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Fantoni G, Boccadifuoco G, Verdirosa F, Molesti E, Manenti A, Montomoli E. Current challenges and improvements in assessing the immunogenicity of bacterial vaccines. Front Microbiol 2024; 15:1404637. [PMID: 39044946 PMCID: PMC11263209 DOI: 10.3389/fmicb.2024.1404637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Accepted: 06/26/2024] [Indexed: 07/25/2024] Open
Abstract
The increase in antimicrobial-resistant bacterial strains has highlighted the need for a new vaccine strategy. The primary goal of a candidate vaccine is to prevent disease, by inducing a persistent immunologic memory, through the activation of pathogen-specific immune response. Antibody titer is the main parameter used to assess the immunogenicity of bacterial vaccine candidates and it is the most widely used as a correlate of protection. On the other hand, the antibody titer alone cannot provide complete information on all the activity mediated by antibodies which can only be assessed by functional assays, like the serum bactericidal assay and the opsonophagocytosis assay. However, due to the involvement of many biological factors, these assays are difficult to standardize. Some improvements have been achieved in recent years, but further optimizations are needed to minimize inter- and intra-laboratories variability and to allow the applicability of these functional assays for the vaccine immunogenicity assessment on a larger scale.
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Affiliation(s)
- Giulia Fantoni
- VisMederi S.r.l., Siena, Italy
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | | | | | | | | | - Emanuele Montomoli
- VisMederi S.r.l., Siena, Italy
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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2
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Conti V, Rossi O, Clarkson KA, Mancini F, Nakakana UN, Sarakinou E, Callegaro A, Ferruzzi P, Acquaviva A, Arora AK, Marchetti E, Necchi F, Frenck RW, Martin LB, Kaminski RW, Podda A, Micoli F. Putative correlates of protection against shigellosis assessing immunomarkers across responses to S. sonnei investigational vaccine. NPJ Vaccines 2024; 9:56. [PMID: 38459072 PMCID: PMC10923941 DOI: 10.1038/s41541-024-00822-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 01/30/2024] [Indexed: 03/10/2024] Open
Abstract
Shigella spp. are a leading bacterial cause of diarrhea. No widely licensed vaccines are available and there is no generally accepted correlate of protection. We tested a S. sonnei Generalized Modules for Membrane Antigen (GMMA)-based vaccine (1790GAHB) in a phase 2b, placebo-controlled, randomized, controlled human infection model study (NCT03527173) enrolling healthy United States adults aged 18-50 years. We report analyses evaluating immune responses to vaccination, with the aim to identify correlates of risk for shigellosis among assessed immunomarkers. We found that 1790GAHB elicited S. sonnei lipopolysaccharide specific α4β7+ immunoglobulin (Ig) G and IgA secreting B cells which are likely homing to the gut, indicating the ability to induce a mucosal in addition to a systemic response, despite parenteral delivery. We were unable to establish or confirm threshold levels that predict vaccine efficacy facilitating the evaluation of vaccine candidates. However, serum anti-lipopolysaccharide IgG and bactericidal activity were identified as potential correlates of risk for shigellosis.
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Affiliation(s)
| | - Omar Rossi
- GSK Vaccines Institute for Global Health, Siena, Italy
| | - Kristen A Clarkson
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
- Horizon Therapeutics, Deerfield, IL, USA
| | | | | | | | | | | | | | | | | | | | - Robert W Frenck
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Laura B Martin
- GSK Vaccines Institute for Global Health, Siena, Italy
- US Pharmacopeial Convention, Rockville, MD, USA
| | - Robert W Kaminski
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
- Latham BioPharm Group, Cambridge, MA, USA
| | - Audino Podda
- GSK Vaccines Institute for Global Health, Siena, Italy
- Independent Consultant, Siena, Italy
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3
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Gasperini G, Massai L, De Simone D, Raso MM, Palmieri E, Alfini R, Rossi O, Ravenscroft N, Kuttel MM, Micoli F. O-Antigen decorations in Salmonella enterica play a key role in eliciting functional immune responses against heterologous serovars in animal models. Front Cell Infect Microbiol 2024; 14:1347813. [PMID: 38487353 PMCID: PMC10937413 DOI: 10.3389/fcimb.2024.1347813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/15/2024] [Indexed: 03/17/2024] Open
Abstract
Introduction Different serovars of Salmonella enterica cause systemic diseases in humans including enteric fever, caused by S. Typhi and S. Paratyphi A, and invasive nontyphoidal salmonellosis (iNTS), caused mainly by S. Typhimurium and S. Enteritidis. No vaccines are yet available against paratyphoid fever and iNTS but different strategies, based on the immunodominant O-Antigen component of the lipopolysaccharide, are currently being tested. The O-Antigens of S. enterica serovars share structural features including the backbone comprising mannose, rhamnose and galactose as well as further modifications such as O-acetylation and glucosylation. The importance of these O-Antigen decorations for the induced immunogenicity and cross-reactivity has been poorly characterized. Methods These immunological aspects were investigated in this study using Generalized Modules for Membrane Antigens (GMMA) as delivery systems for the different O-Antigen variants. This platform allowed the rapid generation and in vivo testing of defined and controlled polysaccharide structures through genetic manipulation of the O-Antigen biosynthetic genes. Results Results from mice and rabbit immunization experiments highlighted the important role played by secondary O-Antigen decorations in the induced immunogenicity. Moreover, molecular modeling of O-Antigen conformations corroborated the likelihood of cross-protection between S. enterica serovars. Discussion Such results, if confirmed in humans, could have a great impact on the design of a simplified vaccine composition able to maximize functional immune responses against clinically relevant Salmonella enterica serovars.
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Affiliation(s)
| | - Luisa Massai
- GSK Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | | | - Elena Palmieri
- GSK Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Renzo Alfini
- GSK Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Omar Rossi
- GSK Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Neil Ravenscroft
- Department of Chemistry, University of Cape Town, Rondebosch, South Africa
| | - Michelle M. Kuttel
- Department of Computer Science, University of Cape Town, Rondebosch, South Africa
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Lei EK, Azmat A, Henry KA, Hussack G. Outer membrane vesicles as a platform for the discovery of antibodies to bacterial pathogens. Appl Microbiol Biotechnol 2024; 108:232. [PMID: 38396192 PMCID: PMC10891261 DOI: 10.1007/s00253-024-13033-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
Bacterial outer membrane vesicles (OMVs) are nanosized spheroidal particles shed by gram-negative bacteria that contain biomolecules derived from the periplasmic space, the bacterial outer membrane, and possibly other compartments. OMVs can be purified from bacterial culture supernatants, and by genetically manipulating the bacterial cells that produce them, they can be engineered to harbor cargoes and/or display molecules of interest on their surfaces including antigens that are immunogenic in mammals. Since OMV bilayer-embedded components presumably maintain their native structures, OMVs may represent highly useful tools for generating antibodies to bacterial outer membrane targets. OMVs have historically been utilized as vaccines or vaccine constituents. Antibodies that target bacterial surfaces are increasingly being explored as antimicrobial agents either in unmodified form or as targeting moieties for bactericidal compounds. Here, we review the properties of OMVs, their use as immunogens, and their ability to elicit antibody responses against bacterial antigens. We highlight antigens from bacterial pathogens that have been successfully targeted using antibodies derived from OMV-based immunization and describe opportunities and limitations for OMVs as a platform for antimicrobial antibody development. KEY POINTS: • Outer membrane vesicles (OMVs) of gram-negative bacteria bear cell-surface molecules • OMV immunization allows rapid antibody (Ab) isolation to bacterial membrane targets • Review and analysis of OMV-based immunogens for antimicrobial Ab development.
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Affiliation(s)
- Eric K Lei
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
| | - Aruba Azmat
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
| | - Kevin A Henry
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Greg Hussack
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada.
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Tondi S, Siena E, Essaghir A, Bozzetti B, Bechtold V, Scaillet A, Clemente B, Marrocco M, Sammicheli C, Tavarini S, Micoli F, Oldrini D, Pezzicoli A, Di Fede M, Brazzoli M, Ulivieri C, Schiavetti F. Molecular Signature of Monocytes Shaped by the Shigella sonnei 1790-Generalized Modules for Membrane Antigens Vaccine. Int J Mol Sci 2024; 25:1116. [PMID: 38256189 PMCID: PMC10816432 DOI: 10.3390/ijms25021116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/13/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
Shigellosis, an acute gastroenteritis infection caused by Shigella species, remains a public health burden in developing countries. Recently, many outbreaks due to Shigella sonnei multidrug-resistant strains have been reported in high-income countries, and the lack of an effective vaccine represents a major hurdle to counteract this bacterial pathogen. Vaccine candidates against Shigella sonnei are under clinical development, including a Generalized Modules for Membrane Antigens (GMMA)-based vaccine. The mechanisms by which GMMA-based vaccines interact and activate human immune cells remain elusive. Our previous study provided the first evidence that both adaptive and innate immune cells are targeted and functionally shaped by the GMMA-based vaccine. Here, flow cytometry and confocal microscopy analysis allowed us to identify monocytes as the main target population interacting with the S. sonnei 1790-GMMA vaccine on human peripheral blood. In addition, transcriptomic analysis of this cell population revealed a molecular signature induced by 1790-GMMA mostly correlated with the inflammatory response and cytokine-induced processes. This also impacts the expression of genes associated with macrophages' differentiation and T cell regulation, suggesting a dual function for this vaccine platform both as an antigen carrier and as a regulator of immune cell activation and differentiation.
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Affiliation(s)
- Serena Tondi
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Emilio Siena
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Ahmed Essaghir
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Benoît Bozzetti
- Preclinical Research & Development, GSK, 1330 Rixensart, Belgium
| | - Viviane Bechtold
- Preclinical Research & Development, GSK, 1330 Rixensart, Belgium
| | - Aline Scaillet
- Preclinical Research & Development, GSK, 1330 Rixensart, Belgium
| | - Bruna Clemente
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Mariateresa Marrocco
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | | | - Simona Tavarini
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Francesca Micoli
- GSK Vaccines Institute for Global Health S.R.L. (GVGH), 53100 Siena, Italy
| | - Davide Oldrini
- GSK Vaccines Institute for Global Health S.R.L. (GVGH), 53100 Siena, Italy
| | | | - Martina Di Fede
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Michela Brazzoli
- Preclinical Research & Development, GSK, 53100 Siena, Italy; (S.T.)
| | - Cristina Ulivieri
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
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Boudier A, Le Faou A. Nanoparticles and Other Nanostructures and the Control of Pathogens: From Bench to Vaccines. Int J Mol Sci 2023; 24:ijms24109063. [PMID: 37240409 DOI: 10.3390/ijms24109063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Parasites and microorganisms (protozoa, bacteria, and viruses) are still a concern despite progress in hygiene and anti-infectious therapy [...].
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Affiliation(s)
- Ariane Boudier
- Faculty of Pharmacy, Université de Lorraine, F-54000 Nancy, France
| | - Alain Le Faou
- Faculty of Pharmacy, Université de Lorraine, F-54000 Nancy, France
- Faculty of Medicine, Maieutic and Health Sciences, University of Lorraine, Pole Brabois Santé, F-54000 Nancy, France
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Boero E, Vezzani G, Micoli F, Pizza M, Rossi O. Functional assays to evaluate antibody-mediated responses against Shigella: a review. Front Cell Infect Microbiol 2023; 13:1171213. [PMID: 37260708 PMCID: PMC10227456 DOI: 10.3389/fcimb.2023.1171213] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/27/2023] [Indexed: 06/02/2023] Open
Abstract
Shigella is a major global pathogen and the etiological agent of shigellosis, a diarrheal disease that primarily affects low- and middle-income countries. Shigellosis is characterized by a complex, multistep pathogenesis during which bacteria use multiple invasion proteins to manipulate and invade the intestinal epithelium. Antibodies, especially against the O-antigen and some invasion proteins, play a protective role as titres against specific antigens inversely correlate with disease severity; however, the context of antibody action during pathogenesis remains to be elucidated, especially with Shigella being mostly an intracellular pathogen. In the absence of a correlate of protection, functional assays rebuilding salient moments of Shigella pathogenesis can improve our understanding of the role of protective antibodies in blocking infection and disease. In vitro assays are important tools to build correlates of protection. Only recently animal models to recapitulate human pathogenesis, often not in full, have been established. This review aims to discuss in vitro assays to evaluate the functionality of anti-Shigella antibodies in polyclonal sera in light of the multistep and multifaced Shigella infection process. Indeed, measurement of antibody level alone may limit the evaluation of full vaccine potential. Serum bactericidal assay (SBA), and other functional assays such as opsonophagocytic killing assays (OPKA), and adhesion/invasion inhibition assays (AIA), are instead physiologically relevant and may provide important information regarding the role played by these effector mechanisms in protective immunity. Ultimately, the review aims at providing scientists in the field with new points of view regarding the significance of functional assays of choice which may be more representative of immune-mediated protection mechanisms.
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Affiliation(s)
- Elena Boero
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., Siena, Italy
| | - Giacomo Vezzani
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., Siena, Italy
| | - Francesca Micoli
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., Siena, Italy
| | - Mariagrazia Pizza
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., Siena, Italy
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Omar Rossi
- GSK Vaccines Institute for Global Health (GVGH) S.r.l., Siena, Italy
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