scholarly journals Naturally Occurring IgG Antibodies Provide Innate Protection against Vibrio cholerae Bacteremia by Recognition of the Outer Membrane Protein U

2016 ◽  
Vol 8 (3) ◽  
pp. 269-283 ◽  
Author(s):  
Kyaw Min Aung ◽  
Annika E. Sjöström ◽  
Ulrich von Pawel-Rammingen ◽  
Kristian Riesbeck ◽  
Bernt Eric Uhlin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Outer Membrane Protein ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Immune Defense ◽  
Dependent Manner ◽  
Naturally Occurring ◽  
Serum Killing

Cholera epidemics are caused by Vibrio cholerae serogroups O1 and O139, whereas strains collectively known as non-O1/non-O139 V. cholerae are found in cases of extraintestinal infections and bacteremia. The mechanisms and factors influencing the occurrence of bacteremia and survival of V. cholerae in normal human serum have remained unclear. We found that naturally occurring IgG recognizing V. cholerae outer membrane protein U (OmpU) mediates a serum-killing effect in a complement C1q-dependent manner. Moreover, outer membrane vesicles (OMVs) containing OmpU caused enhanced survival of highly serum-sensitive classical V. cholerae in a dose-dependent manner. OMVs from wild-type and ompU mutant V. cholerae thereby provided a novel means to verify by extracellular transcomplementation the involvement of OmpU. Our data conclusively indicate that loss, or reduced expression, of OmpU imparts resistance to V. cholerae towards serum killing. We propose that the difference in OmpU protein levels is a plausible reason for differences in serum resistance and the ability to cause bacteremia observed among V. cholerae biotypes. Our findings provide a new perspective on how naturally occurring antibodies, perhaps induced by members of the microbiome, may play a role in the recognition of pathogens and the provocation of innate immune defense against bacteremia.

scholarly journals Protein-enriched outer membrane vesicles as a native platform for outer membrane protein studies

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Johannes Thoma ◽  
Selen Manioglu ◽  
David Kalbermatter ◽  
Patrick D. Bosshart ◽  
Dimitrios Fotiadis ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles

scholarly journals Immunization With Outer Membrane Vesicles Derived From Major Outer Membrane Protein-Deficient Salmonella Typhimurium Mutants for Cross Protection Against Salmonella Enteritidis and Avian Pathogenic Escherichia coli O78 Infection in Chickens

2020 ◽  
Vol 11 ◽  
Author(s):  
Yuxuan Chen ◽  
Kaiwen Jie ◽  
Biaoxian Li ◽  
Haiyan Yu ◽  
Huan Ruan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Broad Spectrum ◽  
Outer Membrane Protein ◽  
Salmonella Enteritidis ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Major Outer Membrane Protein ◽  
Cross Protection

Colibacillosis is an economically important infectious disease in poultry, caused by avian pathogenic Escherichia coli (APEC). Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne diseases in human circulated through poultry-derived products, including meat and chicken eggs. Vaccine control is the mainstream approach for combating these infections, but it is difficult to create a vaccine for the broad-spectrum protection of poultry due to multiple serotypes of these pathogens. Our previous studies have shown that outer membrane vesicles (OMVs) derived from S. enterica serovar Typhimurium mutants with a remodeled outer membrane could induce cross-protection against heteroserotypic Salmonella infection. Therefore, in this study, we further evaluated the potential of broad-spectrum vaccines based on major outer membrane protein (OMP)-deficient OMVs, including ΔompA, ΔompC, and ΔompD, and determined the protection effectiveness of these candidate vaccines in murine and chicken infection models. The results showed that ΔompA led to an increase in the production of OMVs. Notably, ΔompAΔompCΔompD OMVs showed significantly better cross-protection against S. enterica serovar Choleraesuis, S. Enteritidis, APEC O78, and Shigella flexneri 2a than did other omp-deficient OMVs, with the exception of ΔompA OMVs. Subsequently, we verified the results in the chicken model, in which ΔompAΔompCΔompD OMVs elicited significant cross-protection against S. Enteritidis and APEC O78 infections. These findings further confirmed the feasibility of improving the immunogenicity of OMVs by remodeling the outer membrane and provide a new perspective for the development of broad-spectrum vaccines based on OMVs.

scholarly journals Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival ofVibrio choleraeand Suppresses Viability ofAcanthamoeba castellanii

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Soni Priya Valeru ◽  
Salah Shanan ◽  
Haifa Alossimi ◽  
Amir Saeed ◽  
Gunnar Sandström ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Host Cells ◽  
Wild Type ◽  
Outer Membrane Protein A

Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive insideAcanthamoeba castellanii. It has been shown thatV. choleraeexpresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA) and outer membrane vesicles (OMVs) in survival ofV. choleraealone and during its interaction withA. castellanii. The results showed that anOmpAmutant ofV. choleraesurvived longer than wild-typeV. choleraewhen cultivated alone. Cocultivation withA. castellaniienhanced the survival of both bacterial strains andOmpAprotein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of theOmpAmutant ofV. choleraedecreased the viability ofA. castellaniiand this bacterial strain released more OMVs than wild-typeV. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from theOmpAmutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule forOmpAin survival ofV. choleraeand OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment.

scholarly journals Acinetobacter baumannii Secretes Cytotoxic Outer Membrane Protein A via Outer Membrane Vesicles

PLoS ONE ◽  
2011 ◽  
Vol 6 (2) ◽  
pp. e17027 ◽  
Author(s):  
Jong Sook Jin ◽  
Sang-Oh Kwon ◽  
Dong Chan Moon ◽  
Mamata Gurung ◽  
Jung Hwa Lee ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Outer Membrane Protein A

Acinetobacter baumannii outer membrane protein a modulates the biogenesis of outer membrane vesicles

2012 ◽  
Vol 50 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Dong Chan Moon ◽  
Chul Hee Choi ◽  
Jung Hwa Lee ◽  
Chi-Won Choi ◽  
Hye-Yeon Kim ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Outer Membrane Protein A

scholarly journals The Helicobacter pylori Autotransporter ImaA (HP0289) Modulates the Immune Response and Contributes to Host Colonization

2012 ◽  
Vol 80 (7) ◽  
pp. 2286-2296 ◽  
Author(s):  
William E. Sause ◽  
Andrea R. Castillo ◽  
Karen M. Ottemann
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Content Type ◽  
H Pylori ◽  
Murine Infections

ABSTRACTThe human pathogenHelicobacter pyloriemploys a diverse collection of outer membrane proteins to colonize, persist, and drive disease within the acidic gastric environment. In this study, we sought to elucidate the function of the host-induced geneHP0289, which encodes an uncharacterized outer membrane protein. We first generated an isogenicH. pylorimutant that lacksHP0289and found that the mutant has a colonization defect in single-strain infections and is greatly outcompeted in mouse coinfection experiments with wild-typeH. pylori. Furthermore, we used protease assays and biochemical fractionation coupled with an HP0289-targeted peptide antibody to verify that the HP0289 protein resides in the outer membrane. Our previous findings showed that theHP0289promoter is upregulated in the mouse stomach, and here we demonstrate thatHP0289expression is induced under acidic conditions in an ArsRS-dependent manner. Finally, we have shown that theHP0289mutant induces greater expression of the chemokine interleukin-8 (IL-8) and the cytokine tumor necrosis factor alpha (TNF-α) in gastric carcinoma cells (AGS). Similarly, transcription of the IL-8 homolog keratinocyte-derived chemokine (KC) is elevated in murine infections with the HP0289 mutant than in murine infections with wild-typeH. pylori. On the basis of this phenotype, we renamed HP0289 ImaA forimmunomodulatoryautotransporter protein. Our work has revealed that genes inducedin vivoplay an important role inH. pyloripathogenesis. Specifically, the outer membrane protein ImaA modulates a component of the host inflammatory response, and thus may allowH. pylorito fine tune the host immune response based on ImaA expression.

Structural features, properties and regulation of the outer-membrane protein W (OmpW) of Vibrio cholerae

Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 2975-2986 ◽  
Author(s):  
Bisweswar Nandi ◽  
Ranjan K. Nandy ◽  
Amit Sarkar ◽  
Asoke C. Ghose
Keyword(s):  
Membrane Protein ◽  
Recombinant Protein ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Outer Membrane Protein ◽  
Secondary Structure Prediction ◽  
Sequence Data ◽  
Insertion Mutagenesis ◽  
Sds Page

The outer-membrane protein OmpW of Vibrio cholerae was studied with respect to its structure, functional properties and regulation of expression. On SDS-PAGE, the membrane-associated form of OmpW protein (solubilized by either 0·1 % or 2 % SDS at 25 °C) migrated as a monomer of 19 kDa that changed to 21 kDa on boiling. The protein was hyperexpressed in Escherichia coli in the histidine-tagged form and the purified His6-OmpW (heated or unheated) migrated as a 23 kDa protein on SDS-PAGE. Circular dichroism and Fourier-transform infrared spectroscopic analyses of the recombinant protein showed the presence of β-structures (∼40 %) with minor amounts (8–15 %) of α-helix. These results were consistent with those obtained by computational analysis of the sequence data of the protein using the secondary structure prediction program Jnet. The recombinant protein did not exhibit any porin-like property in a liposome-swelling assay. An antiserum to the purified protein induced a moderate level (66·6 % and 33·3 % at 1 : 50 and 1 : 100 dilutions, respectively) of passive protection against live vibrio challenge in a suckling mouse model. OmpW-deficient mutants of V. cholerae strains were generated by insertion mutagenesis. In a competitive assay in mice, the intestinal colonization activities of these mutants were found to be either only marginally diminished (for O1 strains) or 10-fold less (for an O139 strain) as compared to those of the corresponding wild-type strains. The OmpW protein was expressed in vivo as well as in vitro in liquid culture medium devoid of glucose. Interestingly, the glucose-dependent regulation of OmpW expression was less prominent in a ToxR− mutant of V. cholerae. Further, the expression of OmpW protein was found to be dependent on in vitro cultural conditions such as temperature, salinity, and availability of nutrients or oxygen. These results suggest that the modulation of OmpW expression by environmental factors may be linked to the adaptive response of the organism under stress conditions.

scholarly journals Cholera Toxin Encapsulated within Several Vibrio cholerae O1 Serotype Inaba Outer Membrane Vesicles Lacks a Functional B-Subunit

Toxins ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 207 ◽  
Author(s):  
Elnaz Rasti ◽  
Angela Brown
Keyword(s):  
Outer Membrane ◽  
Cholera Toxin ◽  
Vibrio Cholerae ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Biologically Active ◽  
Host Cells ◽  
Free Form ◽  
Type Ii Secretion ◽  
Secondary Mechanism

Cholera toxin (CT), the major virulence factor of Vibrio cholerae, is an AB5 toxin secreted through the type II secretion system (T2SS). Upon secretion, the toxin initiates endocytosis through the interaction of the B pentamer with the GM1 ganglioside receptor on small intestinal cells. In addition to the release of CT in the free form, the bacteria secrete CT in association with outer membrane vesicles (OMVs). Previously, we demonstrated that strain 569B releases OMVs that encapsulate CT and which interact with host cells in a GM1-independent mechanism. Here, we have demonstrated that OMV-encapsulated CT, while biologically active, does not exist in an AB5 form; rather, the OMVs encapsulate two enzymatic A-subunit (CTA) polypeptides. We further investigated the assembly and secretion of the periplasmic CT and found that a major fraction of periplasmic CTA does not participate in the CT assembly process and instead is continuously encapsulated within the OMVs. Additionally, we found that the encapsulation of CTA fragments in OMVs is conserved among several Inaba O1 strains. We further found that under conditions in which the amount of extracellularly secreted CT increases, the concentration of OMV-encapsulated likewise CTA increases. These results point to a secondary mechanism for the secretion of biologically active CT that does not depend on the CTB-GM1 interaction for endocytosis.

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