The Proinflammatory Response Induced by Wild-Type Yersinia pseudotuberculosis Infection Inhibits Survival of yop Mutants in the Gastrointestinal Tract and Peyer's Patches

ABSTRACT Single-strain infections and coinfections are frequently used to assess roles of virulence factors in infected tissues. After oral inoculation of mice, Yersinia pseudotuberculosis yopE and yopH mutants colonize the intestines and Peyer's patches in single-strain infections but fail to persist in competition with wild-type Y. pseudotuberculosis, indicating that these two infection models provide different insights into the roles of Yops. To determine how wild-type Y. pseudotuberculosis hinders yop mutant survival, yop mutant colonization and host responses were investigated in several different infection models that isolated specific features of wild-type Y. pseudotuberculosis infection. Infection with wild-type Y. pseudotuberculosis caused significantly more inflammation than yop mutants. Results from coinfections of gamma interferon (IFN-γ)−/− mice revealed that IFN-γ-regulated defenses target these mutants, suggesting that YopE and YopH protect Y. pseudotuberculosis from these defenses in BALB/c mice. We developed an oral-intraperitoneal infection model to evaluate the effects of spleen and liver colonization by Y. pseudotuberculosis on yop mutants in the intestines. Spleen and liver infection increased inflammation and decreased yop mutant survival in the intestines, indicating that infection of these organs has consequences in intestinal tissues. Finally, competition infections with Y. pseudotuberculosis mutants with various abilities to induce inflammation demonstrated that survival of the yopE, but not the yopH, mutant was consistently decreased in inflamed tissues. In summary, infection with Y. pseudotuberculosis in intestinal and systemic sites induces intestinal inflammation, which decreases yop mutant survival. Thus, competition studies with wild-type yersiniae reveal critical roles of Yops in combating host responses to a normal virulent infection.

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Salmonella Exploits Caspase-1 to Colonize Peyer's Patches in a Murine Typhoid Model

Journal of Experimental Medicine ◽

10.1084/jem.192.2.249 ◽

2000 ◽

Vol 192 (2) ◽

pp. 249-258 ◽

Cited By ~ 162

Author(s):

Denise M. Monack ◽

David Hersh ◽

Nafisa Ghori ◽

Donna Bouley ◽

Arturo Zychlinsky ◽

...

Keyword(s):

Proinflammatory Cytokines ◽

Mammalian Cells ◽

Yersinia Pseudotuberculosis ◽

Lethal Dose ◽

Cysteine Proteases ◽

Peyer's Patches ◽

Peyer’S Patches ◽

Wild Type ◽

M Cell ◽

Caspase 1

Salmonella typhimurium invades host macrophages and induces apoptosis and the release of mature proinflammatory cytokines. SipB, a protein translocated by Salmonella into the cytoplasm of macrophages, is required for activation of Caspase-1 (Casp-1, an interleukin [IL]-1β–converting enzyme), which is a member of a family of cysteine proteases that induce apoptosis in mammalian cells. Casp-1 is unique among caspases because it also directly cleaves the proinflammatory cytokines IL-1β and IL-18 to produce bioactive cytokines. We show here that mice lacking Casp-1 (casp-1−/− mice) had an oral S. typhimurium 50% lethal dose (LD50) that was 1,000-fold higher than that of wild-type mice. Salmonella breached the M cell barrier of casp-1−/− mice efficiently; however, there was a decrease in the number of apoptotic cells, intracellular bacteria, and the recruitment of polymorphonuclear lymphocytes in the Peyer's patches (PP) as compared with wild-type mice. Furthermore, Salmonella did not disseminate systemically in the majority of casp-1−/− mice, as demonstrated by significantly less colonization in the PP, mesenteric lymph nodes, and spleens of casp-1−/− mice after an oral dose of S. typhimurium that was 100-fold higher than the LD50. The increased resistance in casp-1−/− animals appears specific for Salmonella infection since these mice were susceptible to colonization by another enteric pathogen, Yersinia pseudotuberculosis, which normally invades the PP. These results show that Casp-1, which is both proapoptotic and proinflammatory, is essential for S. typhimurium to efficiently colonize the cecum and PP and subsequently cause systemic typhoid-like disease in mice.

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Requirement of the Yersinia pseudotuberculosis Effectors YopH and YopE in Colonization and Persistence in Intestinal and Lymph Tissues

Infection and Immunity ◽

10.1128/iai.71.8.4595-4607.2003 ◽

2003 ◽

Vol 71 (8) ◽

pp. 4595-4607 ◽

Cited By ~ 89

Author(s):

Lauren K. Logsdon ◽

Joan Mecsas

Keyword(s):

Mutant Strain ◽

Type Iii Secretion ◽

Yersinia Pseudotuberculosis ◽

Host Responses ◽

Wild Type ◽

Mesenteric Lymph Nodes ◽

Single Strain ◽

Type Iii ◽

Mutant Strains ◽

Redundant Functions

ABSTRACT The gram-negative enteric pathogen Yersinia pseudotuberculosis employs a type III secretion system and effector Yop proteins that are required for virulence. Mutations in the type III secretion-translocation apparatus have been shown to cause defects in colonization of the murine cecum, suggesting roles for one or more effector Yops in the intestinal tract. To investigate this possibility, isogenic yop mutant strains were tested for their ability to colonize and persist in intestinal and associated lymph tissues of the mouse following orogastric inoculation. In single-strain infections, a yopHEMOJ mutant strain was unable to colonize, replicate, or persist in intestinal and lymph tissues. A yopH mutant strain specifically fails to colonize the mesenteric lymph nodes, but yopE and yopO mutant strains showed only minor defects in persistence in intestinal and lymph tissues. While no single Yop was found to be essential for colonization or persistence in intestinal tissues in single-strain infections, the absence of both YopH and YopE together almost eliminated colonization of all tissues, indicating either that these two Yops have some redundant functions or that Y. pseudotuberculosis employs multiple strategies for colonization. In competition infections with wild-type Y. pseudotuberculosis, the presence of wild-type bacteria severely hindered the ability of the yopH, yopE, and yopO mutants to persist in many tissues, suggesting that the wild-type bacteria either fills colonization niches or elicits host responses that the yop mutants are unable to withstand.

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Superantigen YPMa Exacerbates the Virulence ofYersinia pseudotuberculosis in Mice

Infection and Immunity ◽

10.1128/iai.68.5.2553-2559.2000 ◽

2000 ◽

Vol 68 (5) ◽

pp. 2553-2559 ◽

Cited By ~ 31

Author(s):

Christophe Carnoy ◽

Chantal Mullet ◽

Heide Müller-Alouf ◽

Emmanuelle Leteurtre ◽

Michel Simonet

Keyword(s):

Yersinia Pseudotuberculosis ◽

Systemic Infection ◽

Peyer's Patches ◽

Peyer’S Patches ◽

Wild Type ◽

Bacterial Inoculation ◽

Mesenteric Lymph Nodes ◽

Strain Determination ◽

Mouse Model Of Infection

ABSTRACT Yersinia pseudotuberculosis, a gram-negative bacterium responsible for enteric and systemic infection in humans, produces a superantigenic toxin designated YPMa (Y. pseudotuberculosis-derived mitogen). To assess the role of YPMa in the pathogenesis of Y. pseudotuberculosis, we constructed a superantigen-deficient mutant and compared its virulence in a mouse model of infection to the virulence of the wild-type strain. Determination of the survival rate after intravenous (i.v.) bacterial inoculation of OF1 mice clearly showed that inactivation ofypmA, encoding YPMa, reduced the virulence of Y. pseudotuberculosis. Mice infected i.v. with 104 and 105 wild-type bacteria died within 9 days, whereas mice infected with the ypmA mutant survived 12 and 3 days longer, respectively. This decreased virulence of the ypmAmutant strain was not due to an impaired colonization of the spleen, liver, or lungs. In contrast to i.v. challenge, bacterial inoculation by the intragastric (i.g.) route did not reveal any difference in virulence between wild-type Y. pseudotuberculosis and theypmA mutant since the 50% lethal doses were identical for both strains. Moreover, inactivation of ypmA gene did not affect the bacterial growth of Y. pseudotuberculosis in Peyer's patches, mesenteric lymph nodes (MLNs), and spleen after oral infection. Histological studies of spleen, liver, lungs, heart, Peyer's patches, and MLNs after i.v. or i.g. challenge with the wild type or the ypmA mutant did not reveal any feature that can be specifically related to YPMa. Our data show that the superantigenic toxin YPMa contributes to the virulence of Y. pseudotuberculosis in systemic infection in mice.

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Type III Secretion Decreases Bacterial and Host Survival following Phagocytosis of Yersinia pseudotuberculosis by Macrophages

Infection and Immunity ◽

10.1128/iai.00183-08 ◽

2008 ◽

Vol 76 (9) ◽

pp. 4299-4310 ◽

Cited By ~ 24

Author(s):

Yue Zhang ◽

James Murtha ◽

Margaret A. Roberts ◽

Richard M. Siegel ◽

James B. Bliska

Keyword(s):

Cell Death ◽

Type Iii Secretion ◽

Yersinia Pseudotuberculosis ◽

De Novo ◽

Host Cells ◽

Host Responses ◽

Intracellular Bacteria ◽

Wild Type ◽

Macrophage Response ◽

Type Iii

ABSTRACT Yersinia pseudotuberculosis uses a plasmid (pYV)-encoded type III secretion system (T3SS) to translocate a set of effectors called Yops into infected host cells. YopJ functions to induce apoptosis, and YopT, YopE, and YopH act to antagonize phagocytosis in macrophages. Because Yops do not completely block phagocytosis and Y. pseudotuberculosis can replicate in macrophages, it is important to determine if the T3SS modulates host responses to intracellular bacteria. Isogenic pYV-cured, pYV+ wild-type, and yop mutant Y. pseudotuberculosis strains were allowed to infect bone marrow-derived murine macrophages at a low multiplicity of infection under conditions in which the survival of extracellular bacteria was prevented. Phagocytosis, the intracellular survival of the bacteria, and the apoptosis of the infected macrophages were analyzed. Forty percent of cell-associated wild-type bacteria were intracellular after a 20-min infection, allowing the study of the macrophage response to internalized pYV+ Y. pseudotuberculosis. Interestingly, macrophages restricted survival of pYV+ but not pYV-cured or ΔyopB Y. pseudotuberculosis within phagosomes: only a small fraction of the pYV+ bacteria internalized replicated by 24 h. In addition, ∼20% of macrophages infected with wild-type pYV+ Y. pseudotuberculosis died of apoptosis after 20 h. Analysis of yop mutants expressing catalytically inactive effectors revealed that YopJ was important for apoptosis, while a role for YopE, YopH, and YopT in modulating macrophage responses to intracellular bacteria could not be identified. Apoptosis was reduced in Toll-like receptor 4-deficient macrophages, indicating that cell death required signaling through this receptor. Treatment of macrophages harboring intracellular pYV+ Y. pseudotuberculosis with chloramphenicol reduced apoptosis, indicating that the de novo bacterial protein synthesis was necessary for cell death. Our finding that the presence of a functional T3SS impacts the survival of both bacterium and host following phagocytosis of Y. pseudotuberculosis suggests new roles for the T3SS in Yersinia pathogenesis.

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Decreased Apoptosis in the Ileum and Ileal Peyer's Patches: a Feature after Infection with Rabbit EnteropathogenicEscherichia coli O103

Infection and Immunity ◽

10.1128/iai.69.7.4580-4589.2001 ◽

2001 ◽

Vol 69 (7) ◽

pp. 4580-4589 ◽

Cited By ~ 29

Author(s):

Ursula Heczko ◽

Chris M. Carthy ◽

Bronwyn A. O'Brien ◽

B. Brett Finlay

Keyword(s):

Caspase 3 ◽

Cultured Cells ◽

Apoptotic Cell ◽

Light And Electron Microscopy ◽

Germinal Centers ◽

Peyer's Patches ◽

Infection Model ◽

Peyer’S Patches ◽

Rabbit Ileum ◽

Cell Counts

ABSTRACT Significant changes occur in intestinal epithelial cells after infection with enteropathogenic Escherichia coli (EPEC). However, it is unclear whether this pathogen alters rates of apoptosis. By using a naturally occurring weaned rabbit infection model, we determined physiological levels of apoptosis in rabbit ileum and ileal Peyer's patches (PP) and compared them to those found after infection with adherent rabbit EPEC (REPEC O103). Various REPEC O103 strains were first tested in vitro for characteristic virulence features. Rabbits were then inoculated with the REPEC O103 strains that infected cultured cells the most efficiently. After experimental infection, intestinal samples were examined by light and electron microscopy. Simultaneously, ileal apoptosis was assessed by using terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) and caspase 3 assays and by apoptotic cell counts based on morphology (hematoxylin-and-eosin staining). The highest physiological apoptotic indices were measured in PP germinal centers (median = 14.7%), followed by PP domed villi (8.1%), tips of absorptive villi (3.8%), and ileal crypt regions (0.5%). Severe infection with REPEC O103 resulted in a significant decrease in apoptosis in PP germinal centers (determined by TUNEL assay; P = 0.01), in the tips of ileal absorptive villi (determined by H&E staining;P = 0.04), and in whole ileal cell lysates (determined by caspase 3 assay; P = 0.001). We concluded that REPEC O103 does not promote apoptosis. Furthermore, we cannot rule out the possibility that REPEC O103, in fact, decreases apoptotic levels in the rabbit ileum.

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The rovA Mutant of Yersinia enterocolitica Displays Differential Degrees of Virulence Depending on the Route of Infection

Infection and Immunity ◽

10.1128/iai.71.6.3512-3520.2003 ◽

2003 ◽

Vol 71 (6) ◽

pp. 3512-3520 ◽

Cited By ~ 33

Author(s):

Peter H. Dube ◽

Scott A. Handley ◽

Paula A. Revell ◽

Virginia L. Miller

Keyword(s):

Yersinia Enterocolitica ◽

Inflammatory Disease ◽

Inflammatory Responses ◽

Systemic Disease ◽

Lethal Dose ◽

Peyer's Patches ◽

Peyer’S Patches ◽

Wild Type ◽

Global Regulator ◽

Kinetics Of

ABSTRACT Yersinia enterocolitica is an invasive enteric pathogen that causes significant inflammatory disease. Recently, we identified and characterized a global regulator of virulence (rovA). When mice are infected orally with the rovA mutant they are attenuated by 50% lethal dose (LD50) analysis and have altered kinetics of infection. Most significantly, mice orally infected with the rovA mutant have greatly reduced inflammation in the Peyer's patches compared to those infected with wild-type Y. enterocolitica. However, we present data here indicating that when the rovA mutant bacteria are delivered intraperitoneally (i.p.), they are significantly more virulent than when delivered orally. The i.p. LD50 for the rovA mutant is only 10-fold higher than that of the wild-type Y. enterocolitica, and there are significant inflammatory responses to the rovA mutant that are evident in the liver and spleen. Altogether, these data suggest that the RovA regulon may be required for the early events of the infection that occur in the Peyer's patches. Furthermore, these data suggest that the RovA regulon may be dispensable for Y. enterocolitica systemic disease and inflammatory responses if the Peyer's patches are bypassed.

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In Vivo-Induced InvA-Like Autotransporters Ifp and InvC of Yersinia pseudotuberculosis Promote Interactions with Intestinal Epithelial Cells and Contribute to Virulence

Infection and Immunity ◽

10.1128/iai.05715-11 ◽

2011 ◽

Vol 80 (3) ◽

pp. 1050-1064 ◽

Cited By ~ 19

Author(s):

Fabio Pisano ◽

Annika Kochut ◽

Frank Uliczka ◽

Rebecca Geyer ◽

Tatjana Stolz ◽

...

Keyword(s):

Epithelial Cells ◽

Yersinia Pseudotuberculosis ◽

Intestinal Epithelial Cells ◽

Bacterial Colonization ◽

Immune Defense ◽

Peyer's Patches ◽

Peyer’S Patches ◽

Intestinal Epithelial ◽

Content Type ◽

K 12

TheYersinia pseudotuberculosisIfp and InvC molecules are putative autotransporter proteins with a high homology to the invasin (InvA) protein. To characterize the function of these surface proteins, we expressed both factors inEscherichia coliK-12 and demonstrated the attachment of Ifp- and InvC-expressing bacteria to human-, mouse-, and pig-derived intestinal epithelial cells. Ifp also was found to mediate microcolony formation and internalization into polarized human enterocytes. TheifpandinvCgenes were not expressed underin vitroconditions but were found to be induced in the Peyer's patches of the mouse intestinal tract. In a murine coinfection model, the colonization of the Peyer's patches and the mesenteric lymph nodes of mice by theifp-deficient strain was significantly reduced, and considerably fewer bacteria reached liver and spleen. The absence of InvC did not have a severe influence on bacterial colonization in the murine infection model, and it resulted in only a slightly reduced number ofinvCmutants in the Peyer's patches. The analysis of the host immune response demonstrated that the presence of Ifp and InvC reduced the recruitment of professional phagocytes, especially neutrophils, in the Peyer's patches. These findings support a role for the adhesins in modulating host-pathogen interactions that are important for immune defense.

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Chemokine Requirements for B Cell Entry to Lymph Nodes and Peyer's Patches

Journal of Experimental Medicine ◽

10.1084/jem.20020201 ◽

2002 ◽

Vol 196 (1) ◽

pp. 65-75 ◽

Cited By ~ 352

Author(s):

Takaharu Okada ◽

Vu N. Ngo ◽

Eric H. Ekland ◽

Reinhold Förster ◽

Martin Lipp ◽

...

Keyword(s):

Lymph Nodes ◽

B Cell ◽

Chemokine Receptor ◽

Cell Entry ◽

Peyer's Patches ◽

Peyer’S Patches ◽

Wild Type ◽

High Endothelial Venules ◽

Cell Homing ◽

T Cell Homing

B cell entry to lymph nodes and Peyer's patches depends on chemokine receptor signaling, but the principal chemokine involved has not been defined. Here we show that the homing of CXCR4−/− B cells is suppressed in CCL19 (ELC)- and CCL21 (SLC)-deficient paucity of lymph node T cells mice, but not in wild-type mice. We also find that CXCR4 can contribute to T cell homing. Using intravital microscopy, we find that B cell adhesion to high endothelial venules (HEVs) is disrupted when CCR7 and CXCR4 are predesensitized. In Peyer's patches, B cell entry is dependent on CXCR5 in addition to CCR7/CXCR4. CXCL12 (SDF1) is displayed broadly on HEVs, whereas CXCL13 (BLC) is found selectively on Peyer's patch follicular HEVs. These findings establish the principal chemokine and chemokine receptor requirements for B cell entry to lymph nodes and Peyer's patches.

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Efficacy of Humanized Carbapenem and Ceftazidime Regimens against Enterobacteriaceae Producing OXA-48 Carbapenemase in a Murine Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01947-13 ◽

2013 ◽

Vol 58 (3) ◽

pp. 1678-1683 ◽

Cited By ~ 29

Author(s):

Dora E. Wiskirchen ◽

Patrice Nordmann ◽

Jared L. Crandon ◽

David P. Nicolau

Keyword(s):

Wild Type Strain ◽

Treatment Options ◽

Infection Model ◽

Wild Type ◽

Content Type ◽

Phenotypic Profile ◽

Infection Models ◽

The Relationship ◽

Growth Controls

ABSTRACTEnterobacteriaceaeproducing the OXA-48 carbapenemase are emerging worldwide, leaving few treatment options. Efficacy has been demonstratedin vivowith ceftazidime against a ceftazidime-susceptible OXA-48 isolate but not with imipenem despite maintaining susceptibility. The relationship between phenotype andin vivoefficacy was assessed for OXA-48 producers using humanized regimens of 2 g doripenem every 8 h (q8h; 4 h infusion), 1 g ertapenem q24h, 2 g ceftazidime q8h (2 h inf), and 500 mg levofloxacin q24h. Each regimen was evaluated over 24 h against an isogenic pair (wild-type and OXA-48Klebsiella pneumoniaestrains) and six clinical OXA-48 isolates with and without other extended-spectrum β-lactamases in immunocompetent and neutropenic murine thigh infection models. Efficacy was determined using the change in bacterial density versus 24-h growth controls in immunocompetent studies and 0-h controls in neutropenic studies. Bacterial reductions of ≥1 log CFU were observed with all agents for the wild-type strain. Consistent with low MICs, ceftazidime and levofloxacin exhibited efficacy against the isogenic OXA-48 strain, whereas doripenem did not, despite having a susceptible MIC; no activity was observed with ertapenem, consistent with a resistant MIC. Similar trends were observed for the clinical isolates evaluated. Ceftazidime, levofloxacin, and ertapenem efficacy against isogenic and clinical OXA-48-producing strains correlated well with phenotypic profiles and pharmacodynamic targets, whereas efficacy with doripenem was variable over the MIC range studied. These data suggest that carbapenems may not be a reliable treatment for treating OXA-48 producers and add to previous observations with KPC and NDM-1 suggesting that genotype may better predict activity of the carbapenems than the phenotypic profile.

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Oral Norovirus Infection Is Blocked in Mice Lacking Peyer's Patches and Mature M Cells

Journal of Virology ◽

10.1128/jvi.02872-15 ◽

2015 ◽

Vol 90 (3) ◽

pp. 1499-1506 ◽

Cited By ~ 19

Author(s):

Abimbola O. Kolawole ◽

Mariam B. Gonzalez-Hernandez ◽

Holly Turula ◽

Chenchen Yu ◽

Michael D. Elftman ◽

...

Keyword(s):

Dendritic Cells ◽

Peyer's Patches ◽

Epithelial Barrier ◽

Target Cells ◽

Lymphoid Tissues ◽

Peyer’S Patches ◽

M Cells ◽

Intestinal Epithelial ◽

Wild Type ◽

Intestinal Epithelial Barrier

ABSTRACTA critical early step in murine norovirus (MNV) pathogenesis is crossing the intestinal epithelial barrier to reach the target cells for replication, i.e., macrophages, dendritic cells, and B cells. Our previous work showed that MNV replication decreases in the intestines of mice conditionally depleted of microfold (M) cells. To define the importance of Peyer's patch (PP) M cells during MNV pathogenesis, we used a model of BALB/c mice deficient in recombination-activating gene 2 (Rag2) and the common gamma chain (γc) (Rag-γc−/−), which lack gut-associated lymphoid tissues (GALT), such as Peyer's patches, and mature GP2+M cells. Rag-γc−/−mice were infected intraperitoneally or perorally with MNV-1 or CR3 for 24 or 72 h. Although the intestinal laminae propriae of Rag-γc−/−mice have a higher frequency of certain MNV target cells (dendritic cells and macrophages) than those of wild-type mice and lack others (B cells), Rag-γc−/−and wild-type BALB/c mice showed relatively similar viral loads in the intestine following infection by the intraperitoneal route, which provides direct access to target cells. However, Rag-γc−/−mice were not productively infected with MNV by the oral route, in which virions must cross the intestinal epithelial barrier. These data are consistent with a model whereby PP M cells are the primary route by which MNV crosses the intestinal epithelia of BALB/c mice.IMPORTANCENoroviruses (NoVs) are prevalent pathogens that infect their hosts via the intestine. Identifying key factors during the initial stages of virus infection in the host may provide novel points of intervention. Microfold (M) cells, antigen-sampling cells in the intestine, were previously shown to provide a gateway for murine NoV (MNV) into the host, but the relative importance of this uptake pathway remained unknown. Here we show that the absence of gut-associated lymphoid tissues (GALT), such as Peyer's patches, which contain high numbers of mature M cells, renders BALB/c mice refractory to oral infection with MNV. These findings are consistent with the model that M cells represent the primary route by which MNV crosses the intestinal epithelial barrier and infects underlying immune cells during a productive infection.

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