scholarly journals Transient Suppression of Shigella flexneri Type 3 Secretion by a Protective O-Antigen-Specific Monoclonal IgA

mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Stephen J. Forbes ◽  
Tia Bumpus ◽  
Elizabeth A. McCarthy ◽  
Blaise Corthésy ◽  
Nicholas J. Mantis
Keyword(s):  
Epithelial Cells ◽  
Mucosal Immunity ◽  
Intestinal Epithelial Cells ◽  
Shigella Flexneri ◽  
Secretory Iga ◽  
Bacterial Invasion ◽  
Intestinal Epithelial ◽  
Content Type ◽  
O Antigen ◽  
Type 3

ABSTRACTMucosal immunity to the enteric pathogenShigella flexneriis mediated by secretory IgA (S-IgA) antibodies directed against the O-antigen (O-Ag) side chain of lipopolysaccharide. While secretory antibodies against the O-Ag are known to prevent bacterial invasion of the intestinal epithelium, the mechanisms by which this occurs are not fully understood. In this study, we report that the binding of a murine monoclonal IgA (IgAC5) to the O-Ag ofS. flexneriserotype 5a suppresses activity of the type 3 secretion (T3S) system, which is necessary forS. flexnerito gain entry into intestinal epithelial cells. IgAC5’s effects on the T3S were rapid (5 to 15 min) and were coincident with a partial reduction in the bacterial membrane potential and a decrease in intracellular ATP levels. Activity of the T3S system returned to normal levels 45 to 90 min following antibody treatment, demonstrating that IgAC5’s effects were transient. Nonetheless, these data suggest a model in which the association of IgA with the O-Ag ofS. flexneripartially de-energizes the T3S system and temporarily renders the bacterium incapable of invading intestinal epithelial cells.IMPORTANCESecretory IgA (S-IgA) serves as the first line of defense against enteric infections. However, despite its well-recognized role in mucosal immunity, relatively little is known at the molecular level about how this class of antibody functions to prevent pathogenic bacteria from penetrating the epithelial barrier. It is generally assumed that S-IgA functions primarily by “immune exclusion,” a phenomenon in which the antibody binds to microbial surface antigens and thereby promotes bacterial agglutination, entrapment in mucus, and physical clearance from the gastrointestinal tract via peristalsis. The results of the present study suggest that in addition to serving as a physical barrier, S-IgA may have a direct impact on the ability of microbial pathogens to secrete virulence factors required for invasion of intestinal epithelial cells.

scholarly journals Agglutinating Secretory IgA Preserves Intestinal Epithelial Cell Integrity during Apical Infection by Shigella flexneri

2013 ◽  
Vol 81 (8) ◽  
pp. 3027-3034 ◽  
Author(s):  
Amandine Mathias ◽  
Stéphanie Longet ◽  
Blaise Corthésy
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Nuclear Translocation ◽  
Inflammatory Responses ◽  
Shigella Flexneri ◽  
Indirect Evidence ◽  
Secretory Iga ◽  
Intestinal Epithelial ◽  
Cell Integrity ◽  
Content Type

ABSTRACTShigella flexneri, by invading intestinal epithelial cells (IECs) and inducing inflammatory responses of the colonic mucosa, causes bacillary dysentery. Although M cells overlying Peyer's patches are commonly considered the primary site of entry ofS. flexneri, indirect evidence suggests that bacteria can also use IECs as a portal of entry to the lamina propria. Passive delivery of secretory IgA (SIgA), the major immunoglobulin secreted at mucosal surfaces, has been shown to protect rabbits from experimental shigellosis, but no information exists as to its molecular role in maintaining luminal epithelial integrity. We have established that the interaction of virulentS. flexneriwith the apical pole of a model intestinal epithelium consisting of polarized Caco-2 cell monolayers resulted in the progressive disruption of the tight junction network and actin depolymerization, eventually resulting in cell death. The lipopolysaccharide (LPS)-specific agglutinating SIgAC5 monoclonal antibody (MAb), but not monomeric IgAC5 or IgGC20 MAbs of the same specificity, achieved protective functions through combined mechanisms, including limitation of the interaction betweenS. flexneriand epithelial cells, maintenance of the tight junction seal, preservation of the cell morphology, reduction of NF-κB nuclear translocation, and inhibition of proinflammatory mediator secretion. Our results add to the understanding of the function of SIgA-mediated immune exclusion by identifying a mode of action whereby the formation of immune complexes translates into maintenance of the integrity of epithelial cells lining the mucosa. This novel mechanism of protection mediated by SIgA is important to extend the arsenal of effective strategies to fight againstS. flexnerimucosal invasion.

scholarly journals Association of a Protective Monoclonal IgA with the O Antigen of Salmonella enterica Serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity

2012 ◽  
Vol 80 (7) ◽  
pp. 2454-2463 ◽  
Author(s):  
Stephen J. Forbes ◽  
Daniel Martinelli ◽  
Chyongere Hsieh ◽  
Jeffrey G. Ault ◽  
Michael Marko ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Integrity ◽  
Effector Proteins ◽  
Content Type ◽  
O Antigen ◽  
Serovar Typhimurium ◽  
Type 3

ABSTRACTInvasion of intestinal epithelial cells bySalmonella entericaserovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as theSalmonellapathogenicity island 1 (SPI-1) type 3 secretion system (T3SS). By a mechanism that remains poorly understood, entry ofS. Typhimurium into epithelial cells is inhibited by Sal4, a monoclonal, polymeric IgA antibody that binds an immunodominant epitope within the O-antigen (O-Ag) component of lipopolysaccharide. In this study, we investigated how the binding of Sal4 to the surface ofS. Typhimurium influences T3SS activity, bacterial energetics, and outer membrane integrity. We found that Sal4 treatment impaired T3SS-mediated translocon formation and attenuated the delivery of tagged effector proteins into epithelial cells. Sal4 treatment coincided with a partial reduction in membrane energetics and intracellular ATP levels, possibly explaining the impairment in T3SS activity. Sal4's effects on bacterial secretion and energetics occurred concurrently with an increase in O-Ag levels in culture supernatants, alterations in outer membrane permeability, and changes in surface ultrastructure, as revealed by transmission electron microscopy and cryo-electron microscopy. We propose that Sal4, by virtue of its ability to bind and cross-link the O-Ag, induces a form of outer membrane stress that compromises the integrity of theS. Typhimurium cell envelope and temporarily renders the bacterium avirulent.

scholarly journals Dual Recognition of Sialic Acid and αGal Epitopes by the VP8* Domains of the Bovine Rotavirus G6P[5] WC3 and of Its Mono-reassortant G4P[5] RotaTeq Vaccine Strains

2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Mia Madel Alfajaro ◽  
Ji-Yun Kim ◽  
Laure Barbé ◽  
Eun-Hyo Cho ◽  
Jun-Gyu Park ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Blood Group ◽  
Intestinal Epithelial Cells ◽  
Sialic Acids ◽  
Blood Group Antigens ◽  
Intestinal Epithelial ◽  
Content Type ◽  
Group A Rotaviruses ◽  
Group A ◽  
Small Intestinal

ABSTRACTGroup A rotaviruses, an important cause of severe diarrhea in children and young animals, initiate infection via interactions of the VP8* domain of the VP4 spike protein with cell surface sialic acids (SAs) or histo-blood group antigens (HBGAs). Although the bovine G6P[5] WC3 strain is an important animal pathogen and is also used in the bovine-human reassortant RotaTeq vaccine, the receptor(s) for the VP8* domain of WC3 and its reassortant strains have not yet been identified. In the present study, HBGA- and saliva-binding assays showed that both G6P[5] WC3 and mono-reassortant G4P[5] strains recognized the αGal HBGA. The infectivity of both P[5]-bearing strains was significantly reduced in αGal-free MA-104 cells by pretreatment with a broadly specific neuraminidase or by coincubation with the α2,6-linked SA-specificSambucus nigralectin, but not by the α2,3-linked specific sialidase or byMaackia amurensislectin. Free NeuAc and the αGal trisaccharide also prevented the infectivity of both strains. This indicated that both P[5]-bearing strains utilize α2,6-linked SA as a ligand on MA104 cells. However, the two strains replicated in differentiated bovine small intestinal enteroids and in their human counterparts that lack α2,6-linked SA or αGal HBGA, suggesting that additional or alternative receptors such as integrins, hsp70, and tight-junction proteins bound directly to the VP5* domain can be used by the P[5]-bearing strains to initiate the infection of human cells. In addition, these data also suggested that P[5]-bearing strains have potential for cross-species transmission.IMPORTANCEGroup A rotaviruses initiate infection through the binding of the VP8* domain of the VP4 protein to sialic acids (SAs) or histo-blood group antigens (HBGAs). Although the bovine G6P[5] WC3 strain is an important animal pathogen and is used as the backbone in the bovine-human reassortant RotaTeq vaccine, the receptor(s) for their P[5] VP8* domain has remained elusive. Using a variety of approaches, we demonstrated that the WC3 and bovine-human mono-reassortant G4P[5] vaccine strains recognize both α2,6-linked SA and αGal HBGA as ligands. Neither ligand is expressed on human small intestinal epithelial cells, explaining the absence of natural human infection by P[5]-bearing strains. However, we observed that the P[5]-bearing WC3 and G4P[5] RotaTeq vaccine strains could still infect human intestinal epithelial cells. Thus, the four P[5] RotaTeq vaccine strains potentially binding to additional alternative receptors may be efficient and effective in providing protection against severe rotavirus disease in human.

scholarly journals Interleukin-7 Produced by Intestinal Epithelial Cells in Response to Citrobacter rodentium Infection Plays a Major Role in Innate Immunity against This Pathogen

2015 ◽  
Vol 83 (8) ◽  
pp. 3213-3223 ◽  
Author(s):  
Wei Zhang ◽  
Jiang-Yuan Du ◽  
Qing Yu ◽  
Jun-O Jin
Keyword(s):  
Epithelial Cells ◽  
Protective Immunity ◽  
Bacterial Infections ◽  
Intestinal Epithelial Cells ◽  
Intestinal Damage ◽  
Intestinal Epithelial ◽  
Citrobacter Rodentium ◽  
Content Type ◽  
Interleukin 7

Interleukin-7 (IL-7) engages multiple mechanisms to overcome chronic viral infections, but the role of IL-7 in bacterial infections, especially enteric bacterial infections, remains unclear. Here we characterized the previously unexplored role of IL-7 in the innate immune response to the attaching and effacing bacteriumCitrobacter rodentium.C. rodentiuminfection induced IL-7 production from intestinal epithelial cells (IECs). IL-7 production from IECs in response toC. rodentiumwas dependent on gamma interferon (IFN-γ)-producing NK1.1+cells and IL-12. Treatment with anti-IL-7Rα antibody duringC. rodentiuminfection resulted in a higher bacterial burden, enhanced intestinal damage, and greater weight loss and mortality than observed with the control IgG treatment. IEC-produced IL-7 was only essential for protective immunity againstC. rodentiumduring the first 6 days after infection. An impaired bacterial clearance upon IL-7Rα blockade was associated with a significant decrease in macrophage accumulation and activation in the colon. Moreover,C. rodentium-induced expansion and activation of intestinal CD4+lymphoid tissue inducer (LTi) cells was completely abrogated by IL-7Rα blockade. Collectively, these data demonstrate that IL-7 is produced by IECs in response toC. rodentiuminfection and plays a critical role in the protective immunity against this intestinal attaching and effacing bacterium.

scholarly journals CapC, a Novel Autotransporter and Virulence Factor ofCampylobacter jejuni

2018 ◽  
Vol 84 (16) ◽  
Author(s):  
Jai W. Mehat ◽  
Simon F. Park ◽  
Arnoud H. M. van Vliet ◽  
Roberto M. La Ragione
Keyword(s):  
Public Health ◽  
Epithelial Cells ◽  
Campylobacter Jejuni ◽  
Virulence Factor ◽  
Causative Agent ◽  
Galleria Mellonella ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Content Type ◽  
Reduced Adherence

ABSTRACTCampylobacter jejuniis recognized as an important causative agent of bacterial gastroenteritis in the developed world. Despite the identification of several factors contributing to infection, characterization of the virulence strategies employed byC. jejuniremains a significant challenge. Bacterial autotransporter proteins are a major class of secretory proteins in Gram-negative bacteria, and notably, many autotransporter proteins contribute to bacterial virulence. The aim of this study was to characterize theC. jejuni81116 C8J_1278 gene (capC), predicted to encode an autotransporter protein, and examine the contribution of this factor to virulence ofC. jejuni. The predicted CapC protein has a number of features that are consistent with autotransporters, including the N-terminal signal sequence and the C-terminal β-barrel domain and was determined to localize to the outer membrane. Inactivation of thecapCgene inC. jejuni81116 andC. jejuniM1 resulted in reduced insecticidal activity inGalleria mellonellalarvae. Furthermore,C. jejuni capCmutants displayed significantly reduced adherence to and invasion of nonpolarized, partially differentiated Caco-2 and T84 intestinal epithelial cells. Gentamicin treatment showed that the reduced invasion of thecapCmutant is primarily caused by reduced adherence to intestinal epithelial cells, not by reduced invasion capability.C. jejuni capCmutants caused reduced interleukin 8 (IL-8) secretion from intestinal epithelial cells and elicited a significantly diminished immune reaction inGallerialarvae, indicating that CapC functions as an immunogen. In conclusion, CapC is a new virulence determinant ofC. jejunithat contributes to the integral infection process of adhesion to human intestinal epithelial cells.IMPORTANCECampylobacter jejuniis a major causative agent of human gastroenteritis, making this zoonotic pathogen of significant importance to human and veterinary public health worldwide. The mechanisms by whichC. jejuniinteracts with intestinal epithelial cells and causes disease are still poorly understood due, in part, to the heterogeneity ofC. jejuniinfection biology. Given the importance ofC. jejunito public health, the need to characterize novel and existing virulence mechanisms is apparent. The significance of our research is in demonstrating the role of CapC, a novel virulence factor inC. jejunithat contributes to adhesion and invasion of the intestinal epithelium, thereby in part, addressing the dearth of knowledge concerning the factors involved inCampylobacterpathogenesis and the variation observed in the severity of human infection.

scholarly journals O-Antigen Delays Lipopolysaccharide Recognition and Impairs Antibacterial Host Defense in Murine Intestinal Epithelial Cells

2009 ◽  
Vol 5 (9) ◽  
pp. e1000567 ◽  
Author(s):  
Claudia U. Duerr ◽  
Sebastian F. Zenk ◽  
Cécilia Chassin ◽  
Johanna Pott ◽  
Dominique Gütle ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Host Defense ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
O Antigen ◽  
Antibacterial Host Defense

scholarly journals In VitroPrevention ofSalmonellaLipopolysaccharide-Induced Damages in Epithelial Barrier Function by VariousLactobacillusStrains

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Chun-Yan Yeung ◽  
Jen-Shiu Chiang Chiau ◽  
Wai-Tao Chan ◽  
Chun-Bin Jiang ◽  
Mei-Lien Cheng ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Mononuclear Cells ◽  
Intestinal Epithelial Cells ◽  
Barrier Properties ◽  
Bacterial Invasion ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Peripheral Blood Mononuclear

Background.Lactobacillusshows beneficial anti-inflammatory effects onSalmonellainfection. The maintenance of the tight junction (TJ) integrity plays an importance role in avoiding bacterial invasion. WhetherLactobacilluscould be used to regulate the TJ protein expression and distribution in inflamed intestinal epithelial cells was determined.Methods. Using the transwell coculture model,Salmonellalipopolysaccharide (LPS) was apically added to polarized Caco-2 cells cocultured with peripheral blood mononuclear cells in the basolateral compartment. LPS-stimulated Caco-2 cells were incubated with variousLactobacillusstrains. TJ integrity was determined by measuring transepithelial electrical resistance across Caco-2 monolayer. Expression and localization of TJ proteins (zonula-occludens- (ZO-) 1) were determined by Western blot and immunofluorescence microscopy.Results. Various strains ofLactobacilluswere responsible for the different modulations of cell layer integrity. LPS was specifically able to disrupt epithelial barrier and change the location of ZO-1. Our data demonstrate thatLactobacilluscould attenuate the barrier disruption of intestinal epithelial cells caused bySalmonellaLPS administration. We showed thatLactobacillusstrains are associated with the maintenance of the tight junction integrity and appearance.Conclusion. In this study we provide insight that live probiotics could improve epithelial barrier properties and this may explain the potential mechanism behind their beneficial effectin vivo.

Enteric glia protect against Shigella flexneri invasion in intestinal epithelial cells: a role for S-nitrosoglutathione

Gut ◽  
2010 ◽  
Vol 60 (4) ◽  
pp. 473-484 ◽  
Author(s):  
M. Flamant ◽  
P. Aubert ◽  
M. Rolli-Derkinderen ◽  
A. Bourreille ◽  
M. R. Neunlist ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Shigella Flexneri ◽  
Intestinal Epithelial ◽  
Enteric Glia

Reovirus type 1 and type 3 differ in their binding to isolated intestinal epithelial cells

1988 ◽  
Vol 5 (1) ◽  
pp. 29-40 ◽  
Author(s):  
David B. Weiner ◽  
Karen Girard ◽  
William V. Williams ◽  
Thomas McPhillips ◽  
Donald H. Rubin
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Reovirus Type ◽  
Type 3

scholarly journals Inhibition of the NF-κB Pathway in Human Intestinal Epithelial Cells by Commensal Streptococcus salivarius

2011 ◽  
Vol 77 (13) ◽  
pp. 4681-4684 ◽  
Author(s):  
Ghalia Kaci ◽  
Omar Lakhdari ◽  
Joël Doré ◽  
S. Dusko Ehrlich ◽  
Pierre Renault ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Streptococcus Salivarius ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Human Intestinal Epithelial Cells ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACTStreptococcus salivariusexhibited an anti-inflammatory effect on intestinal epithelial cells (IECs) and monocytes. Strains were screened using a reporter clone, HT-29/kB-luc-E, induced by tumor necrosis factor alpha (TNF-α). Supernatant from each strain downregulated NF-κB activation. The two most efficient strains produced an active metabolite (<3 kDa) which was able to downregulate the secretion of the proinflammatory chemokine interleukin-8 (IL-8).

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