamma establish an inflammatory loop that exacerbates autoimmunity in Lyn-deficient mice.

    Scapini, Patrizia / Hu, Yongmei / Chu, Ching-Liang / Migone, Thi-Sau / Defranco, Anthony L / Cassatella, Marco A / Lowell, Clifford A

    The Journal of experimental medicine

    2010  Volume 207, Issue 8, Page(s) 1757–1773

    Abstract: Autoimmunity is traditionally attributed to altered lymphoid cell selection and/or tolerance, whereas the contribution of innate immune cells is less well understood. Autoimmunity is also associated with increased levels of B cell-activating factor of ... ...

    Abstract Autoimmunity is traditionally attributed to altered lymphoid cell selection and/or tolerance, whereas the contribution of innate immune cells is less well understood. Autoimmunity is also associated with increased levels of B cell-activating factor of the TNF family (BAFF; also known as B lymphocyte stimulator), a cytokine that promotes survival of self-reactive B cell clones. We describe an important role for myeloid cells in autoimmune disease progression. Using Lyn-deficient mice, we show that overproduction of BAFF by hyperactive myeloid cells contributes to inflammation and autoimmunity in part by acting directly on T cells to induce the release of IFN-gamma. Genetic deletion of IFN-gamma or reduction of BAFF activity, achieved by either reducing myeloid cell hyperproduction or by treating with an anti-BAFF monoclonal antibody, reduced disease development in lyn(-/-) mice. The increased production of IFN-gamma in lyn(-/-) mice feeds back on the myeloid cells to further stimulate BAFF release. Expression of BAFF receptor on T cells was required for their full activation and IFN-gamma release. Overall, our data suggest that the reciprocal production of BAFF and IFN-gamma establishes an inflammatory loop between myeloid cells and T cells that exacerbates autoimmunity in this model. Our findings uncover an important pathological role of BAFF in autoimmune disorders.
    MeSH term(s) Adoptive Transfer ; Animals ; Antibodies, Monoclonal/immunology ; Antibodies, Monoclonal/pharmacology ; Autoantibodies/blood ; Autoantibodies/immunology ; Autoimmunity/genetics ; Autoimmunity/immunology ; B-Cell Activating Factor/blood ; B-Cell Activating Factor/genetics ; B-Cell Activating Factor/immunology ; B-Cell Activating Factor/metabolism ; B-Cell Activation Factor Receptor/genetics ; B-Lymphocytes/cytology ; B-Lymphocytes/drug effects ; B-Lymphocytes/immunology ; B-Lymphocytes/metabolism ; Cell Proliferation/drug effects ; Dendritic Cells/cytology ; Dendritic Cells/immunology ; Dendritic Cells/metabolism ; Gene Expression/genetics ; Gene Expression/immunology ; Inflammation/immunology ; Interferon-gamma/blood ; Interferon-gamma/genetics ; Interferon-gamma/metabolism ; Interferon-gamma/pharmacology ; Lymphocyte Activation/drug effects ; Lymphocyte Activation/genetics ; Lymphocyte Activation/immunology ; Macrophages/cytology ; Macrophages/immunology ; Macrophages/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Models, Immunological ; Myeloid Cells/cytology ; Myeloid Cells/drug effects ; Myeloid Cells/immunology ; Myeloid Cells/metabolism ; Nephritis/genetics ; Nephritis/immunology ; Nephritis/metabolism ; Proto-Oncogene Proteins/genetics ; Proto-Oncogene Proteins c-hck/genetics ; Spleen/cytology ; Spleen/metabolism ; Spleen/pathology ; Splenomegaly/genetics ; Splenomegaly/immunology ; T-Lymphocytes/cytology ; T-Lymphocytes/drug effects ; T-Lymphocytes/immunology ; T-Lymphocytes/metabolism ; T-Lymphocytes/transplantation ; src-Family Kinases/genetics
    Chemical Substances Antibodies, Monoclonal ; Autoantibodies ; B-Cell Activating Factor ; B-Cell Activation Factor Receptor ; Proto-Oncogene Proteins ; Tnfrsf13c protein, mouse ; Tnfsf13b protein, mouse ; Interferon-gamma (82115-62-6) ; Hck protein, mouse (EC 2.7.10.2) ; Proto-Oncogene Proteins c-hck (EC 2.7.10.2) ; lyn protein-tyrosine kinase (EC 2.7.10.2) ; proto-oncogene proteins c-fgr (EC 2.7.10.2) ; src-Family Kinases (EC 2.7.10.2)
    Language English
    Publishing date 2010-07-12
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 218343-2
    ISSN 1540-9538 ; 0022-1007
    ISSN (online) 1540-9538
    ISSN 0022-1007
    DOI 10.1084/jem.20100086
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  5. Article ; Online: Parasite-induced TH1 cells and intestinal dysbiosis cooperate in IFN-γ-dependent elimination of Paneth cells.

    Raetz, Megan / Hwang, Sun-Hee / Wilhelm, Cara L / Kirkland, Donna / Benson, Alicia / Sturge, Carolyn R / Mirpuri, Julie / Vaishnava, Shipra / Hou, Baidong / Defranco, Anthony L / Gilpin, Christopher J / Hooper, Lora V / Yarovinsky, Felix

    Nature immunology

    2012  Volume 14, Issue 2, Page(s) 136–142

    Abstract: Activation of Toll-like receptors (TLRs) by pathogens triggers cytokine production and T cell activation, immune defense mechanisms that are linked to immunopathology. Here we show that IFN-γ production by CD4(+) T(H)1 cells during mucosal responses to ... ...

    Abstract Activation of Toll-like receptors (TLRs) by pathogens triggers cytokine production and T cell activation, immune defense mechanisms that are linked to immunopathology. Here we show that IFN-γ production by CD4(+) T(H)1 cells during mucosal responses to the protozoan parasite Toxoplasma gondii resulted in dysbiosis and the elimination of Paneth cells. Paneth cell death led to loss of antimicrobial peptides and occurred in conjunction with uncontrolled expansion of the Enterobacteriaceae family of Gram-negative bacteria. The expanded intestinal bacteria were required for the parasite-induced intestinal pathology. The investigation of cell type-specific factors regulating T(H)1 polarization during T. gondii infection identified the T cell-intrinsic TLR pathway as a major regulator of IFN-γ production in CD4(+) T cells responsible for Paneth cell death, dysbiosis and intestinal immunopathology.
    MeSH term(s) Animals ; CD4-Positive T-Lymphocytes ; Cell Death ; Enterobacteriaceae/growth & development ; Enterobacteriaceae/immunology ; Enterobacteriaceae Infections/complications ; Enterobacteriaceae Infections/immunology ; Enterobacteriaceae Infections/microbiology ; Enterobacteriaceae Infections/pathology ; Gene Expression Regulation ; Host-Parasite Interactions ; Host-Pathogen Interactions ; Interferon-gamma/genetics ; Interferon-gamma/immunology ; Interleukin-12/genetics ; Interleukin-12/immunology ; Lymphocyte Activation ; Mice ; Mice, Transgenic ; Paneth Cells/microbiology ; Paneth Cells/parasitology ; Paneth Cells/pathology ; Receptors, Antigen, T-Cell/genetics ; Receptors, Antigen, T-Cell/immunology ; Signal Transduction/immunology ; Th1 Cells/microbiology ; Th1 Cells/parasitology ; Th1 Cells/pathology ; Toxoplasma/growth & development ; Toxoplasma/immunology ; Toxoplasmosis, Animal/complications ; Toxoplasmosis, Animal/immunology ; Toxoplasmosis, Animal/parasitology ; Toxoplasmosis, Animal/pathology ; alpha-Defensins/deficiency
    Chemical Substances Receptors, Antigen, T-Cell ; alpha-Defensins ; Interleukin-12 (187348-17-0) ; Interferon-gamma (82115-62-6)
    Language English
    Publishing date 2012-12-23
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2016987-5
    ISSN 1529-2916 ; 1529-2908
    ISSN (online) 1529-2916
    ISSN 1529-2908
    DOI 10.1038/ni.2508
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Dendritic cell expression of the signaling molecule TRAF6 is critical for gut microbiota-dependent immune tolerance.

    Han, Daehee / Walsh, Matthew C / Cejas, Pedro J / Dang, Nicholas N / Kim, Youngmi F / Kim, Jihyun / Charrier-Hisamuddin, Laetitia / Chau, Lillian / Zhang, Qin / Bittinger, Kyle / Bushman, Frederic D / Turka, Laurence A / Shen, Hao / Reizis, Boris / Defranco, Anthony L / Wu, Gary D / Choi, Yongwon

    Immunity

    2013  Volume 38, Issue 6, Page(s) 1211–1222

    Abstract: The intracellular signaling molecule TRAF6 is critical for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). We now report that DC-specific deletion of TRAF6 (TRAF6ΔDC) resulted, unexpectedly, in loss of mucosal tolerance, ... ...

    Abstract The intracellular signaling molecule TRAF6 is critical for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). We now report that DC-specific deletion of TRAF6 (TRAF6ΔDC) resulted, unexpectedly, in loss of mucosal tolerance, characterized by spontaneous development of T helper 2 (Th2) cells in the lamina propria and eosinophilic enteritis and fibrosis in the small intestine. Loss of tolerance required the presence of gut commensal microbiota but was independent of DC-expressed MyD88. Further, TRAF6ΔDC mice exhibited decreased regulatory T (Treg) cell numbers in the small intestine and diminished induction of iTreg cells in response to model antigen. Evidence suggested that this defect was associated with diminished DC expression of interleukin-2 (IL-2). Finally, we demonstrate that aberrant Th2 cell-associated responses in TRAF6ΔDC mice could be mitigated via restoration of Treg cell activity. Collectively, our findings reveal a role for TRAF6 in directing DC maintenance of intestinal immune tolerance through balanced induction of Treg versus Th2 cell immunity.
    MeSH term(s) Animals ; Cells, Cultured ; Dendritic Cells/immunology ; Dendritic Cells/microbiology ; Enteritis/genetics ; Enteritis/immunology ; Eosinophilia/genetics ; Eosinophilia/immunology ; Eosinophils/immunology ; Gastritis/genetics ; Gastritis/immunology ; Gene Expression Regulation/genetics ; Gene Expression Regulation/immunology ; Immune Tolerance/genetics ; Interleukin-2/genetics ; Interleukin-2/metabolism ; Intestines/immunology ; Intestines/microbiology ; Intestines/pathology ; Lymphocyte Activation/genetics ; Metagenome/immunology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Myeloid Differentiation Factor 88/genetics ; Myeloid Differentiation Factor 88/metabolism ; Signal Transduction/genetics ; T-Lymphocytes, Regulatory/immunology ; T-Lymphocytes, Regulatory/microbiology ; TNF Receptor-Associated Factor 6/genetics ; TNF Receptor-Associated Factor 6/immunology ; TNF Receptor-Associated Factor 6/metabolism ; Th2 Cells/immunology ; Th2 Cells/microbiology
    Chemical Substances Interleukin-2 ; Myeloid Differentiation Factor 88 ; TNF Receptor-Associated Factor 6
    Language English
    Publishing date 2013-06-20
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 1217235-2
    ISSN 1097-4180 ; 1074-7613
    ISSN (online) 1097-4180
    ISSN 1074-7613
    DOI 10.1016/j.immuni.2013.05.012
    Database MEDical Literature Analysis and Retrieval System OnLINE

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