scholarly journals Outer Membrane Vesicle Induction and Isolation for Vaccine Development

2021 ◽  
Vol 12 ◽  
Author(s):  
Melanie D. Balhuizen ◽  
Edwin J. A. Veldhuizen ◽  
Henk P. Haagsman

Gram-negative bacteria release vesicular structures from their outer membrane, so called outer membrane vesicles (OMVs). OMVs have a variety of functions such as waste disposal, communication, and antigen or toxin delivery. These vesicles are the promising structures for vaccine development since OMVs carry many surface antigens that are identical to the bacterial surface. However, isolation is often difficult and results in low yields. Several methods to enhance OMV yield exist, but these do affect the resulting OMVs. In this review, our current knowledge about OMVs will be presented. Different methods to induce OMVs will be reviewed and their advantages and disadvantages will be discussed. The effects of the induction and isolation methods used in several immunological studies on OMVs will be compared. Finally, the challenges for OMV-based vaccine development will be examined and one example of a successful OMV-based vaccine will be presented.

2019 ◽  
Vol 5 (4) ◽  
pp. 184-198 ◽  
Author(s):  
Guangchao Qing ◽  
Ningqiang Gong ◽  
Xiaohui Chen ◽  
Jing Chen ◽  
Hong Zhang ◽  
...  

Abstract Bacterial outer membrane vesicle (OMV) is a kind of spherical lipid bilayer nanostructure naturally secreted by bacteria, which has diverse functions such as intracellular and extracellular communication, horizontal gene transfer, transfer of contents to host cells, and eliciting an immune response in host cells. In this review, several methods including ultracentrifugation and precipitation for isolating OMVs were summarized. The latest progresses of OMVs in biomedical fields, especially in vaccine development, cancer treatment, infection control, and bioimaging and detection were also summarized in this review. We highlighted the importance of genetic engineering for the safe and effective application and in facilitating the rapid development of OMVs. Finally, we discussed the bottleneck problems about OMVs in preparation and application at present and put forward our own suggestions about them. Some perspectives of OMVs in biomedical field were also provided.


mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Joachim Reidl

ABSTRACT Recent research has focused on the biological role of outer membrane vesicles (OMVs), which are derived from the outer membranes (OMs) of Gram-negative bacteria, and their potential exploitation as therapeutics. OMVs have been characterized in many ways and functions. Until recently, research focused on hypothetical and empirical models that addressed the molecular mechanisms of OMV biogenesis, such as vesicles bulging from the OM in various ways. The recently reported study by Elhenawy et al. (mBio 7:e00940-16, 2016, http://dx.doi.org/10.1128/mBio.00940-16 ) provided further insights into OMV biogenesis of Salmonella enterica serovar Typhimurium. That study showed that deacylation of lipopolysaccharides (LPS) influences the level of OMV production and, furthermore, determines a sorting of high versus low acylated LPS in OMs and OMVs, respectively. Interestingly, deacylation may inversely correlate with other LPS modifications, suggesting some synergy toward optimized host resistance via best OM compositions for S . Typhimurium.


2021 ◽  
Vol 12 ◽  
Author(s):  
Shelby L. Reimer ◽  
Daniel R. Beniac ◽  
Shannon L. Hiebert ◽  
Timothy F. Booth ◽  
Patrick M. Chong ◽  
...  

Outer membrane vesicles (OMVs) produced by Gram-negative bacteria are mediators of cell survival and pathogenesis by facilitating virulence factor dissemination and resistance to antimicrobials. Studies of OMV properties often focus on hypervesiculating Escherichia coli mutants that have increased OMV production when compared to their corresponding wild-type (WT) strains. Currently, two conventional techniques, ultracentrifugation (UC) and ultradiafiltration (UF), are used interchangeably to isolate OMVs, however, there is concern that each technique may inadvertently alter the properties of isolated OMVs during study. To address this concern, we compared two OMV isolation methods, UC and UF, with respect to final OMV quantities, size distributions, and morphologies using a hypervesiculating Escherichia coli K-12 ΔtolA mutant. Nanoparticle tracking analysis (NTA) indicated that UC techniques result in lower vesicle yields compared to UF. However, UF permitted isolation of OMVs with smaller average sizes than UC, highlighting a potential OMV isolation size bias by each technique. Cryo-transmission electron microscopy (cryo-TEM) visualization of isolated OMVs revealed distinct morphological differences between WT and ΔtolA OMVs, where ΔtolA OMVs isolated by either UC or UF method possessed a greater proportion of OMVs with two or more membranes. Proteomic OMV analysis of WT and ΔtolA OMVs confirmed that ΔtolA enhances inner plasma membrane carryover in multi-lamellar OMVs. This study demonstrates that UC and UF are useful techniques for OMV isolation, where UF may be preferable due to faster isolation, higher OMV yields and enrichment of smaller sized vesicles.


2019 ◽  
Author(s):  
Jiajun Wang ◽  
Rémi Terrasse ◽  
Jayesh Arun Bafna ◽  
Lorraine Benier ◽  
Mathias Winterhalter

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from <i>Escherichia coli</i>, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (<i>k<sub>on</sub></i>) and lower dissociation (<i>k<sub>off</sub></i>) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1661
Author(s):  
Mei-Hsiu Chen ◽  
Tse-Ying Liu ◽  
Yu-Chiao Chen ◽  
Ming-Hong Chen

Glioblastoma, formerly known as glioblastoma multiforme (GBM), is refractory to existing adjuvant chemotherapy and radiotherapy. We successfully synthesized a complex, Au–OMV, with two specific nanoparticles: gold nanoparticles (AuNPs) and outer-membrane vesicles (OMVs) from E. coli. Au–OMV, when combined with radiotherapy, produced radiosensitizing and immuno-modulatory effects that successfully suppressed tumor growth in both subcutaneous G261 tumor-bearing and in situ (brain) tumor-bearing C57BL/6 mice. Longer survival was also noted with in situ tumor-bearing mice treated with Au–OMV and radiotherapy. The mechanisms for the successful treatment were evaluated. Intracellular reactive oxygen species (ROS) greatly increased in response to Au–OMV in combination with radiotherapy in G261 glioma cells. Furthermore, with a co-culture of G261 glioma cells and RAW 264.7 macrophages, we found that GL261 cell viability was related to chemotaxis of macrophages and TNF-α production.


2018 ◽  
Vol 115 (41) ◽  
pp. 10428-10433 ◽  
Author(s):  
Francesca Micoli ◽  
Simona Rondini ◽  
Renzo Alfini ◽  
Luisa Lanzilao ◽  
Francesca Necchi ◽  
...  

Nontyphoidal Salmonellae cause a devastating burden of invasive disease in sub-Saharan Africa with high levels of antimicrobial resistance. Vaccination has potential for a major global health impact, but no licensed vaccine is available. The lack of commercial incentive makes simple, affordable technologies the preferred route for vaccine development. Here we compare equivalent Generalized Modules for Membrane Antigens (GMMA) outer membrane vesicles and O-antigen-CRM197 glycoconjugates to deliver lipopolysaccharide O-antigen in bivalent Salmonella Typhimurium and Enteritidis vaccines. Salmonella strains were chosen and tolR deleted to induce GMMA production. O-antigens were extracted from wild-type bacteria and conjugated to CRM197. Purified GMMA and glycoconjugates were characterized and tested in mice for immunogenicity and ability to reduce Salmonella infection. GMMA and glycoconjugate O-antigen had similar structural characteristics, O-acetylation, and glucosylation levels. Immunization with GMMA induced higher anti–O-antigen IgG than glycoconjugate administered without Alhydrogel adjuvant. With Alhydrogel, antibody levels were similar. GMMA induced a diverse antibody isotype profile with greater serum bactericidal activity than glycoconjugate, which induced almost exclusively IgG1. Immunization reduced bacterial colonization of mice subsequently infected with Salmonella. S. Typhimurium numbers were lower in tissues of mice vaccinated with GMMA compared with glycoconjugate. S. Enteritidis burden in the tissues was similar in mice immunized with either vaccine. With favorable immunogenicity, low cost, and ability to induce functional antibodies and reduce bacterial burden, GMMA offer a promising strategy for the development of a nontyphoidal Salmonella vaccine compared with established glycoconjugates. GMMA technology is potentially attractive for development of vaccines against other bacteria of global health significance.


2011 ◽  
Vol 18 (5) ◽  
pp. 736-742 ◽  
Author(s):  
Oliver Koeberling ◽  
Isabel Delany ◽  
Dan M. Granoff

ABSTRACTNative outer membrane vesicles (NOMV) (not detergent treated), which are prepared from recombinant strains with attenuated endotoxin activity and overexpressed factor H binding protein (fHbp), elicited broad serum bactericidal antibody responses in mice. The amount of overexpressed fHbp required for optimal immunogenicity is not known. In this study we prepared NOMV vaccines from LpxL1 knockout (ΔLpxL1) mutants with penta-acylated lipooligosaccharide and attenuated endotoxin activity. The recombinant strains had wild-type (1×) fHbp expression or were engineered for 3-fold- or 10-fold-increased fHbp expression (3× or 10× fHbp). Control vaccines included NOMV from ΔLpxL1/ΔfHbp mutants or recombinant fHbp. In mice, only the 10× fHbp NOMV vaccine elicited significantly higher serum IgG anti-fHbp antibody titers than the corresponding 1× fHbp NOMV or recombinant fHbp vaccine. The 10× fHbp NOMV vaccine also elicited higher bactericidal responses (P< 0.05) against five group B strains with heterologous PorA than the recombinant fHbp or 1× fHbp NOMV vaccine. The 3× fHbp NOMV vaccine gave higher bactericidal titers against only one strain. Serum bactericidal titers in mice immunized with the control ΔfHbp NOMV vaccines were <1:10, and bactericidal titers in mice immunized with the 10× fHbp NOMV vaccine were <1:10 after adsorption of anti-fHbp antibodies. Mixing antiserum to NOMV vaccines from fHbp knockout mutants with antiserum to recombinant fHbp did not increase anti-fHbp bactericidal titers. Thus, a critical threshold of increased fHbp expression is required for NOMV vaccines to elicit broad serum bactericidal responses, and the antibodies conferring protection are directed primarily at fHbp.


2014 ◽  
Vol 80 (18) ◽  
pp. 5854-5865 ◽  
Author(s):  
Maria H. Daleke-Schermerhorn ◽  
Tristan Felix ◽  
Zora Soprova ◽  
Corinne M. ten Hagen-Jongman ◽  
David Vikström ◽  
...  

ABSTRACTOuter membrane vesicles (OMVs) are spherical nanoparticles that naturally shed from Gram-negative bacteria. They are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. By packaging foreign polypeptides in OMVs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. Antigens exposed at the vesicle surface have been suggested to elicit protection superior to that from antigens concealed inside OMVs, but hitherto robust methods for targeting heterologous proteins to the OMV surface have been lacking. We have exploited our previously developed hemoglobin protease (Hbp) autotransporter platform for display of heterologous polypeptides at the OMV surface. One, two, or three of theMycobacterium tuberculosisantigens ESAT6, Ag85B, and Rv2660c were targeted to the surface ofEscherichia coliOMVs upon fusion to Hbp. Furthermore, a hypervesiculating ΔtolRΔtolAderivative of attenuatedSalmonella entericaserovar Typhimurium SL3261 was generated, enabling efficient release and purification of OMVs decorated with multiple heterologous antigens, exemplified by theM. tuberculosisantigens and epitopes fromChlamydia trachomatismajor outer membrane protein (MOMP). Also, we showed that delivery ofSalmonellaOMVs displaying Ag85B to antigen-presenting cellsin vitroresults in processing and presentation of an epitope that is functionally recognized by Ag85B-specific T cell hybridomas. In conclusion, the Hbp platform mediates efficient display of (multiple) heterologous antigens, individually or combined within one molecule, at the surface of OMVs. Detection of antigen-specific immune responses upon vesicle-mediated delivery demonstrated the potential of our system for vaccine development.


2019 ◽  
Vol 85 (19) ◽  
Author(s):  
Tanja Fischer ◽  
Martin Schorb ◽  
Greta Reintjes ◽  
Androniki Kolovou ◽  
Rachel Santarella-Mellwig ◽  
...  

ABSTRACT Large surface-to-volume ratios provide optimal nutrient uptake conditions for small microorganisms in oligotrophic habitats. The surface area can be increased with appendages. Here, we describe chains of interconnecting vesicles protruding from cells of strain Hel3_A1_48, affiliating with Formosa spp. within the Flavobacteriia and originating from coastal free-living bacterioplankton. The chains were up to 10 μm long and had vesicles emanating from the outer membrane with a single membrane and a size of 80 to 100 nm by 50 to 80 nm. Cells extruded membrane tubes in the exponential phase, whereas vesicle chains dominated on cells in the stationary growth phase. This formation is known as pearling, a physical morphogenic process in which membrane tubes protrude from liposomes and transform into chains of interconnected vesicles. Proteomes of whole-cell membranes and of detached vesicles were dominated by outer membrane proteins, including the type IX secretion system and surface-attached peptidases, glycoside hydrolases, and endonucleases. Fluorescein-labeled laminarin stained the cells and the vesicle chains. Thus, the appendages provide binding domains and degradative enzymes on their surfaces and probably storage volume in the vesicle lumen. Both may contribute to the high abundance of these Formosa-affiliated bacteria during laminarin utilization shortly after spring algal blooms. IMPORTANCE Microorganisms produce membrane vesicles. One synthesis pathway seems to be pearling that describes the physical formation of vesicle chains from phospholipid vesicles via extended tubes. Bacteria with vesicle chains had been observed as well as bacteria with tubes, but pearling was so far not observed. Here, we report the observation of, initially, tubes and then vesicle chains during the growth of a flavobacterium, suggesting biopearling of vesicle chains. The flavobacterium is abundant during spring bacterioplankton blooms developing after algal blooms and has a special set of enzymes for laminarin, the major storage polysaccharide of microalgae. We demonstrated with fluorescently labeled laminarin that the vesicle chains bind laminarin or contain laminarin-derived compounds. Proteomic analyses revealed surface-attached degradative enzymes on the outer membrane vesicles. We conclude that the large surface area and the lumen of vesicle chains may contribute to the ecological success of this marine bacterium.


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