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Superantigen

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https://www.readbyqxmd.com/read/28742082/bacterial-deception-of-mait-cells-in-a-cloud-of-superantigen-and-cytokines
#1
Johan K Sandberg, Anna Norrby-Teglund, Edwin Leeansyah
The bacterium Staphylococcus aureus is an important cause of the life-threatening condition toxic shock syndrome in humans. Bacterial toxins known as superantigens (SAgs) generate this illness by acting as broad activators of a substantial fraction of all T lymphocytes, bypassing the normally highly stringent T-cell receptor antigen specificity to cause a systemic inflammatory cytokine storm in the host. In a new study, Shaler et al. found that immune cells called mucosa-associated invariant T (MAIT) cells make an unexpectedly large contribution to the SAg response in a largely T-cell receptor-independent, cytokine-driven manner...
July 24, 2017: PLoS Biology
https://www.readbyqxmd.com/read/28736763/immunologic-effects-of-maraviroc-in-hiv-infected-patients-with-severe-cd4-lymphopenia-starting-antiretroviral-therapy-a-sub-study-of-the-cadiris-trial
#2
Pablo F Belaunzarán-Zamudio, Livio Azzoni, David H Canaday, Yanink N Caro-Vega, Brian Clagget, Mohammed S Rassool, Benigno Rodriguez, Ian Sanne, Irini Sereti, Juan G Sierra-Madero, Michael M Lederman
BACKGROUND: We aimed to describe the mechanisms of immunological recovery and the effects of blocking CCR5 in patients starting ART with advanced HIV-infection. METHODS: This was a sub-study of a 48 week double-blind, clinical trial where patients starting ART with CD4+ cell counts <100 cells/uL were randomized to receive maraviroc or a placebo. CD4+ and CD8+ cell maturation phenotypes, expression of PD-1 and CCR5, and activation indices were measured at weeks 0, 4, 12, 24, and 48...
2017: Pathogens & Immunity
https://www.readbyqxmd.com/read/28734577/characterization-of-a-pvl-negative-community-acquired-methicillin-resistant-staphylococcus-aureus-strain-of-sequence-type-88-in-china
#3
Lu Sun, Dandan Wu, Yan Chen, Qian Wang, Haiping Wang, Yunsong Yu
Sequence type 88 community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strain SR434, isolated from an outpatient with skin and soft tissue infection, was subjected to whole genome sequencing, antimicrobial susceptibility testing, mouse skin infection model and hemolysis analysis to identify its virulence and resistance determinants. MRSA strain SR434 is resistant to clindamycin, erythromycin and fosfomycin. Four plasmids with resistance genes were identified in this strain, including a 20,658bp blaZ-carrying plasmid, a 2473bp ermC-carrying plasmid, a 2622bp fosB7-carrying plasmid (86% identity with plasmid in a ST2590 MRSA strain) and a 4817bp lnuA-carrying plasmid (99% identity with pLNU4 from bovine coagulase-nagetive Staphylococci)...
July 13, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28719668/epidemiology-and-distribution-of-10-superantigens-among-invasive-streptococcus-pyogenes-disease-in-germany-from-2009-to-2014
#4
Matthias Imöhl, Christina Fitzner, Stephanie Perniciaro, Mark van der Linden
A nationwide laboratory-based surveillance study of invasive S. pyogenes infections was conducted in Germany. Invasive isolates (n = 719) were obtained between 2009 and 2014. Most isolates were obtained from blood (92.1%). The proportions of isolates from cerebrospinal fluid, pleural fluid, synovial fluid and peritoneal fluid were 3.9%, 1.8%, 1.7% and 0.6%, respectively. The most common emm types were emm 1 (31.8%), emm 28 (15.4%) and emm 89 (14.5%). The most common superantigen genes (speA, speC, speG, speH, speI, speJ, speK, speL, speM, ssa) identified from S...
2017: PloS One
https://www.readbyqxmd.com/read/28715277/superantigen-staphylococcal-enterotoxin-c1-inhibits-the-growth-of-bladder-cancer
#5
Tao Liu, Lin Li, Lei Yin, Hongyuan Yu, Hongwei Jing, Yang Liu, Chuize Kong, Mingkai Xu
Superantigens can induce cell-mediated cytotoxicity preferentially against MHC II-positive target cells with large amounts of inflammatory cytokines releasing. In this study, superantigen staphylococcal enterotoxin C (SEC) 1 was investigated to evaluate its potential in bladder cancer immunotherapy in vitro and in vivo. Our results revealed that SEC1 could stimulate the proliferation of human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner, accompanied with the release of interleukin-2, interferon-γ, and tumor necrosis factor-α, and increased the population of CD4(+) T cells and CD8(+) T cells...
July 17, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28683848/role-of-local-allergic-inflammation-and-staphylococcus-aureus-enterotoxins-in-chinese-patients-with-chronic-rhinosinusitis-with-nasal-polyps
#6
K-J Cheng, Y-Y Xu, M-L Zhou, S-H Zhou, S-Q Wang
OBJECTIVE: To investigate the role of local allergic inflammation and Staphylococcus aureus enterotoxins in chronic rhinosinusitis with nasal polyps. METHODS: This study included 36 patients with chronic rhinosinusitis with nasal polyps and 18 controls. Total immunoglobulin E, eosinophil cationic protein, staphylococcal enterotoxin types A and B specific immunoglobulin E, staphylococcal enterotoxin types A and B, and myeloperoxidase levels were determined. RESULTS: Four patients with chronic rhinosinusitis with nasal polyps had a local allergy...
July 7, 2017: Journal of Laryngology and Otology
https://www.readbyqxmd.com/read/28680421/an-emm5-group-a-streptococcal-outbreak-among-workers-in-a-factory-manufacturing-telephone-accessories
#7
Mingliang Chen, Wenqing Wang, Lihong Tu, Yaxu Zheng, Hao Pan, Gangyi Wang, Yanxin Chen, Xi Zhang, Linying Zhu, Jian Chen, Min Chen
Ranked among the top10 infectious causes of death worldwide, group A Streptococcus (GAS) causes small- and large-scale outbreaks, depending on the trigger as transmission of a GAS strain or expansion of predominant clones. In China, GAS infections other than scarlet fever are not notifiable. In Shanghai, an epidemiological investigation was initiated after two successive severe pneumonia cases with one death in a digital factory, from where outbreaks are less widely reported. The investigation was performed using emm typing, pulsed-field gel electrophoresis (PFGE) typing, superantigen profiling, and genome analysis...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28653102/identification-of-set11-from-staphylococcus-aureus-mu50-strain-as-a-ortholog-of-ssl7-via-bioinformatic-analysis-and-determination-of-its-possible-targets-from-human-serum-using-cnbr-pull-down-assays
#8
Ying Li, Xiaobao Chen, Nan Jia, Xuan Zhang, Jianye Zang
OBJECTIVES: To identify and characterize staphylococcus exotoxin-like (SET) protein Set11 from Staphylococcus aureus Mu50 strain and its possible targets proteins from human blood/serum. RESULTS: Set11 is a member of the staphylococcal superantigen-like (SSL) proteins (also called Staphylococcus exotoxin-like (SET) proteins) family that is found in staphylococcal strain Mu50. Its structure and function, however, remain unknown. We performed bioinformatics analysis of Set11: it had 90% sequence identity to SSL7 in NCTC 8325 strain, indicating Set11 is a SSL7 ortholog...
June 26, 2017: Biotechnology Letters
https://www.readbyqxmd.com/read/28646491/sickle-cells-produce-functional-immune-modulators-and-cytotoxics
#9
Chiao-Wang Sun, Li-Chen Wu, Peter L Knopick, David S Bradley, Tim Townes, David S Terman
Sickle erythrocytes' (SSRBCs) unique physical adaptation to hypoxic conditions renders them able to home to hypoxic tumor niches in vivo, shut down tumor blood flow and induce tumoricidal responses. SSRBCs are also useful vehicles for transport of encapsulated drugs and oncolytic virus into hypoxic tumors with enhanced anti-tumor effects. In search of additional modes for arming sickle cells with cytotoxics, we turned to a lentiviral β-globin vector with optimized Locus Control Region/β-globin coding region/promoter/enhancers...
June 24, 2017: American Journal of Hematology
https://www.readbyqxmd.com/read/28642756/high-prevalence-of-macrolide-resistance-and-molecular-characterization-of-streptococcus-pyogenes-isolates-circulating-in-china-from-2009-to-2016
#10
Binghuai Lu, Yujie Fang, Yanyan Fan, Xingchun Chen, Junrui Wang, Ji Zeng, Yi Li, Zhijun Zhang, Lei Huang, Hongxia Li, Dong Li, Fengxia Zhu, Yanchao Cui, Duochun Wang
Streptococcus pyogenes, or group A Streptococcus, is a pathogen responsible for a wide range of clinical manifestations, from mild skin and soft tissue infections and pharyngitis to severe diseases. Its epidemiological characteristics should be comprehensively under surveillance for regulating the national prevention and treatment practice. Herein, a total of 140 S. pyogenes, including 38 invasive and 102 noninvasive isolates, were collected from infected patients in 10 tertiary general hospitals from 7 cities/provinces in China during the years 2009-2016...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28633740/parvovirus-b19-infection-in-an-adult-presenting-with-connective-tissue-disease-like-symptoms-a-report-of-the-clinical-and-histological-findings
#11
J E Liles, S C Shalin, B A White, L B Trigg, J R Kaley
Parvovirus B19 infections in adults are usually associated with nonspecific and mild symptoms. However, cases presenting with a lupus-like syndrome have been described, leading to the hypothesis that parvovirus infection can induce connective tissue disease. Various histopathologic features of cutaneous manifestations of parvovirus have been reported, including features which overlap with those of connective tissue disease. Herein, we discuss an unusual case of Parvovirus  B19 infection in a middle-aged woman...
June 15, 2017: Dermatology Online Journal
https://www.readbyqxmd.com/read/28632753/mait-cells-launch-a-rapid-robust-and-distinct-hyperinflammatory-response-to-bacterial-superantigens-and-quickly-acquire-an-anergic-phenotype-that-impedes-their-cognate-antimicrobial-function-defining-a-novel-mechanism-of-superantigen-induced-immunopathology
#12
Christopher R Shaler, Joshua Choi, Patrick T Rudak, Arash Memarnejadian, Peter A Szabo, Mauro E Tun-Abraham, Jamie Rossjohn, Alexandra J Corbett, James McCluskey, John K McCormick, Olivier Lantz, Roberto Hernandez-Alejandro, S M Mansour Haeryfar
Superantigens (SAgs) are potent exotoxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They target a large fraction of T cell pools to set in motion a "cytokine storm" with severe and sometimes life-threatening consequences typically encountered in toxic shock syndrome (TSS). Given the rapidity with which TSS develops, designing timely and truly targeted therapies for this syndrome requires identification of key mediators of the cytokine storm's initial wave. Equally important, early host responses to SAgs can be accompanied or followed by a state of immunosuppression, which in turn jeopardizes the host's ability to combat and clear infections...
June 2017: PLoS Biology
https://www.readbyqxmd.com/read/28624612/human-mast-cells-present-antigen-to-autologous-cd4-t-cells
#13
Sahar Lotfi-Emran, Brant R Ward, Quang T Le, Andrea L Pozez, Masoud H Manjili, Judith Woodfolk, Lawrence B Schwartz
BACKGROUND: Mast cells (MCs), the primary effector cell of the atopic response, participate in immune defense at host/environment interfaces, yet the mechanisms by which they interact with CD4(+)-T cells has been controversial. OBJECTIVE: We utilize in situ-matured primary human MCs and matched CD4(+)-T cells to diligently assess the ability of MCs to act as antigen-presenting cells. METHODS: We examined mature human skin-derived MCs by flow cytometry for expression of antigen-presenting molecules; for their ability to stimulate CD4(+)-T cells to express CD25 and proliferate when exposed to superantigen or to CMV antigen using matched T cells and MCs from CMV seropositive or seronegative donors; and for uptake of antigens...
June 14, 2017: Journal of Allergy and Clinical Immunology
https://www.readbyqxmd.com/read/28602067/bacterial-ball-as-an-unusual-finding-in-patients-with-chronic-rhinosinusitis
#14
Dong-Kyu Kim, Young Chan Wi, Su-Jin Shin, Youn Il Jang, Kyung Rae Kim, Seok Hyun Cho
Objectives: Pathophysiology of chronic rhinosinusitis (CRS) is very complex and has not yet been clearly understood. To date, various factors have been researched to have relations with the pathogenesis of CRS, such as superantigens and biofilms. Recently, we found an unusual pathological finding in patients with CRS, and we called this new entity as bacteria ball (or bioball). In this study, we analyze the clinical characteristics of bacteria ball occurred in CRS. Methods: This study enrolled consecutive 247 patients with CRS who underwent functional endoscopic sinus surgery from January 2015 to August 2016...
June 6, 2017: Clinical and Experimental Otorhinolaryngology
https://www.readbyqxmd.com/read/28581897/mutations-to-cysteine-residues-in-the-trypanosoma-cruzi-b-cell-superantigen-tc24-diminish-susceptibility-to-igm-mediated-hydrolysis
#15
Eric Luis Brown, Sarah Gunter, Kathryn M Jones, Christopher Seid, Heather T Essigmann, Maria Elena Bottazzi, Peter J Hotez, Bin Zhan, Ulrich Strych
B-cell superantigens (BC-SAgs) are immunoevasins that have evolved in response to innate catalytic IgM antibodies; germ-line encoded immunoglobulins present in the preimmune repertoire independent of prior antigen exposure. Catalysis is the result of a 2-step process that involves the formation of a non-covalent bond between the BC-SAg and the immunoglobulin first followed by covalent bond formation at the catalytic site resulting in target hydrolysis. Tc24 is a recently described Trypanosoma cruzi BC-SAg hypothesized to play a role in evading the humoral response early in the infection period...
June 5, 2017: Journal of Parasitology
https://www.readbyqxmd.com/read/28573424/vitamin-d-inhibits-the-staphylococcal-enterotoxin-b-induced-expression-of-tumor-necrosis-factor-in-microglial-cells
#16
Jinggui He, Xiyun Guo, Zhi-Qiang Liu, Ping-Chang Yang, Shaobo Yang
Microglial cells play a crucial role in inflammatory responses in neural tissue. Vitamin D (VitD3) deficiency is associated with the pathogenesis of inflammation. Staphylococcal enterotoxin B (SEB) is a superantigen and can initiate inflammation. This study tests a hypothesis that VitD3 deficiency upregulates the expression of tumor necrosis factor (TNF) in microglial cells. Microglial cells were isolated from the mouse brain. The microglial cells were cultured in the presence or absence of VitD3 or/and SEB...
June 1, 2017: Immunologic Research
https://www.readbyqxmd.com/read/28567041/pathogen-reactive-t-helper-cell-analysis-in-the-pig
#17
Friederike Ebner, Patrycja Schwiertz, Svenja Steinfelder, Robert Pieper, Jürgen Zentek, Nicole Schütze, Christoph G Baums, Gottfried Alber, Peter Geldhof, Susanne Hartmann
There is growing interest in studying host-pathogen interactions in human-relevant large animal models such as the pig. Despite the progress in developing immunological reagents for porcine T cell research, there is an urgent need to directly assess pathogen-specific T cells-an extremely rare population of cells, but of upmost importance in orchestrating the host immune response to a given pathogen. Here, we established that the activation marker CD154 (CD40L), known from human and mouse studies, identifies also porcine antigen-reactive CD4(+) T lymphocytes...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28561911/biofilm-formation-and-virulence-factor-analysis-of-staphylococcus-aureus-isolates-collected-from-ovine-mastitis
#18
E Azara, C Longheu, G Sanna, S Tola
AIMS: To perform a phenotypic and genotypic characterization of 258 Staphylococcus aureus isolates from clinical ovine mastitis and used for the preparation of inactivated autogenous vaccines. METHODS AND RESULTS: The potential for biofilm production was determined by phenotypic test of Congo Red Agar (CRA) and by PCR for the detection of icaA/D genes. Isolates were also screened by PCR for the presence of enterotoxins (sea, seb, sec, sed and see), toxic shock syndrome toxin (tsst), leukotoxins (lukD-E, lukM and lukPV83), haemolysins (hly-β and hly-γ), autolysin (atlA) genes and encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs: clfA, clfB, fnbA, fnbB, bbp, cna, eno, fib, epbs, sdrC, sdrD and SdrE)...
May 31, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28512627/laboratory-mice-are-frequently-colonized-with-staphylococcus-aureus-and-mount-a-systemic-immune-response-note-of-caution-for-in-vivo-infection-experiments
#19
Daniel Schulz, Dorothee Grumann, Patricia Trübe, Kathleen Pritchett-Corning, Sarah Johnson, Kevin Reppschläger, Janine Gumz, Nandakumar Sundaramoorthy, Stephan Michalik, Sabine Berg, Jens van den Brandt, Richard Fister, Stefan Monecke, Benedict Uy, Frank Schmidt, Barbara M Bröker, Siouxsie Wiles, Silva Holtfreter
Whether mice are an appropriate model for S. aureus infection and vaccination studies is a matter of debate, because they are not considered as natural hosts of S. aureus. We previously identified a mouse-adapted S. aureus strain, which caused infections in laboratory mice. This raised the question whether laboratory mice are commonly colonized with S. aureus and whether this might impact on infection experiments. Publicly available health reports from commercial vendors revealed that S. aureus colonization is rather frequent, with rates as high as 21% among specific-pathogen-free mice...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28497030/fda-approved-immunosuppressants-targeting-staphylococcal-superantigens-mechanisms-and-insights
#20
REVIEW
Teresa Krakauer
Immunostimulating staphylococcal enterotoxin B (SEB) and related superantigenic toxins cause diseases in human beings and laboratory animals by hyperactivating cells of the immune system. These protein toxins bind to the major histocompatibility complex class II (MHC II) molecules and specific Vβ regions of T-cell receptors (TCRs), resulting in the stimulation of both monocytes/macrophages and T lymphocytes. The bridging of TCR with MHC II molecules by superantigens triggers intracellular signaling cascades, resulting in excessive release of proinflammatory mediators and massive polyclonal T-cell proliferation...
2017: ImmunoTargets and Therapy
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