Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development

The attractiveness of OMVs derived from Gram-negative bacteria lies in the fact that they have two biomembranes sandwiching a peptidoglycan layer. It is well known that the envelope of OMVs consists of the outer bacterial membrane [OM] and not of the inner one [IM] of the source bacterium. This impl...

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Main Authors: Branko Velimirov, Branko Alexander Velimirov
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Life
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Online Access:https://www.mdpi.com/2075-1729/14/12/1584
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author Branko Velimirov
Branko Alexander Velimirov
author_facet Branko Velimirov
Branko Alexander Velimirov
author_sort Branko Velimirov
collection DOAJ
description The attractiveness of OMVs derived from Gram-negative bacteria lies in the fact that they have two biomembranes sandwiching a peptidoglycan layer. It is well known that the envelope of OMVs consists of the outer bacterial membrane [OM] and not of the inner one [IM] of the source bacterium. This implies that all outer membranous molecules found in the OM act as antigens. However, under specific conditions, some of the inner membrane proteins can be exported into the outer membrane layer and perform as antigens. A key information was that the used purification procedures for OMVs, the induction methods to increase the production of OMVs as well as the specific mutant strains obtained via genetic engineering affect the composition of potential antigens on the surface and in the lumen of the OMVs. The available literature allowed us to list the major antigens that could be defined on OMVs. The functions of the antigens within the source bacterium are discussed for a better understanding of the various available hypotheses on the biogenesis of vesicle formation. Also, the impacts of OMV antigens on the immune system using animal models are assessed. Furthermore, information on the pathways of OMVs entering the host cell is presented. An example of a bacterial infection that causes epidemic diseases, namely via <i>Neisseria meningitidis</i>, is used to demonstrate that OMVs derived from this pathogen elicit protective immune responses when administered as a vaccine. Furthermore, information on OMV vaccines under development is presented. The assembled knowledge allowed us to formulate a number of reasons why OMVs are attractive as vaccine platforms, as their undesirable side effects remain small, and to provide an outlook on the potential use of OMVs as a vaccine platform.
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spelling doaj-art-d442694fe2d942fbab1f64f67aa2e07e2025-08-20T02:57:14ZengMDPI AGLife2075-17292024-12-011412158410.3390/life14121584Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine DevelopmentBranko Velimirov0Branko Alexander Velimirov1Division of Microbiology and Molecular Biology, Medical Faculty, Private Sigmund Freud University, Freudplatz 3, 1020 Wien, AustriaDivision of Microbiology and Molecular Biology, Medical Faculty, Private Sigmund Freud University, Freudplatz 3, 1020 Wien, AustriaThe attractiveness of OMVs derived from Gram-negative bacteria lies in the fact that they have two biomembranes sandwiching a peptidoglycan layer. It is well known that the envelope of OMVs consists of the outer bacterial membrane [OM] and not of the inner one [IM] of the source bacterium. This implies that all outer membranous molecules found in the OM act as antigens. However, under specific conditions, some of the inner membrane proteins can be exported into the outer membrane layer and perform as antigens. A key information was that the used purification procedures for OMVs, the induction methods to increase the production of OMVs as well as the specific mutant strains obtained via genetic engineering affect the composition of potential antigens on the surface and in the lumen of the OMVs. The available literature allowed us to list the major antigens that could be defined on OMVs. The functions of the antigens within the source bacterium are discussed for a better understanding of the various available hypotheses on the biogenesis of vesicle formation. Also, the impacts of OMV antigens on the immune system using animal models are assessed. Furthermore, information on the pathways of OMVs entering the host cell is presented. An example of a bacterial infection that causes epidemic diseases, namely via <i>Neisseria meningitidis</i>, is used to demonstrate that OMVs derived from this pathogen elicit protective immune responses when administered as a vaccine. Furthermore, information on OMV vaccines under development is presented. The assembled knowledge allowed us to formulate a number of reasons why OMVs are attractive as vaccine platforms, as their undesirable side effects remain small, and to provide an outlook on the potential use of OMVs as a vaccine platform.https://www.mdpi.com/2075-1729/14/12/1584bacterial antigensouter membranesimmune responseToll-like receptorsantimicrobial peptidesvaccine platform
spellingShingle Branko Velimirov
Branko Alexander Velimirov
Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
Life
bacterial antigens
outer membranes
immune response
Toll-like receptors
antimicrobial peptides
vaccine platform
title Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
title_full Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
title_fullStr Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
title_full_unstemmed Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
title_short Immune Responses Elicited by Outer Membrane Vesicles of Gram-Negative Bacteria: Important Players in Vaccine Development
title_sort immune responses elicited by outer membrane vesicles of gram negative bacteria important players in vaccine development
topic bacterial antigens
outer membranes
immune response
Toll-like receptors
antimicrobial peptides
vaccine platform
url https://www.mdpi.com/2075-1729/14/12/1584
work_keys_str_mv AT brankovelimirov immuneresponseselicitedbyoutermembranevesiclesofgramnegativebacteriaimportantplayersinvaccinedevelopment
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