Seroepidemiological survey of pathogenic Yersinia in domestic pigs in Chiba Prefecture, Japan

This study aimed to investigate the prevalence of antibodies against pathogenic Yersinia such as Y. enterocolitica and Y. pseudotuberculosis in domestic pigs. A total of 650 serum samples from pigs in nine regions of the Chiba Prefecture in Japan, were tested using plasmid-encoded Yersinia outer membrane protein (Yops) antigen ELISA. The cutoff value was calculated using 20 pathogenic Yersinia-free pig serum samples. According to the cutoff value, 246 (37.8%) pigs from seven regions were considered seropositive for pathogenic Yersinia during the study period. These results indicate that pathogenic Yersinia is widespread in pigs in Chiba, which may become the source of human yersiniosis in this region.

A TNF-IL-1 circuit controls Yersinia within intestinal pyogranulomas

Tumor necrosis factor (TNF) is a pleiotropic inflammatory cytokine that mediates antimicrobial defense and granuloma formation in response to infection by numerous pathogens. We previously reported that Yersinia pseudotuberculosis colonizes the intestinal mucosa and induces the recruitment of neutrophils and inflammatory monocytes into organized immune structures termed pyogranulomas (PG) that control Yersinia infection. Inflammatory monocytes are essential for the control and clearance of Yersinia within intestinal PG, but how monocytes mediate Yersinia restriction is poorly understood. Here, we demonstrate that TNF signaling in monocytes is required for bacterial containment following enteric Yersinia infection. We further show that monocyte-intrinsic TNFR1 signaling drives the production of monocyte-derived interleukin-1 (IL-1), which signals through IL-1 receptors on non-hematopoietic cells to enable PG-mediated control of intestinal Yersinia infection. Altogether, our work reveals a monocyte-intrinsic TNF-IL-1 collaborative inflammatory circuit that restricts intestinal Yersinia infection.

Yersinia pseudotuberculosis in an alpaca

A 6-year-old female huacaya alpaca was referred to the clinic for evaluation with a 1-month history of rapid weight loss, inappetence, lethargy, and severe leukocytosis refractory to medical management. Physical examination revealed a body condition score of 1 out of 5 and a large, firm structure palpable in the right caudoventral abdomen. Abdominal ultrasonographic examination revealed 3 masses with hyperechoic, swirling centers. The largest mass measured 15 cm in diameter with a 2-centimeter capsule, and extended from right of midline into the left inguinal region. Transrectal ultrasonography identified a small uterus and clear delineation between the abdominal masses. Complete blood (cell) count findings were consistent with marked systemic inflammation. Based on initial examination and laboratory findings, exploratory laparotomy was elected. Multiple mesenteric masses strongly adhered to the jejunum were observed within the abdomen. Due to the inoperable conditions and the poor long-term prognosis, the alpaca was euthanized under general anesthesia. Bacterial culture of fluid aspirated from the largest mass revealed Yersinia pseudotuberculosis. Key clinical message: Clinical progression and attempted treatment of Yersinia pseudotuberculosis in camelids have not been previously described and the bacterium should be considered as a differential diagnosis for abscessation and persistent leukocytosis. Yersinia pseudotuberculosis is also considered a zoonotic agent and proper precautions should be taken when handling cases of abdominal abscessation.

Association of Yersinia Infection With Kawasaki Disease: A Prospective Multicenter Cohort Study

BACKGROUND

Yersinia infection is known to present with Kawasaki disease (KD)-like symptoms although differentiating the 2 has been a challenge. The present study aimed to describe the clinical characteristics and prevalence of Yersinia infection presenting with KD-like symptoms.

METHODS

The present, prospective, multicenter study enrolled patients who received a diagnosis of KD between January 2021 and January 2022 at 2 hospitals in Tokyo. Stool samples were collected within 3 days of the start of KD treatment, and cultures were performed for Yersinia . Clinical history and symptoms suggestive of Yersinia infection were also evaluated.

RESULTS

During the study period, 141 KD patients were screened and 117 patients with evaluable stool samples were registered. Only 1 patient was positive for Yersinia pseudotuberculosis , which was detected from both stool and blood cultures. The patient was refractory to KD treatment but improved after initiation of appropriate antibiotic therapy.

CONCLUSIONS

Routine screening for Yersinia is not appropriate for patients with KD and should be limited to certain patients in high-risk areas and those who are refractory to the standard KD treatment.

Yersinia deploys type III-secreted effectors to evade caspase-4 inflammasome activation in human cells

IMPORTANCE

Yersinia are responsible for significant disease burden in humans, ranging from recurrent disease outbreaks (yersiniosis) to pandemics (Yersinia pestis plague). Together with rising antibiotic resistance rates, there is a critical need to better understand Yersinia pathogenesis and host immune mechanisms, as this information will aid in developing improved immunomodulatory therapeutics. Inflammasome responses in human cells are less studied relative to murine models of infection, though recent studies have uncovered key differences in inflammasome responses between mice and humans. Here, we dissect human intestinal epithelial cell and macrophage inflammasome responses to Yersinia pseudotuberculosis. Our findings provide insight into species- and cell type-specific differences in inflammasome responses to Yersinia.

[Far East scarlet-like fever in a Caucasian man with Yersinia pseudotuberculosis bacteriaemia]

Yersinia pseudotuberculosis is a Gram-negative bacterium causing infection in humans through contaminated water and/or food. The infection commonly occurs as gastroenteritis and fever, abdominal pain due to mesenteric lymphadenitis and diarrhoea. Bacteraemia is rare and is typically seen in immunocompromised patients and occurs with different clinical presentations like Far East scarlet-like fever, splenic abscess, or mimic appendicitis. This is a case report of Y. pseudotuberculosis bacteraemia and splenic abscess in a Caucasian male.

[Pseudotuberculosis - a case report of gastroenteritis in a five-year-old boy]

The article describes a case of a rare infection caused by Yersinia pseudotuberculosis in a five-year-old boy admitted to the hospital. The infection was manifested by the so-called right lower quadrant syndrome, or terminal ileitis. The Y. pseudotuberculosis strain was isolated from the patient's feces and its biochemical properties are reported. Confirmation was performed by the National Reference Laboratory for E. coli and Shigella. Since pseudotuberculosis is very rare in the Czech Republic, the authors would like to draw attention to this infection. Enlargement of lymph nodes in the right lower quadrant of the abdomen may suggest the infection caused by Y. pseudotuberculosis.

Effective discrimination of Yersinia pestis and Yersinia pseudotuberculosis by MALDI-TOF MS using multivariate analysis

Separating Yersinia pseudotuberculosis and Yersinia pestis is an important issue in plague diagnosis but can be extremely difficult because of the high similarity between the two species. MALDI-TOF MS has grown as a diagnostic tool with great potential in bacterial identification. Its application in this field is largely enhanced by multivariate analysis, especially in extracting subtle spectral differences. In this study, we built a complete MALDI-TOF MS data pipeline and found a Y. pestis-specific biomarker at 3063 Da closely related to Y. pestis plasminogen activation factor. Based on this, we achieved almost perfect separation between Y. pseudotuberculosis and Y. pestis (AUC = 0.999) using a supervised linear discriminant analysis (LDA) model. This is significantly better than the conventionally applied unsupervised spectral similarity comparison methods, such as hierarchical clustering analysis (HCA), which gave a separation accuracy of 75.0%. This new computing method paves the way for automatic differentiation between the two highly similar bacterial species with high separation accuracy.

Molecular and Genetic Mechanisms That Mediate Transmission of Yersinia pestis by Fleas

The ability to cause plague in mammals represents only half of the life history of Yersinia pestis. It is also able to colonize and produce a transmissible infection in the digestive tract of the flea, its insect host. Parallel to studies of the molecular mechanisms by which Y. pestis is able to overcome the immune response of its mammalian hosts, disseminate, and produce septicemia, studies of Y. pestis-flea interactions have led to the identification and characterization of important factors that lead to transmission by flea bite. Y. pestis adapts to the unique conditions in the flea gut by altering its metabolic physiology in ways that promote biofilm development, a common strategy by which bacteria cope with a nutrient-limited environment. Biofilm localization to the flea foregut disrupts normal fluid dynamics of blood feeding, resulting in regurgitative transmission. Many of the important genes, regulatory pathways, and molecules required for this process have been identified and are reviewed here.

Recombinant Fusion Protein Joining E Protein Domain III of Tick-Borne Encephalitis Virus and HSP70 of Yersinia pseudotuberculosis as an Antigen for the TI-Complexes

Domain III (DIII) of the tick-borne encephalitis virus (TBEV) protein E contains epitopes, which induce antibodies capable of neutralizing the virus. To enhance the immunogenicity of this protein, which has a low molecular weight, the aim of the present work was to express, isolate, and characterize a chimeric protein based on the fusion of the bacterial chaperone HSP70 of Yersinia pseudotuberculosis and EIII (DIII + stem) as a prospective antigen for an adjuvanted delivery system, the tubular immunostimulating complex (TI-complex). The chimeric construction was obtained using pET-40b(+) vector by ligating the respective genes. The resulting plasmid was transformed into DE3 cells for the heterologous expression of the chimeric protein, which was purified by immobilized metal affinity chromatography (IMAC). ELISA, differential scanning calorimetry, intrinsic fluorescence, and computational analysis were applied for the characterization of the immunogenicity and conformation of the chimeric protein. Mice immunization showed that the chimeric protein induced twice the number of anti-EIII antibodies in comparison with EIII alone. In turn, the incorporation of the HSP70/EIII chimeric protein in the TI-complex resulted in a twofold increase in its immunogenicity. The formation of this vaccine construction was accompanied by significant conformational changes in the chimeric protein. Using HSP70 in the content of the chimeric protein represents an efficient means for presenting the main antigenic domain of the TBEV envelope protein to the immune system, whereas the incorporation of this chimeric protein into the TI-complex further contributes to the development of a stronger immune response against the TBEV infection.

Yersiniosis in Poland in 2014

OBJECTIVE

The aim of the study is to present the epidemiological situation of yersiniosis in Poland in 2014 and compare it with the situation in the previous years.

MATERIAL AND METHODS

The evaluation was based on analysis of data from the annual bulletins “Infectious diseases and poisoning in Poland” for the period 2009-2014 (MP Czarkowski et al., National Institute of Hygiene and GIS – Chief Sanitary Inspectorate), interviews of individual yersiniosis cases, sent by the sanitary-epidemiological stations from the whole country and the data on deaths from the Department of Demographic Studies of the Central Statistical Office.

RESULTS

In 2014 in Poland 244 cases of yersiniosis were recorded (0.63/100 000). Among them 241 infections were caused by Y. enterocolitica and 3 by Y. pseudotuberculosis. There were 215 cases of intestinal yersiniosis and 29 of extraintestinal. Hospitalization required 59.8% of patients. There were no deaths reported which cause was infection with Yersinia. Intestinal yersiniosis was manifested the mostly by symptoms as follow: diarrhea (88%, including 8% with blood in stool), fever (66%), abdominal pain (49%) and vomiting (22%). The most of the cases (131 - approx. 61%) of intestinal yersiniosis occurred among children in the age group 0-4 years . Number of extra intestinal Yersinia infections (20 cases) was higher than in 2013. The most frequent symptom of those cases was osteoarticular pain, which was observed in 79% of patients. As in 2013 most cases of intestinal yersiniosis were reported from the Mazowieckie voivodeship (104 cases). Serological type of Yersinia was determined only in 58 (24%) cases. This percentage was the lowest since the start of registration of yersiniosis in the country in the year 2006. The identified serotypes were O3 (88%) O8 (6.9%) and O9 (5.2%). In 2014, 4 cases of infection with “American” serotype O8 were identify. One family outbreak caused by Yersinia spp occurred in 2014.

CONCLUSIONS

A significant decrease of serologically identified cases of yersinia observed in 2014. could be explained by the test for Yersinia not being reimbursed by routine health care insurance. Reporting cases of extraintestinal yersiniosis from only few voivodeships suggests that the real number of infections remains underreported. In 2014 significantly higher number of cases of Yersinia infection occurred during the second and third quarter of the year. Seasonality of yersiniosis in 2014 differs from seasonality in 2013. However, it was similar to the seasonality observed in previous years (2009-2012).

The influence of monogalactosyldiacylglycerols from different marine macrophytes on immunogenicity and conformation of protein antigen of tubular immunostimulating complex

The tubular immunostimulating complex (TI-complex) is a novel nanoparticulate antigen delivery system consisting of cholesterol, triterpene glycoside cucumarioside A(2)-2, and glycolipid monogalactosyldiacylglycerol (MGDG) isolated from marine macrophytes. MGDG is crucial for the formation of a lipid matrix for the protein antigen incorporated in TI-complexes. Fatty acid composition and the physical state of this glycolipid depend on the taxonomic position of marine macrophytes. Therefore, the aim of the present work was to study the capacity of MGDGs, isolated from five species of marine macrophytes, to influence conformation and to enhance immunogenicity of porin from Yersinia pseudotuberculosis (YOmpF) as a model antigen of subunit vaccine based on TI-complexes. The trimeric porin was chosen for these experiments, because it was approximately two times more immunogenic than monomeric porin incorporated in TI-complexes. Immunization of mice with YOmpF within TI-complexes, comprised of different MGDGs, revealed a dependence of the immunostimulating effect of TI-complexes on the microvicosity of this glycolipid. TI-complexes comprising MGDGs from Sargassum pallidum and Ulva fenestrata with medium microviscosity induced maximal levels of anti-porin antibodies (four times higher when compared with those induced by pure porin). The adjuvant effect of TI-complexes based on other MGDGs varied by 2.8, 2.3 and 1.3 times for TI-complexes comprised of MGDGs from Zostera marina, Ahnfeltia tobuchiensis, and Laminaria japonica, respectively. MGDGs are also able to influence cytokine mechanisms of immunological regulation. DSC and spectroscopic studies showed that maximal immunostimulating effect of TI-complexes correlated with a moderate stabilizing influence of MGDGs from S. pallidum and U. fenestrata on the conformation of porin. The results obtained suggest lipid "nanofluidics" as a novel strategy for optimizing the immune response to protein antigens within lipid particulate systems.

Cytotoxic Necrotizing Factors (CNFs)-A Growing Toxin Family

The Escherichia coli Cytotoxic Necrotizing Factors, CNF1, CNF2, CNF3 and CNFY from Yersinia pseudotuberculosis belong to a family of deamidating toxins. CNFs deamidate glutamine 63/61 in the switch II region of Rho GTPases that is essential for GTP hydrolysing activity. Deamidation leads to constitutive activation of Rho GTPases. However, cellular mechanisms like proteasomal degradation of the activated Rho proteins restrict the action of the GTPases. This review describes the differences between the toxin family members concerning expression, cellular entry and substrate specificity.

[Influence of thermolabile lethal toxin of Yersinia pseudotuberculosis on development of sea urchin embryos and biosynthesis of DNA and RNA in embryonic cells]

Influence of thermolabile lethal toxin of Y. pseudotuberculosis on the development of embryos of sea urchin (Strongylocentrotus intermedius) and on biosynthesis of nucleic acids in embryonic cells was studied. Thermolabile lethal toxin affected metabolic processes of cells by inhibiting DNA and RNA synthesis. It had damaging action on developing embryos of sea urchin causing morphological changes and, as a consequence, death of embryos.

Forming and immunological properties of some lipopolysaccharide–chitosan complexes

The complex formation of lipopolysaccharide (LPS) with chitosan (Ch) was demonstrated using sedimentation velocity analysis in the analytical ultracentrifuge, centrifugation in glycerol gradient and isopicnic centrifugation in cesium chloride. An addition of Ch to the Escherichia coli and Yersinia pseudotuberculosis LPS solutions was found to result in formation of the stable LPS-Ch complexes. The interaction is a complicated process and depends on time and reaction temperature, as well as on the molecular weight of chitosan. A stable LPS-Ch complex could be formed only after preliminary incubation of the initial components at an elevated temperature (37 degrees C). It should be noted that process of LPS complexation with Ch is accompanied by additional dissociating of LPS. The complex formation was shown to be a result not only of ionic binding, but also of other types of interactions. The interaction of Ch with LPS was shown to modulate significantly the biological activity of LPS. The LPS-Ch complex (1:5 w/w) was shown to possess much lower toxicity in a comparison with the parent LPS at injection to mice in the similar concentration. The LPS-Ch complex was shown to maintain an ability to induce of IL-8 and TNF, but induction of IL-8 and TNF biosynthesis by the LPS-Ch complex was lower than that by the parent LPS. The complex LPS-Ch, similarly to the parent LPS, was found stimulated the formation of the IL-8 in the dose-dependent manner in the human embryonal kidney cells (HEK 293 cells) transfected with TLR4 in combination with MD2.

Induction of CD8+ T cell responses by Yersinia vaccine carrier strains

Yersinia enterocolitica employs a type III secretion system (TTSS) to target virulence factors (e.g. YopE) into the cytosol of the host cells. We utilized the TTSS to introduce a recombinant antigen directly into the cytosol of host cells and to investigate the potential of Y. enterocolitica and Y. pseudotuberculosis as live carrier for vaccines. The model antigen ovalbumin (Ova) was fused to defined secretion or translocation domains of the Yersinia effector protein YopE and introduced into attenuated mutant strains of Y. enterocolitica and Y. pseudotuberculosis. In vitro experiments showed secretion and translocation of YopE-Ova hybrid proteins into host cells. To investigate the resulting immune responses, mice expressing transgenic Ova-specific T cell receptors were used. Both Y. enterocolitica and Y. pseudotuberculosis mutants induced efficaciously Ova-specific CD8+ T cell responses. The translocation domain of YopE was required for induction of CD8+ T cell responses in vivo, but not for T cell responses induced in vitro. The in vivo frequency of Ova-specific splenic T cells was up to six-fold higher in mice immunized with YopE-Ova-translocating Y. enterocolitica/Y. pseudotuberculosis mutants than in control mice. The Ova-specific T cells were shown to produce high amounts of IFN-gamma. We did not observe significant Ova-specific CD4+ T cell or antibody responses upon vaccination with either of the strains. In conclusion, Yersinia live carrier vaccine strains are suitable to target antigens into the MHC class I pathway and stimulate CD8+ T cell responses and thus, might be useful in vaccine approaches against intracellular pathogens.

Subcellular proteomic analysis of host-pathogen interactions using human monocytes exposed toYersinia pestis andYersinia pseudotuberculosis

Yersinia pestis, the etiological agent of plague, is of concern to human health both from an infectious disease and a biodefense perspective. While Y. pestis and Yersinia pseudotuberculosis share more than 90% DNA homology, they have significantly different clinical manifestations. Plague is often fatal if untreated, yet Y. pseudotuberculosis causes severe intestinal distress but is rarely fatal. A better understanding of host response to these closely related pathogens may help explain the different mechanisms of virulence and pathogenesis that result in such different clinical outcomes. The aim of this study was to characterize host protein expression changes in human monocyte U937 cells after exposure to Y. pestis and Y. pseudotuberculosis. In order to gain global proteomic coverage of host response, proteins from cytoplasmic, nuclear and membrane fractions of host cells were studied by two-dimensional differential gel electrophoresis and relative protein expression differences were quantitated. Differentially expressed proteins, with at least 1.5-fold expression changes and p values of 0.01 or less, were identified by mass spectrometry including matrix-assisted laser desorption/ionization-MS or liquid chromatography tandem mass spectrometry. With these criteria, differential expression was detected in 16 human proteins after Y. pestis exposure and 13 human proteins after Y. pseudotuberculosis exposure, of which only two of the differentially expressed proteins identified were shared between the two exposures. Proteins identified in this study are reported to be involved in a wide spectrum of cellular functions and host defense mechanisms including apoptosis, cytoskeletal rearrangement, protein synthesis and degradation, DNA replication and transcription, metabolism, protein folding, and cell signaling. Notably, the differential expression patterns observed can distinguish the two pathogen exposures from each other and from unexposed host cells. The functions of the differentially expressed proteins identified provide insight on the different virulence and pathogenic mechanisms of Y. pestis and Y. pseudotuberculosis.

Engineered E. coli delivers therapeutic genes to the colonic mucosa

Taking advantage of the proximity of bowel mucosa to luminal bacteria, we have attempted to deliver a therapeutic gene to the colonic mucosa by oral administration of an invasive and non-pathogenic Escherichia coli. E. coli diamenopimelate (dap) auxotroph, harboring plasmid pGB2Omegainv-hly, express the inv gene from Yersinia pseudotubercolosis that confers the ability to invade nonprofessional phagocytic cells and the hly gene from Listeria monocytogenes that allows expression of lystreriolysin O, a perforin cytolysin able to perfore phagosomal membranes. This bacterial vector invades and transfers functional DNA to epithelial cells in vitro. We have shown that this strain carrying a therapeutic gene (pC1OmegaTGF-beta1) can significantly reduce the severity of experimental colitis in mice. However, as a consequence of mucosal barrier disruption during colitis, vector-specific mRNA transcripts could be recovered from the colon and also from extra-colonic tissues. We therefore replaced the constitutive CMV promoter in pC1OmegaTGF-beta1 by the inflammation-inducible interleukin-8 promoter generating plasmid pC1OmegaTGF-beta1IND. Plasmid-specific TGF-beta1 mRNA transcripts were detectable in mouse CMT-93 epithelial cells incubated with E. coli BM2710/pGB2Omegainv-hly carrying pC1OmegaTGF-beta1IND following exposure to inflammatory cytokines. Furthermore, the transcripts were detectable only within inflamed tissues and the therapeutic effects were comparable to those in animals treated with E. coli BM2710/pGB2Omegainv-hly+pC1OmegaTGF-beta1. In summary, engineered enteric bacteria can efficiently deliver in vivo therapeutic genes to the intact intestinal mucosa and regulation expression of the therapeutic gene by an inflammation-inducible promoter prevents its dissemination during colitis.

[Experimental morphological study of the therapeutic effect of shark cartilage preparation in a model of infective allergic arthritis]

The therapeutic effect of a Polar shark cartilage preparation which is an enzymatic hydrolysate was studied in a rabbit model of infective allergic pseudotuberculous arthritis. Characterization of the chemical composition of the preparation designed by an original method is presented. Improvement of the general state of the affected joints and development of tissue immunomorphological responses were shown.

[Method for the calculation of the 50% effective dose of biologically active agents]

A newly proposed method for the mathematical and graphic determination and calculation of ED50 (LD50) on the abscissa at the meeting point of the cumulate of dead and the cumulate of survived animals (in absolute figures) in "dose-effect) experiments is described. "The method of meeting cumulates) for the calculation of ED50 (LD50) is simple, eliminates unnecessary calculations, yields results, highly similar (95-100%) to those obtained by other methods and may be used in different medico-biological studies.

Loss of srf-3-encoded nucleotide sugar transporter activity in Caenorhabditis elegans alters surface antigenicity and prevents bacterial adherence

During the establishment of a bacterial infection, the surface molecules of the host organism are of particular importance, since they mediate the first contact with the pathogen. In Caenorhabditis elegans, mutations in the srf-3 locus confer resistance to infection by Microbacterium nematophilum, and they also prevent biofilm formation by Yersinia pseudotuberculosis, a close relative of the bubonic plague agent Yersinia pestis. We cloned srf-3 and found that it encodes a multitransmembrane hydrophobic protein resembling nucleotide sugar transporters of the Golgi apparatus membrane. srf-3 is exclusively expressed in secretory cells, consistent with its proposed function in cuticle/surface modification. We demonstrate that SRF-3 can function as a nucleotide sugar transporter in heterologous in vitro and in vivo systems. UDP-galactose and UDP-N-acetylglucosamine are substrates for SRF-3. We propose that the inability of Yersinia biofilms and M. nematophilum to adhere to the nematode cuticle is due to an altered glycoconjugate surface composition of the srf-3 mutant.

Yersinia pestis and plague

Yersinia pestis is the aetiological agent of plague, a disease of humans that has potentially devastating consequences. Evidence indicates that Y. pestis evolved from Yersinia pseudotuberculosis, an enteric pathogen that normally causes a relatively mild disease. Although Y. pestis is considered to be an obligate pathogen, the lifestyle of this organism is surprisingly complex. The bacteria are normally transmitted to humans from a flea vector, and Y. pestis has a number of mechanisms which allow survival in the flea. Initially, the bacteria have an intracellular lifestyle in the mammalian host, surviving in macrophages. Later, the bacteria adopt an extracellular lifestyle. These different interactions with different host cell types are regulated by a number of systems, which are not well characterized. The availability of the genome sequence for this pathogen should now allow a systematic dissection of these regulatory systems.

[Use of immunomodulators isolated from marine invertebrates for reducing the toxic effects of thermostable toxin and lipopolysaccharides from Yersinia pseudotuberculosis on a macroorganism]

The possibility to use immunomodulators isolated from marine invertebrates for the lowering of the toxic effects caused by Yersinia pseudotuberculosis thermoresistant toxin and lipopolysaccharide was investigated. Effects were evaluated by the animals survival rate in per cent and mice average lifetime after toxin lethal dose injection. It was shown that polypeptide gangleen when compared to timalin as well as glycanes mitilane and strombus had dose-dependent protective effect. These substances increased animals survival rate to 15-17 per cent and prolonged life period for about two times when compared to control group. These results demonstrates the possibility to use investigated immunomodulators is clinical practice at the treatment of the patients with pseudotuberculosis.

Exoenzyme T of Pseudomonas aeruginosa elicits cytotoxicity without interfering with Ras signal transduction

One virulence strategy used by the opportunistic pathogen Pseudomonas aeruginosa is to target toxic proteins into eukaryotic cells by a type III secretion mechanism. Two of these proteins, ExoS and ExoT, show 75% homology on amino acid level. However, compared with ExoS, ExoT exhibits highly reduced ADP-ribosylating activity and the role of ExoT in pathogenesis is poorly understood. To study the biological effect of ExoT, we used a strategy by which ExoT was delivered into host cells by the heterologous type III secretion system of Yersinia pseudotuberculosis. ExoT was found to induce a rounded cell morphology and to mediate disruption of actin microfilaments, similar to that induced by an ADP-ribosylation defective ExoS (E381A) and the related cytotoxin YopE of Y. pseudotuberculosis. In contrast to ExoS, ExoT had no major effect on cell viability and did not modify or inactivate Ras by ADP-ribosylation in vivo. However, similar to ExoS and YopE, ExoT exhibited GAP (GTPase activating protein) activity on RhoA GTPase in vitro. Interestingly, ExoT(R149K), deficient for GAP activity, still caused a morphological change of HeLa cells. Based on our findings, we suggest that the ADP-ribosylating activity of ExoT target another, as yet unidentified, host protein that is distinct from Ras.

Pathomorphological characteristics of experimental toxemia induced by thermostable Yersinia pseudotuberculosis toxin

Pathogenic properties of thermostable toxin responsible for pathogenicity of Yersinia pseudotuberculosis were experimentally studied. The toxin exerted a pronounced polyorgan cytopathogenic effect with predominating degenerative destructive changes and membranolytic effect on cell ultrastructure of parenchymatous organs. The toxin is believed to be directly involved in the development of typical pathomorphological picture of pseudotuberculosis, which confirms its pathogenetic role.

The pathogenesis of Kawasaki disease and superantigens

Kawasaki disease (KD) is an acute febrile illness in infants and children with systemic clinical symptoms, including coronary artery aneurysms. Findings seen in KD patients such as infiltration of T cells into vascular lesions, elevation of soluble interleukin 2 receptors in serum, an imbalance of T cell subsets, and transient depletion of T cells with CD11/CD18 suggest that the activation of T cells is involved in the pathogenesis of KD. In 1992, an interesting mechanism was proposed in which T cell activation by a certain superantigen is involved in the pathogenesis of KD. Examinations have been undertaken extensively to confirm the proposed hypothesis. We, however, still do not have reliable evidence supporting the above hypothesis. In the present paper we review the research papers which support or rule out the view described above. In addition, we discuss the relation between KD and systemic Yersinia pseudotuberculosis infection that manifests clinical symptoms quite similar to those in KD.

A complex composed of SycN and YscB functions as a specific chaperone for YopN in Yersinia pestis

Human pathogenic Yersinia resist host defences, in part through the expression and delivery of a set of plasmid-encoded virulence proteins termed Yops. A number of these Yops are exported from the bacteria directly into the cytoplasm of their eukaryotic host's cells upon contact with these cells. The secreted YopN protein (also known as LcrE) is required to block Yop secretion in the presence of calcium in vitro or before contact with a eukaryotic cell in vivo. In this study, we characterize the role of the tyeA, sycN and yscB gene products in the regulation of Yop secretion in Yersinia pestis. Mutants specifically defective in the expression of TyeA, SycN or YscB were no longer able to block Yop secretion in the presence of calcium. In addition, the secretion of YopN was specifically reduced in both the sycN and the yscB deletion mutants. Protein cross-linking and immunoprecipitation studies in conjunction with yeast two-hybrid analyses showed that SycN and YscB interact with one another to form a SycN/YscB complex. Yeast three-hybrid analyses demonstrated that the SycN/YscB complex, but not SycN or YscB alone, specifically associates with YopN. SycN and YscB share amino acid sequence similarity and structural similarities with the specific Yop chaperones SycE and SycH. Together, these results indicate that a complex composed of SycN and YscB functions as a specific chaperone for YopN in Y. pestis.

[Effect of the thermostable toxin of Yersinia pseudotuberculosis on the oxidant and antioxidant activity of human blood leukocytes]

Y.pseudotuberculosis thermostable lethal toxin as shown to affect the functional activity of human blood leukocytes. Still neutrophils and monocytes exhibited different reaction to the introduction of the toxin. In monocytes, the toxin in a dose of 0.2 microgram/4 x 10(4) cells inhibited the formation of active forms of oxygen (AFO) and activated the production of superoxide dismutase (SOD). In neutrophils, the toxin affected only the activity of glutathione reductase, inducing a decrease in its activity. The toxin, depending on its dose, stimulated a rise in the level of cyclic adenosine monophosphate (cAMP) in mononuclear cells, but inhibited it in neutrophils. When the toxin was introduced together with indomethacin (10(-7) M), the level of cAMP increased in mononuclears and decreased in neutrophils in comparison with the action of the toxin, introduced alone. Indomethacin prevented the action of the toxin on mononuclears with respect to AFO, SOD and cAMP, which was indicative of the mediating role of prostaglandins in the mechanism of the action of the toxin.

The bacterial outer membrane protein that reacts with anti-HLA-B27 antibodies is the OmpA protein

A bacterial outer membrane protein of 35-kDa Mr has been reported to react with several anti-HLA-B27 mAb. Here, we demonstrated that this protein showed the heat-modifiability of the OmpA protein during SDS-PAGE. Further, the protein was not detected in mutants of Escherichia coli in which the expression of the OmpA protein has been suppressed. The protein would be reexpressed when one of the mutants was transformed with an expression vector carrying the OmpA gene. Finally, the identity of the reactive protein to OmpA protein was verified by homology in amino acid sequences. An NH2-terminal fragment of this protein was generated by tryptic digestion. Inasmuch as this was unreactive with the anti-HLA-B27 antibody, we concluded that the carboxyl-terminus contributed directly or indirectly to the reactive domain.

[Isolation and physico-chemical properties of a protein, included in an endotoxin from Yersinia pseudotuberculosis]

A major protein of the endotoxin from Yersinia pseudotuberculosis was isolated from the complex lipid A--protein by treatment with SDS and triton X-100 followed by gel-chromatography on Sephacryl S-300. Protein has apparent molecular mass 40 kDa and alanine as N-terminal amino acid residue. CD and IR spectroscopy conformational changes of the protein molecule in the process of its isolation. The thermal and pH stabilities of the protein were investigated by the methods of intrinsic fluorescence and differential scanning microcalorimetry. The isolated protein revealed two thermal transitions (at 30-35 and 50-55 degrees C), which depend on Ca2+ concentration.

Post-yersinial arthritis in Cleveland, England

Four cases of post-yersinial reactive arthritis are described. All patients presented with an acute lower limb arthropathy with features of an associated enthesopathy. Two patients had restriction of axial skeletal movements. Systemic features were prominent in three, including weight loss and malaise. Mean age of onset was 34 years. Three patients gave a history of antecedent diarrhoea within the previous month. Three patients had raised titres to Y enterocolitica type 0:3 (ranging from 1 in 320 to 1 in 2560) and one had raised titres to Y pseudotuberculosis type 2 at 1 in 640. Two of the three patients with Y enterocolitica reactive arthritis ran a chronic course with low grade arthropathy of lower limbs and back stiffness. One patient developed radiological sacroiliitis at two years, and two patients had an increased sacroiliac index, though x rays of the sacroiliac joints were normal. The patient with Y pseudotuberculosis reactive arthritis had a self limiting disease with spontaneous resolution over six months.

Experimental Yersinia-associated arthritis in the spontaneously hypertensive rat

Sterile arthritis resembling human reactive arthritis was induced in spontaneously hypertensive SHR rats by intravenous injection of live Yersinia enterocolitica 0:8. Histologically the synovitis appears as proliferation of the lining cell layer, with inflammatory cells present in the subsynovium. The inflammatory cells are mostly lymphocytes. Infection with Yersinia enterocolitica 0:3 or Yersinia pseudotuberculosis did not induce arthritis. Susceptibility to Yersinia-associated arthritis is not determined by the major histocompatibility complex (MHC), since rats of the normotensive control strain (WKY) with the same MHC do not develop arthritis.

Yersinia pseudotuberculosis sepsis presenting as multiple liver abscesses

A 50-year-old man with diabetes was found to have sepsis with multiple small hepatic abscesses secondary to Yersinia pseudotuberculosis which were detected by computed tomography (CT) scan. Sepsis with Y. pseudotuberculosis is uncommon but usually seen in patients with underlying liver disease. Those patients with liver abscesses invariably have multiple small abscesses. Widespread use of CT scanning is likely to uncover more cases of hepatic microabscesses; in the appropriate clinical setting, Y. pseudotuberculosis should be considered as a possible cause.

Yersinia-associated arthritis in the rat: experimental model for human reactive arthritis?

Rats of five different strains were injected intravenously with live Yersinia enterocolitica O:8 or Yersinia pseudotuberculosis III. Twelve to 18 days after inoculation of Y. enterocolitica O:8, arthritic symptoms appeared in the hindpaws of SHR rats. They started with erythema, followed by swelling and painful movement, closely resembling findings in adjuvant arthritis. Histologically, the inflammation was dominated by neutrophils in two cases, whereas in two others the inflammatory cells were predominantly lymphocytes. Two of five rats yielded positive bacterial cultures from the joints. Altogether, arthritis was observed in five of nine SHR surviving beyond day 14 after the bacterial inoculation. Rats of Lewis, Wistar, WKY and Zucker strains did not develop any signs of arthritis after intravenous injection of Y. enterocolitica or pseudotuberculosis. Also in the SHR rats, Y. pseudotuberculosis failed to induce arthritis.