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Your search keyword '"Stephen Laroux"' showing total 2 results
Start Over Author "Stephen Laroux" Journal the journal of immunology
2 results on '"Stephen Laroux"'

1. Cutting Edge: MyD88 Controls Phagocyte NADPH Oxidase Function and Killing of Gram-Negative Bacteria

Author

F. Stephen Laroux, Xavier Romero, Lee M. Wetzler, Cox Terhorst, and Pablo Engel

Subjects
Gram-negative bacteria, Phagocyte, Phagocytosis, Immunology, p38 Mitogen-Activated Protein Kinases, Microbiology, Mice, chemistry.chemical_compound, Gram-Negative Bacteria, medicine, Animals, Immunology and Allergy, Phosphorylation, Receptors, Immunologic, Adaptor Proteins, Signal Transducing, Oxidase test, NADPH oxidase, Innate immune system, biology, Superoxide, Macrophages, NADPH Oxidases, biology.organism_classification, Antigens, Differentiation, Mice, Inbred C57BL, medicine.anatomical_structure, chemistry, Myeloid Differentiation Factor 88, biology.protein, Bacteria
Abstract

MyD88 is an adaptor protein for the TLR family of proteins that has been implicated as a critical mediator of innate immune responses to pathogen detection. In this study, we report that MyD88 plays a crucial role in killing Gram-negative bacteria by primary macrophages via influencing NADPH oxidase function. Peritoneal macrophages from MyD88−/− mice exhibited a marked inability to kill Escherichia coli (F18) or an attenuated strain of Salmonella typhimurium (sseB) in vitro. This defect in killing was due to diminished NADPH oxidase-mediated production of superoxide anion in response to bacteria by MyD88−/− phagocytes as a consequence of defective NADPH oxidase assembly. Defective oxidase assembly in MyD88-deficient macrophages resulted from impaired p38 MAPK activation and subsequent phosphorylation of p47phox. Together these data demonstrate a pivotal role for MyD88 in killing Gram-negative bacteria via modulation of NADPH oxidase activity in phagocytic cells.

Published
2005

2. Cutting Edge: The Natural Ligand for Glucocorticoid-Induced TNF Receptor-Related Protein Abrogates Regulatory T Cell Suppression

Author

William A. Faubion, Cristina Cozzo, Cox Terhorst, Ana C. Abadía-Molina, F. Stephen Laroux, Hongbin Ji, Gongxian Liao, and Andrew J. Caton

Subjects
Regulatory T cell, Immunology, chemical and pharmacologic phenomena, Receptors, Nerve Growth Factor, Biology, Ligands, T-Lymphocytes, Regulatory, Receptors, Tumor Necrosis Factor, Cell Line, law.invention, Mice, Glucocorticoid-Induced TNFR-Related Protein, Adjuvants, Immunologic, T-Lymphocyte Subsets, law, medicine, Animals, Humans, Immunology and Allergy, Secretion, Receptor, Interphase, Clonal Anergy, Mice, Inbred BALB C, NF-kappa B, Receptors, Interleukin-2, hemic and immune systems, In vitro, Up-Regulation, Cell biology, medicine.anatomical_structure, Solubility, Cell culture, Tumor Necrosis Factors, Interleukin-2, Suppressor, Carrier Proteins, Cell Division, Glucocorticoid, Signal Transduction, medicine.drug
Abstract

CD4+25+ regulatory T (Treg) cells maintain immunological self-tolerance through mechanisms that are only in part understood. Previous studies suggest that the glucocorticoid-induced TNFR-related protein (GITR), which is preferentially expressed on the surface of Treg cells, potentially provides a signal that abrogates Treg suppression. In this study, we show that a soluble form of mouse GITR ligand (sGITR-L) induces GITR-dependent NF-κB activation and blocks in vitro suppression mediated by both resting and preactivated polyclonal and Ag-specific Treg cells. Since sGITR-L along with rIL-2 induces proliferation of CD4+25+ cells, it appears that sGITR-L can break the anergic state of Treg cells. Because sGITR-L also up-regulates IL-2 secretion by activated CD4+25 −T cells, these two sGITR-L induced signals synergize to interfere with suppressor activity by CD4+25+ Treg cells.

Published
2004

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