scholarly journals Evaluation of antibody responses to outer membrane vesicles (OMVs) and killed whole cell of Vibrio cholerae O1 El Tor in immunized mice

2019 ◽  
Author(s):  
Manijeh Sedaghat ◽  
Seyed Davar Siadat ◽  
Esmat Mirabzadeh ◽  
Malihe Keramati ◽  
Farzam Vaziri ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Membrane Vesicles ◽  
Intestinal Secretion ◽  
Oral Immunization ◽  
Outer Membrane Vesicles ◽  
Clinical Strain ◽  
Whole Cell ◽  
Vibrio Cholerae O1 ◽  
El Tor

Background and Objectives: Cholera disease remains an important global health problem affecting 3-5 million subjects worldwide. Outer membrane vesicles (OMVs) have been found in a variety of Gram-negative bacteria and act as protective transport vesicles. The aim of this study was to evaluate Immune responses against Vibrio cholerae O1 El Tor clinical strain OMV and compare it with killed whole cell (KWC), complex of (KWC-OMV) as well as the internationally licensed oral cholera vaccine, Dukoral, in serum and intestinal secretions of mice. Materials and Methods: OMVs were prepared by using modified detergent-centrifugation procedure from V. cholerae O1 El Tor clinical strain from 2005 outbreak. The ultrastructure and content of OMVs were investigated via the Scanning Elec- tron Microscopy (SEM) and SDS-PAGE analysis. Three doses of oral immunization were adjusted and total IgG and IgA in serum and intestinal secretion were measured by enzyme-linked immunosorbent assay (ELISA). Results: Extracted OMVs from the V. cholerae were spherical vesicles with a size ranging from 10 to 300 nm. OMV-im- munized mice showed an increased level of total IgG and IgA both in serum and intestinal secretion when compared to the negative controls. Also, there existed a higher level of secretory IgA than the total IgG, suggesting the most of protection against V. cholerae colonization provided by sIgA. Conclusion: Our findings revealed that oral immunization with V. cholerae OMVs might induce a long-term immunity, es- pecially when administered in combination with KWC. This study tested the adjuvant activity of OMVs and may be useful in future nano vaccine research.

scholarly journals Integrative analysis of outer membrane vesicles proteomics and whole-cell transcriptome analysis of eravacycline induced Acinetobacter baumannii strains

2019 ◽  
Author(s):  
Dinesh Kumar Kesavan ◽  
Aparna Vasudevan ◽  
Liang Wu ◽  
Jianguo Chen ◽  
Zhaoliang Su ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Rna Sequencing ◽  
Ribosomal Proteins ◽  
Expression Profiles ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Clinical Strain ◽  
Whole Cell ◽  
Induction Of Resistance

Abstract Background Acinetobacter baumannii is a multidrug resistant (MDR) hazardous bacterium with very high antimicrobial resistance profiles. Outer membrane vesicles (OMVs) help directly and/or indirectly towards antibiotic resistance in these organisms. The present study aims to look on the proteomic profile of OMV as well as on the bacterial transcriptome upon exposure and induction with eravacycline, a new synthetic fluorocycline. RNA sequencing analysis of whole cell and LC–MS/MS proteomic profiling of OMV proteome abundance were done to identify the differential expression among the eravacycline-induced A. baumannii ATCC 19606 and A. baumannii clinical strain JU0126.Results The Differential expressed genes from the RNA sequencing and were analysed using R package and bioinformatics software and tools. Genes encoding drug efflux and membrane transport were upregulated among the DEGs from both ATCC 19606 and JU0126 strains. As evident with the induction of eravacycline resistance, ribosomal proteins were upregulated in both the strains in the transcriptome profiles and also resistance pumps, such as MFS, RND, MATE and ABC transporters. High expression of stress and survival proteins were predominant in the OMVs proteome with ribosomal proteins, chaperons, OMPs OmpA, Omp38 upregulated in ATCC 19606 strain and ribosomal proteins, toluene tolerance protein, siderophore receptor and peptidases in the JU0126 strain. The induction of resistance to eravacycline was supported by the presence of upregulation of ribosomal proteins, resistance conferring factors and stress proteins in both the strains of A. baumannii ATCC 19606 and JU0126, with the whole-cell gene transcriptome towards both resistance and stress genes while the OMVs proteome enriched more with survival proteins.Conclusion The induction of resistance to eravacycline in the strains were evident with the increased expression of ribosomal and transcription related genes/proteins. Apart from this resistance conferring efflux pumps, outer membrane proteins and stress related proteins were also an essential part of the upregulated DEGs. However, the expression profiles of OMVs proteome in the study was independent with respect to the whole cell RNA expression profiles with low to no correlation. This indicates the possible role of OMVs to be more of back-up additional protection to the existing bacterial cell defence during the antibacterial stress.

scholarly journals Integrative analysis of outer membrane vesicles proteomics and whole-cell transcriptome analysis of eravacycline induced Acinetobacter baumannii strains

2020 ◽  
Author(s):  
Dinesh Kumar Kesavan ◽  
Aparna Vasudevan ◽  
Liang Wu ◽  
Jianguo Chen ◽  
Zhaoliang Su ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Rna Sequencing ◽  
Ribosomal Proteins ◽  
Expression Profiles ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Clinical Strain ◽  
Whole Cell ◽  
Induction Of Resistance

Abstract Background Acinetobacter baumannii is a multidrug resistant (MDR) hazardous bacterium with very high antimicrobial resistance profiles. Outer membrane vesicles (OMVs) help directly and/or indirectly towards antibiotic resistance in these organisms. The present study aims to look on the proteomic profile of OMV as well as on the bacterial transcriptome upon exposure and induction with eravacycline, a new synthetic fluorocycline. RNA sequencing analysis of whole cell and LC–MS/MS proteomic profiling of OMV proteome abundance were done to identify the differential expression among the eravacycline-induced A. baumannii ATCC 19606 and A. baumannii clinical strain JU0126.Results The Differential expressed genes from the RNA sequencing and were analysed using R package and bioinformatics software and tools. Genes encoding drug efflux and membrane transport were upregulated among the DEGs from both ATCC 19606 and JU0126 strains. As evident with the induction of eravacycline resistance, ribosomal proteins were upregulated in both the strains in the transcriptome profiles and also resistance pumps, such as MFS, RND, MATE and ABC transporters. High expression of stress and survival proteins were predominant in the OMVs proteome with ribosomal proteins, chaperons, OMPs OmpA, Omp38 upregulated in ATCC 19606 strain and ribosomal proteins, toluene tolerance protein, siderophore receptor and peptidases in the JU0126 strain. The induction of resistance to eravacycline was supported by the presence of upregulation of ribosomal proteins, resistance conferring factors and stress proteins in both the strains of A. baumannii ATCC 19606 and JU0126, with the whole-cell gene transcriptome towards both resistance and stress genes while the OMVs proteome enriched more with survival proteins.Conclusion The induction of resistance to eravacycline in the strains were evident with the increased expression of ribosomal and transcription related genes/proteins. Apart from this resistance conferring efflux pumps, outer membrane proteins and stress related proteins were also an essential part of the upregulated DEGs. However, the expression profiles of OMVs proteome in the study was independent with respect to the whole cell RNA expression profiles with low to no correlation. This indicates the possible role of OMVs to be more of back-up additional protection to the existing bacterial cell defence during the antibacterial stress.

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.

scholarly journals The Mutation of Conservative Asp268 Residue in the Peptidoglycan-Associated Domain of the OmpA Protein Affects Multiple Acinetobacter baumannii Virulence Characteristics

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1972 ◽  
Author(s):  
Jūratė Skerniškytė ◽  
Emilija Karazijaitė ◽  
Julien Deschamps ◽  
Renatas Krasauskas ◽  
Romain Briandet ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Protein A ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Clinical Strain ◽  
Infection Model ◽  
Terminal Domain ◽  
Ompa Protein

Acinetobacter baumannii is a nosocomial human pathogen of increasing concern due to its multidrug resistance profile. The outer membrane protein A (OmpA) is an abundant bacterial cell surface component involved in A. baumannii pathogenesis. It has been shown that the C-terminal domain of OmpA is located in the periplasm and non-covalently associates with the peptidoglycan layer via two conserved amino acids, thereby anchoring OmpA to the cell wall. Here, we investigated the role of one of the respective residues, D268 in OmpA of A. baumannii clinical strain Ab169, on its virulence characteristics by complementing the ΔompA mutant with the plasmid-borne ompAD268A allele. We show that while restoring the impaired biofilm formation of the ΔompA strain, the Ab169ompAD268A mutant tended to form bacterial filaments, indicating the abnormalities in cell division. Moreover, the Ab169 OmpA D268-mediated association to peptidoglycan was required for the manifestation of twitching motility, desiccation resistance, serum-induced killing, adhesion to epithelial cells and virulence in a nematode infection model, although it was dispensable for the uptake of β-lactam antibiotics by outer membrane vesicles. Overall, the results of this study demonstrate that the OmpA C-terminal domain-mediated association to peptidoglycan is critical for a number of virulent properties displayed by A. baumannii outside and within the host.

scholarly journals Protective Passive Immunity in Escherichia coli ETEC-Challenged Neonatal Mice Conferred by Orally Immunized Dams with Nanoparticles Containing Homologous Outer Membrane Vesicles

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 286
Author(s):  
Jose Matías ◽  
Yadira Pastor ◽  
Juan M. Irache ◽  
Carlos Gamazo
Keyword(s):  
Escherichia Coli ◽  
Single Dose ◽  
Outer Membrane ◽  
Passive Immunization ◽  
Membrane Vesicles ◽  
Oral Immunization ◽  
Outer Membrane Vesicles ◽  
Enterotoxigenic Escherichia Coli ◽  
Human Beings ◽  
Polymer Conjugate

Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of illness and death in mammals, including neonatal, recently weaned pigs and infant human beings. We have previously shown that outer membrane vesicles (OMV) obtained from ETEC serotypes encapsulated into zein nanoparticles, coated with a Gantrez-mannosamine polymer conjugate (OMV-NP), were immunogenic in mice and sows. In the present study, we show that pups from vaccinated mice were protected against ETEC F4 serotype challenge through maternal passive immunization. OMV from F4 cultures were collected and characterized. Two-week-pregnant BALB/c mice were orally immunized with a single dose of vesicles (0.2 mg) either free (OMV) or encapsulated into nanoparticles (OMV-NP). Evaluation of the antibodies in serum (IgG1, Ig2a or IgA) and feces (IgA) of dams immunized with OMV-NP revealed an enhancement of specific immunogenicity. The antibody response conferred by the nanoparticle adjuvant was also correlated with IL-6 and IL-10 splenic levels. Each mother was allowed to feed her progeny for one week. Suckling pups presented specific IgA in feces demonstrating their passive immunization through colostrum intake. Two weeks after the pups were born, they were infected orally with a single dose of F4 E. coli (1.2 × 108 CFU/pup). Results showed that 70% of the pups from dams immunized with OMV-NP were protected. In contrast, 80% of the pups from dams immunized with free OMV died as a result of the experimental challenge. These findings support the use of zein nanoparticles coated with a Gantrez-mannosamine shield as adjuvant delivery system for the oral immunization during pregnancy to confer immunity to the offspring through maternal immunization

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 Immunization of Mice With Vibrio cholerae Outer-Membrane Vesicles Protects Against Hyperinfectious Challenge and Blocks Transmission

2011 ◽  
Vol 205 (3) ◽  
pp. 412-421 ◽  
Author(s):  
Anne L. Bishop ◽  
Abdullah A. Tarique ◽  
Bharathi Patimalla ◽  
Stephen B. Calderwood ◽  
Firdausi Qadri ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles

scholarly journals Immunization with Vibrio cholerae Outer Membrane Vesicles Induces Protective Immunity in Mice

2008 ◽  
Vol 76 (10) ◽  
pp. 4554-4563 ◽  
Author(s):  
Stefan Schild ◽  
Eric J. Nelson ◽  
Andrew Camilli
Keyword(s):  
Immune Responses ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
High Titer ◽  
Immunoglobulin A ◽  
Membrane Vesicles ◽  
Oral Route ◽  
Outer Membrane Vesicles ◽  
Intranasal Route ◽  
Female Mice

ABSTRACT The gram-negative bacterium Vibrio cholerae releases outer membrane vesicles (OMVs) during growth. In this study, we immunized female mice by the intranasal, intragastric, or intraperitoneal route with purified OMVs derived from V. cholerae. Independent of the route of immunization, mice induced specific, high-titer immune responses of similar levels against a variety of antigens present in the OMVs. After the last immunization, the half-maximum total immunoglobulin titer was stable over a 3-month period, indicating that the immune response was long lasting. The induction of specific isotypes, however, was dependent on the immunization route. Immunoglobulin A, for example, was induced to a significant level only by mucosal immunization, with the intranasal route generating the highest titers. We challenged the offspring of immunized female mice with V. cholerae via the oral route in two consecutive periods, approximately 30 and 95 days after the last immunization. Regardless of the route of immunization, the offspring was protected against colonization with V. cholerae in both challenge periods. Our results show that mucosal immunizations via both routes with OMVs derived from V. cholerae induce long-term protective immune responses against this gastrointestinal pathogen. These findings may contribute to the development of “nonliving,” OMV-based vaccines against V. cholerae and other enteric pathogens, using the oral or intranasal route of immunization.

scholarly journals A combined vaccine approach against Vibrio cholerae and ETEC based on outer membrane vesicles

2015 ◽  
Vol 6 ◽  
Author(s):  
Deborah R. Leitner ◽  
Sabine Lichtenegger ◽  
Philipp Temel ◽  
Franz G. Zingl ◽  
Desiree Ratzberger ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Vaccine Approach ◽  
Combined Vaccine
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