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Infection and Immunity

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https://www.readbyqxmd.com/read/28893919/antigen-localisation-influences-the-magnitude-and-kinetics-of-the-endogenous-adaptive-immune-response-to-recombinant-salmonella-vaccines
#1
Yanina R Sevastsyanovich, David R Withers, Claire L Marriott, Faye C Morris, Timothy J Wells, Douglas F Browning, Irene Beriotto, Ewan Ross, Hossam Omar Ali, Catherine A Wardius, Adam F Cunningham, Ian R Henderson, Amanda E Rossiter
The use of recombinant attenuated Salmonella vaccine (RASV) strains is a promising strategy to present heterologous antigens to the mammalian immune system to induce both cellular and humoral immune responses. However, studies on RASV development differ in where heterologous antigens are expressed and localised within the bacterium and it is unclear how antigen localisation modulates the immune response. Previously, we exploited the plasmid-encoded toxin (Pet) autotransporter system for accumulation of heterologous antigens in the cell culture supernatant...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893918/enterococcus-faecalis-promotes-innate-immune-suppression-and-polymicrobial-catheter-associated-urinary-tract-infection
#2
Brenda Yin Qi Tien, Hwee Mian Sharon Goh, Kelvin Kian Long Chong, Soumili Bhaduri-Tagore, Sarah Holec, Regine Dress, Florent Ginhoux, Molly A Ingersoll, Rohan B H Williams, Kimberly A Kline
Enterococcus faecalis, a member of the human gastrointestinal microbiota, is an opportunistic pathogen associated with hospital-acquired wound, bloodstream, and urinary tract infections. E. faecalis can subvert or evade immune-mediated clearance, although the mechanisms are poorly understood. In this study, we examined E. faecalis-mediated subversion of macrophage activation. We observed that E. faecalis actively prevents NF-κB signaling in mouse RAW264.7 macrophages in the presence of Toll-like receptor agonists and during polymicrobial infection with Escherichia coliE...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893917/phenol-soluble-modulin-peptides-contribute-to-influenza-associated-staphylococcus-aureus-pneumonia
#3
Dominik Alexander Bloes, Emanuel Haasbach, Carmen Hartmayer, Tobias Hertlein, Karin Klingel, Dorothee Kretschmer, Oliver Planz, Andreas Peschel
Influenza A virus (IAV) infections are often followed by secondary bacterial lung infection, which is a major reason for severe, often fatal pneumonia. Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains such as USA300 cause particularly severe and difficult-to-treat cases of IAV-associated pneumonia. CA-MRSA are known to produce extraordinarily high amounts of phenol-soluble modulin (PSM) peptides, important cytotoxins and proinflammatory molecules contributing to several types of S...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893916/the-role-of-activins-in-hepcidin-regulation-during-malaria
#4
Natasha Spottiswoode, Andrew E Armitage, Andrew R Williams, Alex J Fyfe, Sumi Biswas, Susanne H Hodgson, David Llewellyn, Prateek Choudhary, Simon J Draper, Patrick Duffy, Hal Drakesmith
Epidemiological observations have linked increased host iron with malaria susceptibility, and perturbed iron handling has been hypothesized to contribute to the potentially life threatening anemia that may accompany blood-stage malaria infection. To improve our understanding of these relationships, we examined the pathways involved in regulation of the master controller of iron metabolism, the hormone hepcidin, in malaria infection. We show that hepcidin upregulation in Plasmodium berghei murine malaria infection was accompanied by changes in expression of bone morphogenetic protein (BMP)/sons of mothers against decapentaplegic (SMAD) pathway target genes, a key pathway involved in hepcidin regulation...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893915/hyperbiofilm-formation-by-bordetella-pertussis-strains-correlates-with-enhanced-virulence-traits
#5
Natalia Cattelan, Jamie Jennings-Gee, Purnima Dubey, Osvaldo M Yantorno, Rajendar Deora
Pertussis or whooping cough caused by the obligate human pathogen Bordetella pertussis is undergoing a world-wide resurgence. Majority of studies with this pathogen are conducted with laboratory-adapted strains which may not be representative of the species as a whole. Biofilm formation by B. pertussis plays an important role in its pathogenesis. We conducted a side-by side comparison of the biofilm forming ability of the prototype laboratory strains with currently circulating isolates from two countries with different vaccination programs...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893914/stenotrophomonas-maltophilia-serine-protease-stmpr1-induces-matrilysis-anoikis-and-protease-activated-receptor-2-activation-in-human-lung-epithelial-cells
#6
Ashley L DuMont, Nicholas P Cianciotto
Stenotrophomonas maltophilia is an emerging, opportunistic nosocomial pathogen that can cause severe disease in immunocompromised individuals. We recently identified the StmPr1 and StmPr2 serine proteases as substrates of the Xps type II secretion system in S. maltophilia strain K279a. Here, we report that a third serine protease, StmPr3, is also secreted in an Xps-dependent manner. By constructing a panel of protease mutants in strain K279s, we were able to determine that StmPr3 contributes to the previously described Xps-mediated rounding and detachment of the A549 human lung epithelial cell line as well as Xps-mediated degradation of fibronectin, fibrinogen, and the cytokine interleukin-8...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893913/il17a-deficient-mice-are-highly-susceptible-to-toxoplasma-gondii-infection-due-to-excessively-induced-t-gondii-hsp70-and-ifn-%C3%AE-production
#7
Masataka Moroda, Masaya Takamoto, Yoichiro Iwakura, Jun Nakayama, Fumie Aosai
IL-17A is known to be involved in the host defense against pathogens and pathogenesis of autoimmune diseases. Previously, we showed that excessive IFN-γ plays an important role in the pathogenesis of lethal effect of Toxoplasma gondii (T. gondii) by inducing anaphylactic responses. In this report, we examine the effects of an IL-17A deficiency on murine host defense against oral T. gondii infection. IL-17A-deficient C57BL/6 (B6) mice exhibited higher mortality than wild type (WT) mice to T. gondii at the acute phase of infection...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28893912/the-gene-tia-harboured-by-the-se-pai-is-involved-in-the-ability-of-lee-negative-stec-strains-to-invade-monolayers-of-epithelial-cells
#8
Roslen Bondì, Paola Chiani, Valeria Michelacci, Fabio Minelli, Alfredo Caprioli, Stefano Morabito
LEE-negative Shiga toxin (Stx)-producing E. coli (STEC) are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia, previously described in ETEC strains, has been identified in LEE-negative STEC that possess the Subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia present in these LEE-negative STEC in the invasion of monolayers of cultured cells...
September 11, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28874447/salmonella-utilizes-zinc-to-subvert-anti-microbial-host-defense-of-macrophages-via-modulation-of-nf-%C3%AE%C2%BAb-signaling
#9
Aimin Wu, Piotr Tymoszuk, David Haschka, Simon Heeke, Stefanie Dichtl, Verena Petzer, Markus Seifert, Richard Hilbe, Sieghart Sopper, Heribert Talasz, Dirk Bumann, Cornelia Lass-Flörl, Igor Theurl, Keying Zhang, Guenter Weiss
Zinc sequestration by macrophages is considered a crucial host defense strategy against infection with the intracellular bacterium Salmonella Typhimurium. However, the underlying mechanisms remain elusive. In this study we found zinc to favor pathogen survival within macrophages. Salmonella-hosting macrophages contained higher free zinc levels than uninfected macrophages and cells that successfully eliminated bacteria, which was paralleled by impaired production of reactive oxygen (ROS) and nitrogen (RNS) species in bacteria-harboring cells...
September 5, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28874446/characterization-of-two-novel-lipopolysaccharide-phosphoethanolamine-transferases-in-pasteurella-multocida-and-their-role-in-resistance-to-cathelicidin-2
#10
Marina Harper, Amy Wright, Frank St Michael, Jianjun Li, Deanna Deveson Lucas, Mark Ford, Ben Adler, Andrew D Cox, John D Boyce
The lipopolysaccharide (LPS) produced by the Gram-negative bacterial pathogen Pasteurella multocida has phosphoethanolamine (PEtn) residues attached to lipid A, 3-deoxy-D-manno-octulosonic acid (Kdo), heptose and galactose. In this study, we show that PEtn is transferred to lipid A by the P. multocida EptA homologue, PetL, and is transferred to galactose by a novel PEtn transferase that is unique to P. multocida called PetG. Transcriptomic analyses indicated that petL expression was positively regulated by the global regulator Fis and negatively regulated by an Hfq-dependent small RNA...
September 5, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28874445/ifn-%C3%AE-mediates-experimental-cerebral-malaria-by-signalling-within-both-the-hematopoietic-and-non-hematopoietic-compartments
#11
Ana Villegas-Mendez, Patrick Strangward, Tovah N Shaw, Ivana Rajkovic, Vinko Tosevski, Ruth Forman, Werner Muller, Kevin N Couper
Experimental cerebral malaria (ECM) is an IFN-γ dependent syndrome. However, whether IFN-γ promotes ECM through direct and synergistic targeting of multiple cell populations or whether it causes ECM through acting primarily on a specific responsive cell type, is currently unknown. Here, using a panel of cell and compartment-specific IFN- γR2 deficient mice, we show that IFN-γ causes ECM by signalling within both the hematopoietic and non-haematopoietic compartments. Mechanistically, hematopoietic and non-haematopoietic compartment-specific IFN-γR signalling exerts additive effects in orchestrating intracerebral inflammation leading to ECM development...
September 5, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28874444/modulation-of-cd4-and-cd8-t-cell-function-and-cytokine-responses-in-strongyloides-stercoralis-infection-by-il-27-and-il-37
#12
Rajamanickam Anuradha, Saravanan Munisankar, Yukthi Bhootra, Chandrakumar Dolla, Paul Kumaran, Thomas B Nutman, Subash Babu
Strongyloides stercoralis (Ss) infection is associated with diminished antigen - specific Th1- and Th17-associated responses and enhanced Th2-associated responses. IL-27 and IL-37 are 2 known anti-inflammatory cytokines that are highly expressed in Ss infection. We, therefore wanted to examine the role of IL-27 and IL-37 in regulating CD4(+) and CD8(+) T cell responses in Ss infection. To this end, we examined the frequency of Th1/Tc1, Th2/Tc2, Th9/Tc9, Th17/Tc17 and Th22/Tc22 cells in 15 Ss- infected individuals and 10 uninfected individuals, stimulated with parasite antigen following IL-27 or IL-37 neutralization...
September 5, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28847850/induction-of-type-i-interferon-through-a-non-canonical-toll-like-receptor-7-pathway-during-yersinia-pestis-infection
#13
Miqdad O Dhariwala, Rachel M Olson, Deborah M Anderson
Yersinia pestis causes bubonic, pneumonic and septicemic plague, diseases that are rapidly lethal to most mammals, including humans. Plague develops as a consequence of bacterial neutralization of the host's innate immune response, which permits uncontrolled growth and causes the systemic hyperactivation of the inflammatory response. We previously found that host type I interferon (IFN) signaling is induced during Y. pestis infection and contributes to neutrophil depletion and disease. In this work, we show that type I IFN expression is derived from the recognition of intracellular Y...
August 28, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28847849/otitis-media-and-nasopharyngeal-colonization-in-ccl3-mice
#14
Dominik Deniffel, Brian Nuyen, Kwang Pak, Keigo Suzukawa, Jun Hung, Arwa Kurabi, Stephen I Wasserman, Allen F Ryan
Introduction. We previously found CC chemokine ligand 3 (CCL3) to be a potent effector of inflammation during otitis media (OM): exogenous CCL3 rescues the OM phenotype of tumor necrosis factor-deficient mice, and function of macrophages deficient in several innate immune molecules. To further delineate the role of CCL3 in OM, we evaluated middle ear (ME) responses of ccl3(-/-) mice to nontypeable Haemophilus influenzae (NTHi).Materials and Methods. CCL chemokine gene expression was evaluated in wildtype (WT) mice during the complete course of acute OM...
August 28, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28847848/candida-and-pseudomonas-interact-to-enhance-virulence-of-mucosal-infection-in-transparent-zebrafish
#15
Audrey C Bergeron, Brittany G Seman, John H Hammond, Linda S Archambault, Deborah A Hogan, Robert T Wheeler
Polymicrobial infections often include both fungi and bacteria, and can complicate patient treatment and resolution of infection. Cross-kingdom interactions among bacteria, fungi, and/or the immune system during infection can enhance or block virulence mechanisms and influence disease progression. The fungus C. albicans and the bacterium P. aeruginosa are co-isolated in the context of polymicrobial infection at a variety of sites throughout the body, including mucosal tissues such as the lung. In vitro,C. albicans and P...
August 28, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28827366/spontaneous-virulence-loss-in-natural-populations-of-listeria-monocytogenes
#16
Mylène M Maury, Viviane Chenal-Francisque, Hélène Bracq-Dieye, Lei Han, Alexandre Leclercq, Guillaume Vales, Alexandra Moura, Edith Gouin, Mariela Scortti, Olivier Disson, José A Vázquez-Boland, Marc Lecuit
Listeria monocytogenes (Lm) pathogenesis depends on its ability to escape from the phagosome of the host cells via the action of the pore-forming toxin listeriolysin O (LLO). Expression of the LLO-encoding gene (hly) requires the transcriptional activator PrfA, and both hly and prfA genes are essential for Lm virulence. Here we used the hemolytic activity of LLO as a phenotypic marker to screen for spontaneous virulence-attenuating mutations in Lm Sixty (0.1%) non-hemolytic isolates were identified among a collection of 57,820 confirmed Lm strains isolated from a variety of sources...
August 21, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808163/a-role-for-fimh-in-extraintestinal-pathogenic-escherichia-coli-invasion-and-translocation-through-the-intestinal-epithelium
#17
Nina M Poole, Sabrina I Green, Anubama Rajan, Luz E Vela, Xi-Lei Zeng, Mary K Estes, Anthony W Maresso
The translocation of bacteria across the intestinal epithelium of immunocompromised patients can lead to bacteremia and life-threatening sepsis. Extraintestinal Pathogenic Escherichia coli (ExPEC), so named because this pathotype infects tissues distal to the intestinal tract, is a frequent cause of such infections, is often multidrug resistant, and chronically colonizes a sizable portion of the healthy population. Although several virulence factors and their roles in pathogenesis are well described for ExPEC that cause urinary tract infections and meningitis, they have not been linked to translocation through intestinal barriers, a fundamentally distant yet important clinical phenomenon...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808162/listeria-monocytogenes-and-shigella-flexneri-activate-the-nlrp1b-inflammasome
#18
Jana Neiman-Zenevich, Sarah Stuart, Mena Abdel-Nour, Stephen E Girardin, Jeremy Mogridge
Activation of the innate immune receptor NLRP1B leads to the formation of an inflammasome, which induces autoproteolytic processing of pro-caspase-1, and ultimately to the release of inflammatory cytokines and to the execution of pyroptosis. One of the signals to which NLRP1B responds is metabolic stress that occurs in cells deprived of glucose or treated with metabolic inhibitors. NLRP1B might, therefore, sense microbial infection as intracellular pathogens such as Listeria monocytogenes and Shigella flexneri cause metabolic stress as a result of nutrient scavenging and host cell damage...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808161/listeria-monocytogenes-has-both-a-bd-type-and-an-aa3-type-terminal-oxidase-which-allow-growth-in-different-oxygen-levels-and-both-are-important-in-infection
#19
David Corbett, Marie Goldrick, Vitor E Fernandes, Kelly Davidge, Robert K Poole, Peter W Andrew, Jennifer Cavet, Ian S Roberts
Listeria monocytogenes is a food borne pathogen responsible for a number of life-threatening infections of humans. During an infection it invades epithelial cells before spreading from the intestine to the cells of the liver and spleen. This requires an ability to adapt to varying oxygen levels. Here we demonstrate that L. monocytogenes has two terminal oxidases, a cytochrome bd-type (CydAB) and a cytochrome aa3 -type menaquinol oxidase (QoxAB) and that both are used for respiration under different oxygen tensions...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808160/incremental-contributions-of-fbaa-and-other-impetigo-associated-surface-proteins-to-fitness-and-virulence-of-a-classical-group-a-streptococcal-skin-strain
#20
Candace N Rouchon, Anhphan T Ly, John P Noto, Feng Luo, Sergio Lizano, Debra E Bessen
Group A streptococci (GAS) are highly prevalent human pathogens whose primary ecological niche is the superficial epithelial layers of the throat and/or skin. Many GAS strains having a strong tendency to cause pharyngitis are distinct from strains that tend to cause impetigo; thus, genetic differences between them may confer host tissue-specific virulence. In this study, the FbaA surface protein gene is found to be present in most skin specialist strains, but largely absent from a genetically-related subset of pharyngitis isolates...
August 14, 2017: Infection and Immunity
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