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Desalegn G, Tamilselvi CS, Lemme-Dumit JM, Heine SJ, Dunn D, Ndungo E, Kapoor N, Oaks EV, Fairman J, Pasetti MF. Shigella virulence protein VirG is a broadly protective antigen and vaccine candidate. NPJ Vaccines 2024; 9:2. [PMID: 38167387 PMCID: PMC10761965 DOI: 10.1038/s41541-023-00797-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Diarrhea caused by Shigella has been associated with high morbidity and mortality in young children worldwide. There are no licensed vaccines, and those clinically advanced have restricted coverage as they elicit serotype-specific immunity while disease is caused by multiple circulating serotypes. Our group had previously reported a close association between serum antibodies to the Shigella virulence factor VirG (or IcsA) and clinical protection in infected individuals. VirG is highly conserved among Shigella strains and appealing as a broad-spectrum vaccine candidate. In this study, we investigated the immunogenicity and protective capacity of VirG as a subunit vaccine in mice. The surface-exposed alpha (α) domain of VirG (VirGα) was produced as a recombinant protein. This region has almost identical immune reactivity to full-length VirG. Administered intramuscularly with alum, VirGα elicited robust immune responses and high protective efficacy against S. flexneri 2a and S. sonnei. Almost complete protection was afforded by VirGα given intranasally with the E. coli double mutant heat-labile toxin (dmLT). VirGα-specific antibodies recognized VirG expressed on live Shigella, and blocked Shigella adhesion and invasion to human colonic cells. These results show for the first time that VirGα is a promising cross-protective vaccine candidate to prevent Shigella infection.
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Affiliation(s)
- Girmay Desalegn
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Chitradevi S Tamilselvi
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Jose M Lemme-Dumit
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Shannon J Heine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Dylan Dunn
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Esther Ndungo
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Neeraj Kapoor
- Vaxcyte, Inc., 825 Industrial Road, San Carlos, CA, 94070, USA
| | - Edwin V Oaks
- Patuxent Research and Consulting Group, 3106 Arrowhead Farm Rd, Gambrills, MD, 21054, USA
| | - Jeff Fairman
- Vaxcyte, Inc., 825 Industrial Road, San Carlos, CA, 94070, USA
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA.
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2
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Li S, Anvari S, Ptacek G, Upadhyay I, Kaminski RW, Sack DA, Zhang W. A broadly immunogenic polyvalent Shigella multiepitope fusion antigen protein protects against Shigella sonnei and Shigella flexneri lethal pulmonary challenges in mice. Infect Immun 2023; 91:e0031623. [PMID: 37795982 PMCID: PMC10652900 DOI: 10.1128/iai.00316-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 08/21/2023] [Indexed: 10/06/2023] Open
Abstract
There are no licensed vaccines for Shigella, a leading cause of children's diarrhea and a common etiology of travelers' diarrhea. To develop a cross-protective Shigella vaccine, in this study, we constructed a polyvalent protein immunogen to present conserved immunodominant epitopes of Shigella invasion plasmid antigens B (IpaB) and D (IpaD), VirG, GuaB, and Shiga toxins on backbone protein IpaD, by applying an epitope- and structure-based multiepitope-fusion-antigen (MEFA) vaccinology platform, examined protein (Shigella MEFA) broad immunogenicity, and evaluated antibody function against Shigella invasion and Shiga toxin cytotoxicity but also protection against Shigella lethal challenge. Mice intramuscularly immunized with Shigella MEFA protein developed IgG responses to IpaB, IpaD, VirG, GuaB, and Shiga toxins 1 and 2; mouse sera significantly reduced invasion of Shigella sonnei, Shigella flexneri serotype 2a, 3a, or 6, Shigella boydii, and Shigella dysenteriae type 1 and neutralized cytotoxicity of Shiga toxins of Shigella and Shiga toxin-producing Escherichia coli in vitro. Moreover, mice intranasally immunized with Shigella MEFA protein (adjuvanted with dmLT) developed antigen-specific serum IgG, lung IgG and IgA, and fecal IgA antibodies, and survived from lethal pulmonary challenge with S. sonnei or S. flexneri serotype 2a, 3a, or 6. In contrast, the control mice died, became unresponsive, or lost 20% of body weight in 48 h. These results indicated that this Shigella MEFA protein is broadly immunogenic, induces broadly functional antibodies, and cross-protects against lethal pulmonary challenges with S. sonnei or S. flexneri serotypes, suggesting a potential application of this polyvalent MEFA protein in Shigella vaccine development.
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Affiliation(s)
- Siqi Li
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Shaghayegh Anvari
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, Kansas, USA
| | - Galen Ptacek
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ipshita Upadhyay
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Robert W. Kaminski
- Department of Enteric Infections, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - David A. Sack
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Weiping Zhang
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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3
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Duplessis C, Clarkson KA, Ross Turbyfill K, Alcala AN, Gutierrez R, Riddle MS, Lee T, Paolino K, Weerts HP, Lynen A, Oaks EV, Porter CK, Kaminski R. GMP manufacture of Shigella flexneri 2a Artificial Invaplex (Invaplex AR) and evaluation in a Phase 1 Open-label, dose escalating study administered intranasally to healthy, adult volunteers. Vaccine 2023; 41:6261-6271. [PMID: 37666695 DOI: 10.1016/j.vaccine.2023.08.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/14/2023] [Accepted: 08/19/2023] [Indexed: 09/06/2023]
Abstract
Shigella species cause severe disease among travelers to, and children living in, endemic countries. Although significant efforts have been made to improve sanitation, increased antibiotic resistance and other factors suggest an effective vaccine is a critical need. Artificial Invaplex (InvaplexAR) is a subunit vaccine approach complexing Shigella LPS with invasion plasmid antigens. In pre-clinical studies, the InvaplexAR vaccine demonstrated increased immunogenicity as compared to the first generation product and was subsequently manufactured under cGMP for clinical testing in a first-in-human Phase 1 study. The primary objective of this study was the safety of S. flexneri 2a InvaplexAR given by intranasal (IN) immunization (without adjuvant) in a single-center, open-label, dose-escalating Phase 1 trial and secondarily to assess immunogenicity to identify a dose of InvaplexAR for subsequent clinical evaluations. Subjects received three IN immunizations of InvaplexAR, two weeks apart, in increasing dose cohorts (10 µg, 50 µg, 250 µg, and 500 μg). Adverse events were monitored using symptom surveillance, memory aids, and targeted physical exams. Samples were collected throughout the study to investigate vaccine-induced systemic and mucosal immune responses. There were no adverse events that met vaccination-stopping criteria. The majority (96%) of vaccine-related adverse events were mild in severity (most commonly nasal congestion, rhinorrhea, and post-nasal drip). Vaccination with InvaplexAR induced anti-LPS serum IgG responses and anti-Invaplex IgA and IgG antibody secreting cell (ASC) responses at vaccine doses ≥250 µg. Additionally, mucosal immune responses and functional antibody responses were seen from the serum bactericidal assay measurements. Notably, the responder rates and the kinetics of ASCs and antibody lymphocyte secretion (ALS) were similar, suggesting that either assay may be employed to identify IgG and IgA secreting cells. Further studies with InvaplexAR will evaluate alternative immunization routes, vaccination schedules and formulations to further optimize immunogenicity. (Clinical Trial Registry Number NCT02445963).
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Affiliation(s)
- Christopher Duplessis
- Naval Medical Research Command, Silver Spring, MD, USA; Current Affiliation: University of Nevada Reno, Reno, NV, USA
| | - Kristen A Clarkson
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Current Affiliation: Horizon Therapeutics, Deerfield, IL, USA
| | - K Ross Turbyfill
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Ashley N Alcala
- Naval Medical Research Command, Silver Spring, MD, USA; Current Affiliation: Tigermed-BDM, Somerset, NJ, USA
| | - Ramiro Gutierrez
- Naval Medical Research Command, Silver Spring, MD, USA; Current Affiliation: Upstate Medical University, Syracuse, NY, USA
| | - Mark S Riddle
- Naval Medical Research Command, Silver Spring, MD, USA; Current Affiliation: University of Nevada Reno, Reno, NV, USA
| | - Tida Lee
- Naval Medical Research Command, Silver Spring, MD, USA
| | - Kristopher Paolino
- Clinical Trials Center, Division of Translational Medicine, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Current Affiliation: Upstate Medical University, Syracuse, NY, USA
| | - Hailey P Weerts
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Current Affiliation: National Institute of Allery and Infectious Diseases, Bethesda, MD, USA
| | - Amanda Lynen
- Naval Medical Research Command, Silver Spring, MD, USA
| | - Edwin V Oaks
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Current Affiliation: Patuxent Research and Consulting Group, Gambrills, MD, USA
| | - Chad K Porter
- Naval Medical Research Command, Silver Spring, MD, USA
| | - Robert Kaminski
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Current Affiliation: Latham BioPharm Group, Cambridge, MA, USA
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Bernshtein B, Ndungo E, Cizmeci D, Xu P, Kováč P, Kelly M, Islam D, Ryan ET, Kotloff KL, Pasetti MF, Alter G. Systems approach to define humoral correlates of immunity to Shigella. Cell Rep 2022; 40:111216. [PMID: 35977496 PMCID: PMC9396529 DOI: 10.1016/j.celrep.2022.111216] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/22/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
Shigella infection is the second leading cause of death due to diarrheal disease in young children worldwide. With the rise of antibiotic resistance, initiatives to design and deploy a safe and effective Shigella vaccine are urgently needed. However, efforts to date have been hindered by the limited understanding of immunological correlates of protection against shigellosis. We applied systems serology to perform a comprehensive analysis of Shigella-specific antibody responses in sera obtained from volunteers before and after experimental infection with S. flexneri 2a in a series of controlled human challenge studies. Polysaccharide-specific antibody responses are infrequent prior to infection and evolve concomitantly with disease severity. In contrast, pre-existing antibody responses to type 3 secretion system proteins, particularly IpaB, consistently associate with clinical protection from disease. Linked to particular Fc-receptor binding patterns, IpaB-specific antibodies leverage neutrophils and monocytes, and complement and strongly associate with protective immunity. IpaB antibody-mediated functions improve with a subsequent rechallenge resulting in complete clinical protection. Collectively, our systems serological analyses indicate protein-specific functional correlates of immunity against Shigella in humans. Serological profiling of Shigella human challenge studies indicates protective markers Pre-existing IpaB-specific functional antibodies associate with less severe disease OPS immune responses post challenge are linked to less severe disease Shigella rechallenge boosts IpaB but not OPS functional antibody responses
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Affiliation(s)
| | - Esther Ndungo
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Deniz Cizmeci
- Ragon Institute of MGH, Harvard and MIT, Cambridge, MA, USA
| | - Peng Xu
- NIDDK, LBC, National Institutes of Health, Bethesda, MD, USA
| | - Pavol Kováč
- NIDDK, LBC, National Institutes of Health, Bethesda, MD, USA
| | - Meagan Kelly
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA
| | - Dilara Islam
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Karen L Kotloff
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Marcela F Pasetti
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Galit Alter
- Ragon Institute of MGH, Harvard and MIT, Cambridge, MA, USA.
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5
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Li S, Han X, Upadhyay I, Zhang W. Characterization of Functional B-Cell Epitopes at the Amino Terminus of Shigella Invasion Plasmid Antigen B (IpaB). Appl Environ Microbiol 2022; 88:e0038422. [PMID: 35856689 PMCID: PMC9361828 DOI: 10.1128/aem.00384-22] [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: 03/01/2022] [Accepted: 06/29/2022] [Indexed: 01/22/2023] Open
Abstract
Shigella invasion plasmid antigen B (IpaB) plays an important role in causing shigellosis. While IpaB's protein structure, contribution to disease mechanism, and protective immunity against Shigella infection have been well studied, the significance of individual antigenic domains, especially at the N terminus, has not been systematically characterized. In an attempt to identify IpaB protein functional epitopes and to construct an optimized polyvalent multiepitope fusion antigen (MEFA) immunogen for development of a protein-based cross protective Shigella vaccine, in this study, we in silico identified immunodominant B-cell epitopes from the IpaB N terminus, fused each epitope to carrier protein CsaB (the major subunit of enterotoxigenic Escherichia coli CS4 adhesin) for epitope fusion proteins, immunized mice with each epitope fusion protein, examined IpaB-specific antibody responses, and assessed antibody functional activity against Shigella bacterial invasion. A total of 10 B-cell continuous epitopes were identified from IpaB N terminus, and after being fused to carrier protein CsaB, each epitope induced anti-IpaB IgG responses in the intramuscularly immunized mice. While in vitro antibody invasion inhibition assays demonstrated that antibodies derived from each identified epitope were functional, epitopes 1 (LAKILASTELGDNTIQAA), 2 (HSTSNILIPELKAPKSL), and 4 (QARQQKNLEFSDKI) induced antibodies to inhibit Shigella sonnei and Shigella flexneri invasion at levels similar to those of recombinant IpaB protein, suggesting that these three IpaB epitopes can be used potentially as IpaB-representing antigens to induce protective anti-IpaB antibodies and for construction of an epitope-based polyvalent MEFA protein immunogen for Shigella vaccine development. IMPORTANCE Currently, there are no effective measures for control or prevention of Shigella infection, the most common cause of diarrhea in children 3 to 5 years of age in developing countries. Challenges in developing Shigella vaccines include virulence heterogeneity among species and serotypes. To overcome virulence heterogeneity challenge and to develop a protein-based multivalent Shigella vaccine, we targeted a panel of virulence factors, including invasion plasmid antigens, identified functional antigenic domains or epitopes as representative antigens, and applied the novel epitope- and structure-based vaccinology platform multiepitope fusion antigen (MEFA) to integrate functional antigenic domains or epitopes into a backbone immunogen to produce a polyvalent immunogen for cross protective antibodies. Identification of functional IpaB epitopes from this study enhances our understanding of IpaB immunogenicity and allows us to directly utilize IpaB epitopes for construction of a cross protective polyvalent Shigella immunogen and to accelerate development of a protein-based Shigella vaccine.
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Affiliation(s)
- Siqi Li
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Xinfeng Han
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Sichuan Agricultural University College of Veterinary Medicine, Chengdu, Sichuan, People’s Republic of China
| | - Ipshita Upadhyay
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Weiping Zhang
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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6
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Palit P, Chowdhury FT, Baruah N, Sarkar B, Mou SN, Kamal M, Siddiqua TJ, Noor Z, Ahmed T. A Comprehensive Computational Investigation into the Conserved Virulent Proteins of Shigella species Unveils Potential Small-Interfering RNA Candidates as a New Therapeutic Strategy against Shigellosis. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27061936. [PMID: 35335300 PMCID: PMC8950558 DOI: 10.3390/molecules27061936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/19/2021] [Accepted: 12/27/2021] [Indexed: 11/16/2022]
Abstract
Shigella species account for the second-leading cause of deaths due to diarrheal diseases among children of less than 5 years of age. The emergence of multi-drug-resistant Shigella isolates and the lack of availability of Shigella vaccines have led to the pertinence in the efforts made for the development of new therapeutic strategies against shigellosis. Consequently, designing small-interfering RNA (siRNA) candidates against such infectious agents represents a novel approach to propose new therapeutic candidates to curb the rampant rise of anti-microbial resistance in such pathogens. In this study, we analyzed 264 conserved sequences from 15 different conserved virulence genes of Shigella sp., through extensive rational validation using a plethora of first-generation and second-generation computational algorithms for siRNA designing. Fifty-eight siRNA candidates were obtained by using the first-generation algorithms, out of which only 38 siRNA candidates complied with the second-generation rules of siRNA designing. Further computational validation showed that 16 siRNA candidates were found to have a substantial functional efficiency, out of which 11 siRNA candidates were found to be non-immunogenic. Finally, three siRNA candidates exhibited a sterically feasible three-dimensional structure as exhibited by parameters of nucleic acid geometry such as: the probability of wrong sugar puckers, bad backbone confirmations, bad bonds, and bad angles being within the accepted threshold for stable tertiary structure. Although the findings of our study require further wet-lab validation and optimization for therapeutic use in the treatment of shigellosis, the computationally validated siRNA candidates are expected to suppress the expression of the virulence genes, namely: IpgD (siRNA 9) and OspB (siRNA 15 and siRNA 17) and thus act as a prospective tool in the RNA interference (RNAi) pathway. However, the findings of our study require further wet-lab validation and optimization for regular therapeutic use for treatment of shigellosis.
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Affiliation(s)
- Parag Palit
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (P.P.); (M.K.); (T.J.S.); (T.A.)
| | - Farhana Tasnim Chowdhury
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka 1000, Bangladesh; (F.T.C.); (B.S.); (S.N.M.)
| | - Namrata Baruah
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh, India;
| | - Bonoshree Sarkar
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka 1000, Bangladesh; (F.T.C.); (B.S.); (S.N.M.)
| | - Sadia Noor Mou
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka 1000, Bangladesh; (F.T.C.); (B.S.); (S.N.M.)
| | - Mehnaz Kamal
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (P.P.); (M.K.); (T.J.S.); (T.A.)
| | - Towfida Jahan Siddiqua
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (P.P.); (M.K.); (T.J.S.); (T.A.)
| | - Zannatun Noor
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (P.P.); (M.K.); (T.J.S.); (T.A.)
- Correspondence:
| | - Tahmeed Ahmed
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka 1212, Bangladesh; (P.P.); (M.K.); (T.J.S.); (T.A.)
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7
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Efficient production of immunologically active Shigella invasion plasmid antigens IpaB and IpaH using a cell-free expression system. Appl Microbiol Biotechnol 2021; 106:401-414. [PMID: 34932164 PMCID: PMC8688910 DOI: 10.1007/s00253-021-11701-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 11/16/2022]
Abstract
Abstract Shigella spp. invade the colonic epithelium and cause bacillary dysentery in humans. Individuals living in areas that lack access to clean water and sanitation are the most affected. Even though infection can be treated with antibiotics, Shigella antimicrobial drug resistance complicates clinical management. Despite decades of effort, there are no licensed vaccines to prevent shigellosis. The highly conserved invasion plasmid antigens (Ipa), which are components of the Shigella type III secretion system, participate in bacterial epithelial cell invasion and have been pursued as vaccine targets. However, expression and purification of these proteins in conventional cell-based systems have been challenging due to solubility issues and extremely low recovery yields. These difficulties have impeded manufacturing and clinical advancement. In this study, we describe a new method to express Ipa proteins using the Xpress+TM cell-free protein synthesis (CFPS) platform. Both IpaB and the C-terminal domain of IpaH1.4 (IpaH-CTD) were efficiently produced with this technology at yields > 200 mg/L. Furthermore, the expression was linearly scaled in a bioreactor under controlled conditions, and proteins were successfully purified using multimode column chromatography to > 95% purity as determined by SDS-PAGE. Biophysical characterization of the cell-free synthetized IpaB and IpaH-CTD using SEC-MALS analysis showed well-defined oligomeric states of the proteins in solution. Functional analysis revealed similar immunoreactivity as compared to antigens purified from E. coli. These results demonstrate the efficiency of CFPS for Shigella protein production; the practicality and scalability of this method will facilitate production of antigens for Shigella vaccine development and immunological analysis. Key points • First report of Shigella IpaB and IpaH produced at high purity and yield using CFPS • CFPS-IpaB and IpaH perform similarly to E. coli–produced proteins in immunoassays • CFPS-IpaB and IpaH react with Shigella-specific human antibodies and are immunogenic in mice. Graphical abstract ![]()
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8
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Ndungo E, Andronescu LR, Buchwald AG, Lemme-Dumit JM, Mawindo P, Kapoor N, Fairman J, Laufer MK, Pasetti MF. Repertoire of Naturally Acquired Maternal Antibodies Transferred to Infants for Protection Against Shigellosis. Front Immunol 2021; 12:725129. [PMID: 34721387 PMCID: PMC8554191 DOI: 10.3389/fimmu.2021.725129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Shigella is the second leading cause of diarrheal diseases, accounting for >200,000 infections and >50,000 deaths in children under 5 years of age annually worldwide. The incidence of Shigella-induced diarrhea is relatively low during the first year of life and increases substantially, reaching its peak between 11 to 24 months of age. This epidemiological trend hints at an early protective immunity of maternal origin and an increase in disease incidence when maternally acquired immunity wanes. The magnitude, type, antigenic diversity, and antimicrobial activity of maternal antibodies transferred via placenta that can prevent shigellosis during early infancy are not known. To address this knowledge gap, Shigella-specific antibodies directed against the lipopolysaccharide (LPS) and virulence factors (IpaB, IpaC, IpaD, IpaH, and VirG), and antibody-mediated serum bactericidal (SBA) and opsonophagocytic killing antibody (OPKA) activity were measured in maternal and cord blood sera from a longitudinal cohort of mother-infant pairs living in rural Malawi. Protein-specific (very high levels) and Shigella LPS IgG were detected in maternal and cord blood sera; efficiency of placental transfer was 100% and 60%, respectively, and had preferential IgG subclass distribution (protein-specific IgG1 > LPS-specific IgG2). In contrast, SBA and OPKA activity in cord blood was substantially lower as compared to maternal serum and varied among Shigella serotypes. LPS was identified as the primary target of SBA and OPKA activity. Maternal sera had remarkably elevated Shigella flexneri 2a LPS IgM, indicative of recent exposure. Our study revealed a broad repertoire of maternally acquired antibodies in infants living in a Shigella-endemic region and highlights the abundance of protein-specific antibodies and their likely contribution to disease prevention during the first months of life. These results contribute new knowledge on maternal infant immunity and target antigens that can inform the development of vaccines or therapeutics that can extend protection after maternally transferred immunity wanes.
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Affiliation(s)
- Esther Ndungo
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Liana R. Andronescu
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Andrea G. Buchwald
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jose M. Lemme-Dumit
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Patricia Mawindo
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | | | | | - Miriam K. Laufer
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Marcela F. Pasetti
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
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9
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Felegary A, Nazarian S, Kordbacheh E, Fathi J, Minae ME. An approach to chimeric subunit immunogen provides efficient protection against toxicity, type III and type v secretion systems of Shigella. Int Immunopharmacol 2021; 100:108132. [PMID: 34508943 DOI: 10.1016/j.intimp.2021.108132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Shigellosis is one of the infectious diseases causing severe intestinal illness in human beings. Development of an effective vaccine against Shigella is a key to deal with this bacterium. The present study aimed at evaluation of the antibody response as well as the protection of the recombinant chimeric protein containing IpaD, IpaB, StxB, and VirG against Shigella dysentery and flexneri. METHODS Chimeric protein was expressed and purified by Ni-NTA resin. The identity of the protein was determined by Western blot analysis. Mouse groups were immunized with the recombinant protein and the humoral immune response was measured by Enzyme-Linked Immunosorbent Assay (ELISA). Additionally, neutralization of the bacterial toxin by antibody was assessed by MTT assay. Animal challenge against S.dysentery and S. flexneri was evaluated, as well. RESULTS Protein expression and purification were confirmed by SDS-PAGE and western blotting. Analysis of the immune responses demonstrated that the antibody responses were higher in the sera of the subcutaneously immunized mice compared to those immunized intraperitoneally. In vitro neutralization analysis indicated that the 1:10000 dilution of the sera had a high ability to neutralize 0.25 ng/µl (CD50) of the toxin on the Vero cell line. Furthermore, the results of the animal challenge showed that the immunized mice were completely protected against 50 LD50 of the bacterial toxin. Immunization also protected 80% of the mice from 10 LD50 by S. flexneri and S.dysentery. In addition, passive immunization conferred 60% protection in the mice against S. flexneri and S.dysentery. Organ burden studies also revealed a significant reduction in infection among the immunized mice. CONCLUSION This study revealed that the chimeric protein produced inE. colicould be a promising chimeric immunogen candidate against Shigella.
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Affiliation(s)
- Alireza Felegary
- Department of Biological Sciences, Faculty of Science, Imam Hossein University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biological Sciences, Faculty of Science, Imam Hossein University, Tehran, Iran.
| | - Emad Kordbacheh
- Department of Biological Sciences, Faculty of Science, Imam Hossein University, Tehran, Iran
| | - Javad Fathi
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohamad Ebrahim Minae
- Department of Biological Sciences, Faculty of Science, Imam Hossein University, Tehran, Iran
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10
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Sierocki R, Jneid B, Orsini Delgado ML, Plaisance M, Maillère B, Nozach H, Simon S. An antibody targeting type III secretion system induces broad protection against Salmonella and Shigella infections. PLoS Negl Trop Dis 2021; 15:e0009231. [PMID: 33711056 PMCID: PMC7990167 DOI: 10.1371/journal.pntd.0009231] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/24/2021] [Accepted: 02/11/2021] [Indexed: 11/18/2022] Open
Abstract
Salmonella and Shigella bacteria are food- and waterborne pathogens that are responsible for enteric infections in humans and are still the major cause of morbidity and mortality in the emerging countries. The existence of multiple Salmonella and Shigella serotypes as well as the emergence of strains resistant to antibiotics requires the development of broadly protective therapies. Recently, the needle tip proteins of the type III secretion system of these bacteria were successfully utilized (SipD for Salmonella and IpaD for Shigella) as vaccine immunogens to provide good prophylactic cross-protection in murine models of infections. From these experiments, we have isolated a cross-protective monoclonal antibody directed against a conserved region of both proteins. Its conformational epitope determined by Deep Mutational Scanning is conserved among needle tip proteins of all pathogenic Shigella species and Salmonella serovars, and are well recognized by this antibody. Our study provides the first in vivo experimental evidence of the importance of this common region in the mechanism of virulence of Salmonella and Shigella and opens the way to the development of cross-protective therapeutic agents. Salmonella and Shigella are responsible for gastrointestinal diseases and continue to remain a serious health hazard in South and South-East Asia and African countries, even more with the new emergence of multi drug resistances. Developed vaccines are either not commercialized (for Shigella) or cover only a limited number of serotypes (for Salmonella). There is thus a crucial need to develop cross-protective therapies. By targeting proteins SipD and IpaD belonging respectively to the injectisome of Salmonella and Shigella and necessary to their virulence, we have shown that a monoclonal antibody (mAb) directed against a conserved common region of their apical part provides good cross-protection prophylactic efficacy. We have determined the region targeted by this mAb which could explain why it is conserved among Salmonella and Shigella bacteria.
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Affiliation(s)
- Raphaël Sierocki
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SIMoS, Gif-sur-Yvette, France
| | - Bakhos Jneid
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Maria Lucia Orsini Delgado
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Marc Plaisance
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Bernard Maillère
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SIMoS, Gif-sur-Yvette, France
| | - Hervé Nozach
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SIMoS, Gif-sur-Yvette, France
| | - Stéphanie Simon
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
- * E-mail:
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11
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The Shigella Type III Secretion System: An Overview from Top to Bottom. Microorganisms 2021; 9:microorganisms9020451. [PMID: 33671545 PMCID: PMC7926512 DOI: 10.3390/microorganisms9020451] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 12/16/2022] Open
Abstract
Shigella comprises four species of human-restricted pathogens causing bacillary dysentery. While Shigella possesses multiple genetic loci contributing to virulence, a type III secretion system (T3SS) is its primary virulence factor. The Shigella T3SS nanomachine consists of four major assemblies: the cytoplasmic sorting platform; the envelope-spanning core/basal body; an exposed needle; and a needle-associated tip complex with associated translocon that is inserted into host cell membranes. The initial subversion of host cell activities is carried out by the effector functions of the invasion plasmid antigen (Ipa) translocator proteins, with the cell ultimately being controlled by dedicated effector proteins that are injected into the host cytoplasm though the translocon. Much of the information now available on the T3SS injectisome has been accumulated through collective studies on the T3SS from three systems, those of Shigella flexneri, Salmonella typhimurium and Yersinia enterocolitica/Yersinia pestis. In this review, we will touch upon the important features of the T3SS injectisome that have come to light because of research in the Shigella and closely related systems. We will also briefly highlight some of the strategies being considered to target the Shigella T3SS for disease prevention.
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12
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Das S, Howlader DR, Zheng Q, Ratnakaram SSK, Whittier SK, Lu T, Keith JD, Picking WD, Birket SE, Picking WL. Development of a Broadly Protective, Self-Adjuvanting Subunit Vaccine to Prevent Infections by Pseudomonas aeruginosa. Front Immunol 2020; 11:583008. [PMID: 33281815 PMCID: PMC7705240 DOI: 10.3389/fimmu.2020.583008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
Infections caused by the opportunistic pathogen Pseudomonas aeruginosa can be difficult to treat due to innate and acquired antibiotic resistance and this is exacerbated by the emergence of multi-drug resistant strains. Unfortunately, no licensed vaccine yet exists to prevent Pseudomonas infections. Here we describe a novel subunit vaccine that targets the P. aeruginosa type III secretion system (T3SS). This vaccine is based on the novel antigen PaF (Pa Fusion), a fusion of the T3SS needle tip protein, PcrV, and the first of two translocator proteins, PopB. Additionally, PaF is made self-adjuvanting by the N-terminal fusion of the A1 subunit of the mucosal adjuvant double-mutant heat-labile enterotoxin (dmLT). Here we show that this triple fusion, designated L-PaF, can activate dendritic cells in vitro and elicits strong IgG and IgA titers in mice when administered intranasally. This self-adjuvanting vaccine expedites the clearance of P. aeruginosa from the lungs of challenged mice while stimulating host expression of IL-17A, which may be important for generating a protective immune response in humans. L-PaF's protective capacity was recapitulated in a rat pneumonia model, further supporting the efficacy of this novel fusion vaccine.
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Affiliation(s)
- Sayan Das
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Debaki R Howlader
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Qi Zheng
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Siva Sai Kumar Ratnakaram
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Sean K Whittier
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States.,Hafion LLC, Lawrence, KS, United States
| | - Ti Lu
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Johnathan D Keith
- Department of Medicine and Gregory Fleming James Cystic Fibrosis Research Center, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - William D Picking
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States
| | - Susan E Birket
- Department of Medicine and Gregory Fleming James Cystic Fibrosis Research Center, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Wendy L Picking
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS, United States.,Hafion LLC, Lawrence, KS, United States
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13
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Jneid B, Rouaix A, Féraudet-Tarisse C, Simon S. SipD and IpaD induce a cross-protection against Shigella and Salmonella infections. PLoS Negl Trop Dis 2020; 14:e0008326. [PMID: 32463817 PMCID: PMC7282677 DOI: 10.1371/journal.pntd.0008326] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/09/2020] [Accepted: 04/26/2020] [Indexed: 01/05/2023] Open
Abstract
Salmonella and Shigella species are food- and water-borne pathogens that are responsible for enteric infections in both humans and animals and are still the major cause of morbidity and mortality in the emerging countries. The existence of multiple Salmonella and Shigella serotypes as well as the emergence of strains resistant to antibiotics require the development of broadly protective therapies. Those bacteria utilize a Type III Secretion System (T3SS), necessary for their pathogenicity. The structural proteins composing the T3SS are common to all virulent Salmonella and Shigella spp., particularly the needle-tip proteins SipD (Salmonella) and IpaD (Shigella). We investigated the immunogenicity and protective efficacy of SipD and IpaD administered by intranasal and intragastric routes, in a mouse model of Salmonella enterica serotype Typhimurium (S. Typhimurium) intestinal challenge. Robust IgG (in all immunization routes) and IgA (in intranasal and oral immunization routes) antibody responses were induced against both proteins. Mice immunized with SipD or IpaD were protected against lethal intestinal challenge with S. Typhimurium or Shigella flexneri (100 Lethal Dose 50%). We have shown that SipD and IpaD are able to induce a cross-protection in a murine model of infection by Salmonella and Shigella. We provide the first demonstration that Salmonella and Shigella T3SS SipD and IpaD are promising antigens for the development of a cross-protective Salmonella-Shigella vaccine. These results open the way to the development of cross-protective therapeutic molecules.
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Affiliation(s)
- Bakhos Jneid
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Audrey Rouaix
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Cécile Féraudet-Tarisse
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Stéphanie Simon
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
- * E-mail:
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14
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Heterologous expression of Intimin and IpaB fusion protein in Lactococcus lactis and its mucosal delivery elicit protection against pathogenicity of Escherichia coli O157 and Shigella flexneri in a murine model. Int Immunopharmacol 2020; 85:106617. [PMID: 32464569 DOI: 10.1016/j.intimp.2020.106617] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/16/2020] [Accepted: 05/17/2020] [Indexed: 12/12/2022]
Abstract
Escherichia coli O157:H7 and Shigella flexneri are the predominant diarrhoeal pathogens and those strains producing Shiga toxins cause life-threatening sequelae including hemolytic uremic syndrome (HUS) upon their entry into the host. Intimate adherence of E. coli O157 and invasion of S. flexneri in the host intestinal epithelial cells is mainly mediated by Intimin and IpaB proteins, respectively. In this study, we have synthesized chimera of immunodominant regions of Intimin (eae) and IpaB (ipaB) designated as EI and expressed it in Lactococcus lactis (LL-EI) to develop a combinatorial oral vaccine candidate. Immune parameters and protective efficacy of orally administered LL-EI were assessed in the murine model. Significant EI-specific serum IgG, IgA, and fecal IgA antibody titer were observed in the LL-EI group. Considerable increase in EI-specific splenocyte proliferation and a concurrent upregulation of both Th1 and Th2 cytokines was observed in LL-EI immunized mice. Flow cytometry analysis also revealed a significant increase in CD4 and CD8 cell counts in LL-EI immunized group compared to PBS, LL control group.In vitro studies using LL-EI immunized mice sera showed substantial protection against bacterial adhesion and invasion caused by E. coli O157 and Shigella flexneri¸ respectively. LL-EI immunized group challenged with E. coli O157 ceased fecal shedding within 6 days, and mice challenged with S. flexneri showed 93% survival with minimal bacterial load in the lungs. Our results indicate that LL-EI immunization elicits systemic, mucosal and cell-mediated immune responses, and can be a promising candidate for oral vaccine development against these pathogens.
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15
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In-silico design and production of a novel antigenic chimeric Shigella IpaB fused to C-terminal of Clostridium perfringens enterotoxin. Mol Biol Rep 2019; 46:6105-6115. [PMID: 31473892 DOI: 10.1007/s11033-019-05046-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 08/27/2019] [Indexed: 10/26/2022]
Abstract
The emergence of antibiotic-resistant phenotypes in Shigella serotypes and the high mortality rate, approximately one million dead annually, in affected patients announce a global demand for an effective serotype-independent vaccine against Shigella. This study aims to design, express, and purify a novel chimeric protein, as a serotype-independent vaccine candidate against Shigella containing full-length Shigella invasion plasmid antigen B (IpaB) and a C-terminal fragment (residues 194-319) of Clostridium perfringens enterotoxin (C-CPE) as a mucosal adjuvant. Several online databases and bioinformatics software were utilized to design the chimeric protein and the relative recombinant gene. The recombinant gene encoding IpaB-CPE194-319 was synthesized, cloned into pACYCDuet-1 expression vector, and transferred to E. coli Bl21 (DE3) cells. IpaB-CPE194-319 was then expressed in auto-induction medium, purified and characterized using MALDI-TOF-TOF mass spectrometry. Followed by subcutaneous injection of the purified IpaB-CPE194-319 to BALB/c mice, antigenicity of this chimeric protein was determined through performing dot-blot immunoassay on nitrocellulose membrane using mice sera. The outcomes of this study show the successful design, efficient expression, and purification of IpaB-CPE194-319 divalent chimeric protein under mentioned conditions. The obtained results also demonstrate the intrinsic antigenic property of IpaB-CPE194-319.
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16
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Heine SJ, Franco-Mahecha OL, Sears KT, Drachenberg CB, van Roosmalen ML, Leenhouts K, Picking WL, Pasetti MF. A Combined YopB and LcrV Subunit Vaccine Elicits Protective Immunity against Yersinia Infection in Adult and Infant Mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2019; 202:2005-2016. [PMID: 30787109 PMCID: PMC6424635 DOI: 10.4049/jimmunol.1800985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/23/2019] [Indexed: 11/19/2022]
Abstract
Yersinia enterocolitica causes a severe enteric infection in infants and young children. There is no vaccine approved for use in humans. We investigated the immunogenicity and protective capacity of Yersinia YopB, a conserved type III secretion system protein, alone or combined with LcrV in adult mice immunized intranasally. YopB or LcrV (5 μg) administered with the Escherichia coli double mutant heat-labile toxin (dmLT) adjuvant afforded modest (10-30%) protection against lethal Y. enterocolitica oral infection. The combination of YopB and LcrV (5 μg each) dramatically improved vaccine efficacy (70-80%). Additionally, it afforded complete protection against Y. pestis pulmonary infection. Immunization with YopB/LcrV+dmLT resulted in Ag-specific serum IgG, systemic and mucosal Ab-secreting cells, as well as IFN-γ, TNF-α, IL-2, IL-6, IL-17A, and KC production by spleen cells. Serum Abs elicited by YopB/LcrV+dmLT had enhanced bactericidal and opsonophagocytic killing activity. After Y. enterocolitica challenge, YopB/LcrV+dmLT-vaccinated mice exhibited intact intestinal tissue, active germinal centers in mesenteric lymph nodes, IgG+ and IgA+ plasmablasts in the lamina propria, and Abs in intestinal fluid. On the contrary, complete tissue destruction and abscesses were seen in placebo recipients that succumbed to infection. Mice immunized as infants with YopB+dmLT or LcrV+dmLT achieved 60% protection against lethal Y. enterocolitica infection, and vaccine efficacy increased to 90-100% when they received YopB/LcrV+dmLT. YopB+dmLT also afforded substantial (60%) protection when administered intradermally to infant mice. YopB/LcrV+dmLT is a promising subunit vaccine candidate with the potential to elicit broad protection against Yersinia spp.
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Affiliation(s)
- Shannon J Heine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Olga L Franco-Mahecha
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Khandra T Sears
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Cinthia B Drachenberg
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201
| | | | | | - Wendy L Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201;
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201
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17
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Arizmendi O, Kumar P, Zheng Q, Stewart JP, Picking WD, Picking W, Martinez-Becerra FJ. Vaccination With Mouse Dendritic Cells Loaded With an IpaD-IpaB Fusion Provides Protection Against Shigellosis. Front Immunol 2019; 10:192. [PMID: 30800131 PMCID: PMC6376248 DOI: 10.3389/fimmu.2019.00192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022] Open
Abstract
Diarrheal diseases are a major cause of morbidity and mortality worldwide. They are most prevalent in settings with inadequate sanitation, poor hygiene and contaminated water. An important diarrheal pathogen in such settings is Shigella. No commercially available vaccine exists against shigellosis and immunity to the pathogen is serotype-restricted. We have previously shown that a polypeptide fusion of the Type Three Secretion Apparatus (T3SA) proteins IpaB and IpaD (named DBF) was efficacious as a vaccine against Shigella. Vaccination using different administration routes indicated that protection conferred by DBF did not fully correlate with antibodies. To define the immune responses involved in protection, we studied cellular responses to intranasal immunization with the DBF and the adjuvant dmLT. We found dendritic cell (DC) activation at the nasal associated lymphoid tissue (NALT). Activation markers CD86 and MHCII significantly increase in cells from immunized mice. Antigen exposure in vitro further confirmed the upregulation of CD80 and CD40 in primary dendritic cells. Animals immunized with antigen-primed dendritic cells were protected against Shigella infection, at levels comparable to the efficacy of immunization with the protein vaccine formulation. Therefore, we show that antigen-primed DCs are enough to provide immunity, and propose a mechanism of protection against Shigella spp. based on DC-mediated antigen presentation to T cells.
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Affiliation(s)
- Olivia Arizmendi
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, United States
| | - Prashant Kumar
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, United States
| | - Qi Zheng
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Jason P Stewart
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - William D Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
| | - Wendy Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, United States
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18
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Davod J, Fatemeh DN, Honari H, Hosseini R. Constructing and transient expression of a gene cassette containing edible vaccine elements and shigellosis, anthrax and cholera recombinant antigens in tomato. Mol Biol Rep 2018; 45:2237-2246. [PMID: 30244396 PMCID: PMC7088786 DOI: 10.1007/s11033-018-4385-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 09/12/2018] [Indexed: 12/04/2022]
Abstract
Shigella dysenteriae causing shigellosis is one of the diseases that threaten the health of human society in the developing countries. In Shigella, IpaD gene is one of the key pathogenic genes causing strong mucosal immune system reactions. Anthrax disease is caused by Bacillus anthracis. PA protective antigen is one of the subunits in anthrax toxin complex responsible for the transfer of other subunits into the cytosol of host cells. The 20 kDa subunit of PA (PA20) has the property of immunogenicity. CTxB or B subunit of Vibrio cholerae toxin (CT) is a non-toxic protein and has the function to transfer toxic subunit into cytosol of the host cells by binding to GM1 receptor. The aim of this study was to fuse PA20, ipaD and CTxB and transform tomato plants by this cassette in order to produce an oral vaccine against shigellosis, anthrax and cholera. CTxB was used for these two antigens as an immune adjuvant. IpaD and PA20 genes were cloned in pBI121 containing the CTxB gene and Extensin signal peptide. In order to evaluate the transient expression of Shigellosis, Anthrax and Cholera antigens, agro-infiltrated tomato tissues were inoculated with Agrobacterium tumefaciens containing the gene cassette. Cloning was confirmed by PCR, enzymatic digestion and sequencing techniques. Expression of the antigens was examined by SDS-PAGE, dot blot and ELISA. Maturate green fruits demonstrated the highest expression of the recombinant proteins. The first phase of this study was carried out for cloning and expressing of CtxB, ipaD and PA20 antigens in tomato. In the next phase, we aim to analyze the immunogenicity of this vaccine candidate in laboratory animals.
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Affiliation(s)
- Jafari Davod
- Medical Biotechnology Department, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.,Biotechnology Department, Faculty of Agricultural and Natural Sciences, Imam Khomeini International University (IKIU), Qazvin, Iran
| | - Dehghan Nayeri Fatemeh
- Biotechnology Department, Faculty of Agricultural and Natural Sciences, Imam Khomeini International University (IKIU), Qazvin, Iran.
| | - Hossein Honari
- Faculty of Basic Science, Imam Hussein University, Tehran, Iran
| | - Ramin Hosseini
- Biotechnology Department, Faculty of Agricultural and Natural Sciences, Imam Khomeini International University (IKIU), Qazvin, Iran
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19
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Farhani I, Nezafat N, Mahmoodi S. Designing a Novel Multi-epitope Peptide Vaccine Against Pathogenic Shigella spp. Based Immunoinformatics Approaches. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9698-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Assembly, Biochemical Characterization, Immunogenicity, Adjuvanticity, and Efficacy of Shigella Artificial Invaplex. mSphere 2018; 3:mSphere00583-17. [PMID: 29600284 PMCID: PMC5874444 DOI: 10.1128/msphere.00583-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/02/2018] [Indexed: 11/20/2022] Open
Abstract
The native Invaplex (InvaplexNAT) vaccine and adjuvant is an ion exchange-purified product derived from the water extract of virulent Shigella species. The key component of InvaplexNAT is a high-molecular-mass complex (HMMC) consisting of the Shigella lipopolysaccharide (LPS) and the invasin proteins IpaB and IpaC. To improve product purity and immunogenicity, artificial Invaplex (InvaplexAR) was developed using recombinant IpaB and IpaC proteins and purified Shigella LPS to assemble an HMMC consisting of all three components. Characterization of InvaplexAR by various methods demonstrated similar characteristics as the previously reported HMMC in InvaplexNAT. The well-defined InvaplexAR vaccine consistently contained greater quantities of IpaB, IpaC, and LPS than InvaplexNAT. InvaplexAR and InvaplexNAT immunogenicities were compared in mouse and guinea pig dose escalation studies. In both models, immunization induced antibody responses specific for InvaplexNAT and LPS while InvaplexAR induced markedly higher anti-IpaB and -IpaC serum IgG and IgA endpoint titers. In the murine model, homologous protection was achieved with 10-fold less InvaplexAR than InvaplexNAT and mice receiving InvaplexAR lost significantly less weight than mice receiving the same amount of InvaplexNAT. Moreover, mice immunized with InvaplexAR were protected from challenge with both homologous and heterologous Shigella serotypes. Guinea pigs receiving approximately 5-fold less InvaplexAR compared to cohorts immunized with InvaplexNAT were protected from ocular challenge. Furthermore, adjuvanticity previously attributed to InvaplexNAT was retained with InvaplexAR. The second-generation Shigella Invaplex vaccine, InvaplexAR, offers significant advantages over InvaplexNAT in reproducibility, flexible yet defined composition, immunogenicity, and protective efficacy. IMPORTANCEShigella species are bacteria that cause severe diarrheal disease worldwide, primarily in young children. Treatment of shigellosis includes oral fluids and antibiotics, but the high burden of disease, increasing prevalence of antibiotic resistance, and long-term health consequences clearly warrant the development of an effective vaccine. One Shigella vaccine under development is termed the invasin complex or Invaplex and is designed to drive an immune response to specific antigens of the bacteria in an effort to protect an individual from infection. The work presented here describes the production and evaluation of a new generation of Invaplex. The improved vaccine stimulates the production of antibodies in immunized mice and guinea pigs and protects these animals from Shigella infection. The next step in the product's development will be to test the safety and immune response induced in humans immunized with Invaplex.
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Arabshahi S, Nayeri Fasaei B, Derakhshandeh A, Novinrooz A. In silico design of a novel chimeric shigella IpaB fused to C terminal of clostridium perfringens enterotoxin as a vaccine candidate. Bioengineered 2017; 9:170-177. [PMID: 29091543 PMCID: PMC5972921 DOI: 10.1080/21655979.2017.1373535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This study aimed to design a novel chimeric protein in silico to serve as a serotype-independent vaccine candidate against Shigella. The chimera contains amino acid residues 240–460 of Shigella invasion plasmid antigen B (IpaB) and the C-terminus of Clostridium perfringens enterotoxin (C-CPE). Amino acid sequences of 537 peptide linkers were obtained from two protein linker databases. 3D structures of IpaB-CPE290–319, IpaB-CPE184–319, IpaB-CPE194–319 and 537 newly designed IpaB-linker-CPE290–319 constructs with varying linker regions were predicted. These predicted 3D structures were merged with the 3D structures of native IpaB240–460, CPE194–319, CPE184–319 and CPE290–319 to select the structure most similar to native IpaB and C-CPE. Several in silico tools were used to determine the suitability of the selected IpaB-C-CPE structure as a vaccine candidate. None of the 537 linkers was capable of preserving the native structure of CPE290–319 within the IpaB-linker-CPE290–319 structure. In silico analysis determined that the IpaB-CPE194–319 3D structure was the most similar to the 3D structure of the respective native CPE domain and that it was a stable chimeric protein exposing multiple B-cell epitopes. IpaB-CPE194–319 was designed for its capability to bind to human intestinal epithelial and M cells and to accumulate on these cells. The predicted B-cell epitopes are likely to be capable of inducing a mucosal antibody response in the human intestine against Shigella IpaB. This study also showed that the higher binding affinities of CPE184–319 and CPE194–319 to claudin molecules than those of CPE290–319 is the result of preserving the 3D structures of CPE184–319 and CPE194–319 when they are linked to the C-termini of other proteins.
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Affiliation(s)
- Sina Arabshahi
- a Department of Pathobiology , School of Veterinary Medicine, Shiraz University , Shiraz , Iran
| | - Bahar Nayeri Fasaei
- b Department of Microbiology and Immunology, Faculty of Veterinary Medicine , University of Tehran , Tehran , Iran
| | - Abdollah Derakhshandeh
- a Department of Pathobiology , School of Veterinary Medicine, Shiraz University , Shiraz , Iran
| | - Aytak Novinrooz
- a Department of Pathobiology , School of Veterinary Medicine, Shiraz University , Shiraz , Iran
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Vander Broek CW, Stevens JM. Type III Secretion in the Melioidosis Pathogen Burkholderia pseudomallei. Front Cell Infect Microbiol 2017; 7:255. [PMID: 28664152 PMCID: PMC5471309 DOI: 10.3389/fcimb.2017.00255] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/31/2017] [Indexed: 02/03/2023] Open
Abstract
Burkholderia pseudomallei is a Gram-negative intracellular pathogen and the causative agent of melioidosis, a severe disease of both humans and animals. Melioidosis is an emerging disease which is predicted to be vastly under-reported. Type III Secretion Systems (T3SSs) are critical virulence factors in Gram negative pathogens of plants and animals. The genome of B. pseudomallei encodes three T3SSs. T3SS-1 and -2, of which little is known, are homologous to Hrp2 secretion systems of the plant pathogens Ralstonia and Xanthomonas. T3SS-3 is better characterized and is homologous to the Inv/Mxi-Spa secretion systems of Salmonella spp. and Shigella flexneri, respectively. Upon entry into the host cell, B. pseudomallei requires T3SS-3 for efficient escape from the endosome. T3SS-3 is also required for full virulence in both hamster and murine models of infection. The regulatory cascade which controls T3SS-3 expression and the secretome of T3SS-3 have been described, as well as the effect of mutations of some of the structural proteins. Yet only a few effector proteins have been functionally characterized to date and very little work has been carried out to understand the hierarchy of assembly, secretion and temporal regulation of T3SS-3. This review aims to frame current knowledge of B. pseudomallei T3SSs in the context of other well characterized model T3SSs, particularly those of Salmonella and Shigella.
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Affiliation(s)
- Charles W Vander Broek
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of EdinburghMidlothian, United Kingdom
| | - Joanne M Stevens
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of EdinburghMidlothian, United Kingdom
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Jneid B, Moreau K, Plaisance M, Rouaix A, Dano J, Simon S. Role of T3SS-1 SipD Protein in Protecting Mice against Non-typhoidal Salmonella Typhimurium. PLoS Negl Trop Dis 2016; 10:e0005207. [PMID: 27992422 PMCID: PMC5167260 DOI: 10.1371/journal.pntd.0005207] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/25/2016] [Indexed: 11/24/2022] Open
Abstract
Background Salmonella enterica species are enteric pathogens that cause severe diseases ranging from self-limiting gastroenteritis to enteric fever and sepsis in humans. These infectious diseases are still the major cause of morbidity and mortality in low-income countries, especially in children younger than 5 years and immunocompromised adults. Vaccines targeting typhoidal diseases are already marketed, but none protect against non-typhoidal Salmonella. The existence of multiple non-typhoidal Salmonella serotypes as well as emerging antibiotic resistance highlight the need for development of a broad-spectrum protective vaccine. All Salmonella spp. utilize two type III Secretion Systems (T3SS 1 and 2) to initiate infection, allow replication in phagocytic cells and induce systemic disease. T3SS-1, which is essential to invade epithelial cells and cross the barrier, forms an extracellular needle and syringe necessary to inject effector proteins into the host cell. PrgI and SipD form, respectively, the T3SS-1 needle and the tip complex at the top of the needle. Because they are common and highly conserved in all virulent Salmonella spp., they might be ideal candidate antigens for a subunit-based, broad-spectrum vaccine. Principal Findings We investigated the immunogenicity and protective efficacy of PrgI and SipD administered by subcutaneous, intranasal and oral routes, alone or combined, in a mouse model of Salmonella intestinal challenge. Robust IgG (in all immunization routes) and IgA (in intranasal and oral immunization routes) antibody responses were induced against both proteins, particularly SipD. Mice orally immunized with SipD alone or SipD combined with PrgI were protected against lethal intestinal challenge with Salmonella Typhimurium (100 Lethal Dose 50%) depending on antigen, route and adjuvant. Conclusions and Significance Salmonella T3SS SipD is a promising antigen for the development of a protective Salmonella vaccine, and could be developed for vaccination in tropical endemic areas to control infant mortality. Salmonella are bacteria responsible for a high global burden of invasive diseases, especially in South and South-East Asia (mainly enteric fever due to Salmonella Typhi) and sub-Saharan Africa (mainly invasive Non-Typhoidal Salmonella, iNTS). This iNTS disease has emerged as a prominent cause of systemic infection in children and immunocompromised African adults, with an associated case fatality of 20–25%. Because licensed vaccines only protect against enteric fever, there is a crucial need to develop a new broad-spectrum vaccine effective against enteric fever and iNTS that can be administered safely to children under 2 years old. The virulence of Salmonella depends on two type III secretion systems (T3SS-1 and T3SS-2) necessary for invasion, replication, intracellular survival and dissemination of the bacteria. Two structural proteins of T3SS-1 (essential for crossing the epithelial barrier) are highly conserved among Salmonella spp. and might be good candidates for a broad-spectrum vaccine. The current study describes the protective effect elicited by these proteins in a murine model. A specific immune response was generated against our antigens and provided protection against Salmonella Typhimurium oral infection. Such a candidate vaccine offers promising perspectives to control Salmonella diseases.
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Affiliation(s)
- Bakhos Jneid
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Karine Moreau
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marc Plaisance
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Audrey Rouaix
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Julie Dano
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Stéphanie Simon
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
- * E-mail:
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24
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Development of recombinant vaccine candidate molecule against Shigella infection. Vaccine 2016; 34:5376-5383. [DOI: 10.1016/j.vaccine.2016.08.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 07/28/2016] [Accepted: 08/12/2016] [Indexed: 11/22/2022]
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Circulating Gut-Homing (α4β7+) Plasmablast Responses against Shigella Surface Protein Antigens among Hospitalized Patients with Diarrhea. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2016; 23:610-7. [PMID: 27193041 DOI: 10.1128/cvi.00205-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/09/2016] [Indexed: 11/20/2022]
Abstract
Developing countries are burdened with Shigella diarrhea. Understanding mucosal immune responses associated with natural Shigella infection is important to identify potential correlates of protection and, as such, to design effective vaccines. We performed a comparative analysis of circulating mucosal plasmablasts producing specific antibodies against highly conserved invasive plasmid antigens (IpaC, IpaD20, and IpaD120) and two recently identified surface protein antigens, pan-Shigella surface protein antigen 1 (PSSP1) and PSSP2, common to all virulent Shigella strains. We examined blood and stool specimens from 37 diarrheal patients admitted to the Infectious Diseases & Beliaghata General Hospital, Kolkata, India. The etiological agent of diarrhea was investigated in stool specimens by microbiological methods and real-time PCR. Gut-homing (α4β7 (+)) antibody-secreting cells (ASCs) were isolated from patient blood by means of combined magnetic cell sorting and two-color enzyme-linked immunosorbent spot (ELISPOT) assay. Overall, 57% (21 of 37) and 65% (24 of 37) of the patients were positive for Shigella infection by microbiological and real-time PCR assays, respectively. The frequency of α4β7 (+) IgG ASC responders against Ipas was higher than that observed against PSSP1 or PSSP2, regardless of the Shigella serotype isolated from these patients. Thus, α4β7 (+) ASC responses to Ipas may be considered an indirect marker of Shigella infection. The apparent weakness of ASC responses to PSSP1 is consistent with the lack of cross-protection induced by natural Shigella infection. The finding that ASC responses to IpaD develop in patients with recent-onset shigellosis indicates that such responses may not be protective or may wane too rapidly and/or be of insufficient magnitude.
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Bulir DC, Liang S, Lee A, Chong S, Simms E, Stone C, Kaushic C, Ashkar A, Mahony JB. Immunization with chlamydial type III secretion antigens reduces vaginal shedding and prevents fallopian tube pathology following live C. muridarum challenge. Vaccine 2016; 34:3979-85. [PMID: 27325352 DOI: 10.1016/j.vaccine.2016.06.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/25/2016] [Accepted: 06/14/2016] [Indexed: 11/26/2022]
Abstract
Chlamydia trachomatis infections in women are often asymptomatic and if left untreated can lead to significant late sequelae including pelvic inflammatory disease and tubal factor infertility. Vaccine development efforts over the past three decades have been unproductive and there is no vaccine approved for use in humans. The existence of serologically distinct strains or serovars of C. trachomatis mandates a vaccine that will provide protection against multiple serovars. Chlamydia spp. use a highly conserved type III secretion system (T3SS) composed of both structural and effector proteins which is an essential virulence factor for infection and intracellular replication. In this study we evaluated a novel fusion protein antigen (BD584) which consists of three T3SS proteins from C. trachomatis (CopB, CopD, and CT584) as a potential chlamydial vaccine candidate. Intranasal immunization with BD584 elicited serum neutralizing antibodies that inhibited C. trachomatis infection in vitro. Following intravaginal challenge with C. muridarum, immunized mice had a 95% reduction in chlamydial shedding from the vagina at the peak of infection and cleared the infection sooner than control mice. Immunization with BD584 also reduced the rate of hydrosalpinx by 87.5% compared to control mice. Together, these results suggest that highly conserved proteins of the chlamydial T3SS may represent good candidates for a Chlamydia vaccine.
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Affiliation(s)
- David C Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Steven Liang
- M. G. DeGroote Institute for Infectious Disease Research, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Amanda Lee
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Sylvia Chong
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Elizabeth Simms
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Christopher Stone
- St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada
| | - Charu Kaushic
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - Ali Ashkar
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada
| | - James B Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Canada; Department of Pathology and Molecular Medicine, McMaster University, Canada; St. Joseph's Research Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada.
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27
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Bulir DC, Waltho DA, Stone CB, Liang S, Chiang CKW, Mwawasi KA, Nelson JC, Zhang SW, Mihalco SP, Scinocca ZC, Mahony JB. Chlamydia Outer Protein (Cop) B from Chlamydia pneumoniae possesses characteristic features of a type III secretion (T3S) translocator protein. BMC Microbiol 2015; 15:163. [PMID: 26272448 PMCID: PMC4536800 DOI: 10.1186/s12866-015-0498-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/03/2015] [Indexed: 01/26/2023] Open
Abstract
Background Chlamydia spp. are believed to use a conserved virulence factor called type III secretion (T3S) to facilitate the delivery of effector proteins from the bacterial pathogen to the host cell. Important early effector proteins of the type III secretion system (T3SS) are a class of proteins called the translocators. The translocator proteins insert into the host cell membrane to form a pore, allowing the injectisome to dock onto the host cell to facilitate translocation of effectors. CopB is a predicted hydrophobic translocator protein within the chlamydial T3SS. Results In this study, we identified a novel interaction between the hydrophobic translocator, CopB, and the putative filament protein, CdsF. Furthermore, we identified a conserved PxLxxP motif in CopB (amino acid residues 166–171), which is required for interaction with its cognate chaperone, LcrH_1. Using a synthetic peptide derived from the chaperone binding motif of CopB, we were able to block the LcrH_1 interaction with either CopB or CopD; this CopB peptide was capable of inhibiting C. pneumoniae infection of HeLa cells at micromolar concentrations. An antibody raised against the N-terminus of CopB was able to inhibit C. pneumoniae infection of HeLa cells. Conclusion The inhibition of the LcrH_1:CopB interaction with a cognate peptide and subsequent inhibition of host cell infection provides strong evidence that T3S is an essential virulence factor for chlamydial infection and pathogenesis. Together, these results support that CopB plays the role of a hydrophobic translocator.
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Affiliation(s)
- David C Bulir
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Daniel A Waltho
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Christopher B Stone
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Steven Liang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Christopher K W Chiang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Kenneth A Mwawasi
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Jordan C Nelson
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Steven W Zhang
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Samantha P Mihalco
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - Zachariah C Scinocca
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada.
| | - James B Mahony
- M. G. DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. .,Father Sean O'Sullivan Research Centre, St. Joseph's Healthcare, Hamilton, ON, Canada. .,Regional Virology Laboratory, St. Joseph's Healthcare, 50 Charlton Ave. E, Hamilton, ON, L8N 4A6, Canada.
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Vander Broek CW, Chalmers KJ, Stevens MP, Stevens JM. Quantitative proteomic analysis of Burkholderia pseudomallei Bsa type III secretion system effectors using hypersecreting mutants. Mol Cell Proteomics 2015; 14:905-16. [PMID: 25635268 PMCID: PMC4390269 DOI: 10.1074/mcp.m114.044875] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/07/2015] [Indexed: 11/06/2022] Open
Abstract
Burkholderia pseudomallei is an intracellular pathogen and the causative agent of melioidosis, a severe disease of humans and animals. One of the virulence factors critical for early stages of infection is the Burkholderia secretion apparatus (Bsa) Type 3 Secretion System (T3SS), a molecular syringe that injects bacterial proteins, called effectors, into eukaryotic cells where they subvert cellular functions to the benefit of the bacteria. Although the Bsa T3SS itself is known to be important for invasion, intracellular replication, and virulence, only a few genuine effector proteins have been identified and the complete repertoire of proteins secreted by the system has not yet been fully characterized. We constructed a mutant lacking bsaP, a homolog of the T3SS "gatekeeper" family of proteins that exert control over the timing and magnitude of effector protein secretion. Mutants lacking BsaP, or the T3SS translocon protein BipD, were observed to hypersecrete the known Bsa effector protein BopE, providing evidence of their role in post-translational control of the Bsa T3SS and representing key reagents for the identification of its secreted substrates. Isobaric Tags for Relative and Absolute Quantification (iTRAQ), a gel-free quantitative proteomics technique, was used to compare the secreted protein profiles of the Bsa T3SS hypersecreting mutants of B. pseudomallei with the isogenic parent strain and a bsaZ mutant incapable of effector protein secretion. Our study provides one of the most comprehensive core secretomes of B. pseudomallei described to date and identified 26 putative Bsa-dependent secreted proteins that may be considered candidate effectors. Two of these proteins, BprD and BapA, were validated as novel effector proteins secreted by the Bsa T3SS of B. pseudomallei.
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Affiliation(s)
- Charles W Vander Broek
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Kevin J Chalmers
- §Dundee Cell Products, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, Scotland, UK
| | - Mark P Stevens
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Joanne M Stevens
- From the ‡The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.;
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29
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Heine SJ, Franco-Mahecha OL, Chen X, Choudhari S, Blackwelder WC, van Roosmalen ML, Leenhouts K, Picking WL, Pasetti MF. Shigella IpaB and IpaD displayed on L. lactis bacterium-like particles induce protective immunity in adult and infant mice. Immunol Cell Biol 2015; 93:641-52. [PMID: 25776843 PMCID: PMC4534326 DOI: 10.1038/icb.2015.24] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/28/2015] [Accepted: 01/28/2015] [Indexed: 02/01/2023]
Abstract
Shigella spp. are among the enteric pathogens with the
highest attributable incidence of moderate-to-severe diarrhea in children under
5 years of age living in endemic areas. There are no vaccines available to
prevent this disease. In this work, we investigated a new
Shigella vaccine concept consisting of non-living,
self-adjuvanted, Lactococcus lactis bacterium-like particles
(BLP) displaying Shigella invasion plasmid antigen (Ipa) B and
IpaD and examined its immunogenicity and protective efficacy in adult and
newborn/infant mice immunized via the nasal route. Unique advantages of this
approach include the potential for broad protection due to the highly conserved
structure of the Ipas and the safety and practicality of a probiotic-based
mucosal/adjuvant delivery platform. Immunization of adult mice with BLP-IpaB and
BLP-IpaD (BLP-IpaB/D) induced high levels of Ipa-specific serum IgG and stool
IgA in a dose-dependent manner. Immune responses and protection were enhanced by
BLP delivery. Vaccine-induced serum antibodies exhibited opsonophagocytic and
cytotoxic neutralizing activity, and IpaB/D IgG titers correlated with increased
survival post-challenge. Ipa-specific antibody secreting cells were detected in
nasal tissue and lungs, as well as IgG in bronchoalveolar lavage. Bone marrow
cells produced IpaB/D-specific antibodies and contributed to protection after
adoptive transfer. The BLP-IpaB/D vaccine conferred 90% and 80%
protection against S. flexneri and S. sonnei,
respectively. Mice immunized with BLP-IpaB/D as newborns also developed IpaB and
IpaD serum antibodies; 90% were protected against S.
flexneri and 44% against S. sonnei. The
BLP-IpaB/D vaccine is a promising candidate for safe, practical and potentially
effective immunization of children against shigellosis.
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Affiliation(s)
- Shannon J Heine
- 1] Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA [2] Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Olga L Franco-Mahecha
- 1] Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA [2] Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Xiaotong Chen
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Shyamal Choudhari
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
| | - William C Blackwelder
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | | | - Wendy L Picking
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Marcela F Pasetti
- 1] Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA [2] Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA
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Charro N, Mota LJ. Approaches targeting the type III secretion system to treat or prevent bacterial infections. Expert Opin Drug Discov 2015; 10:373-87. [DOI: 10.1517/17460441.2015.1019860] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Nuno Charro
- 1UCIBIO, REQUIMTE, Departmento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516, Portugal
| | - Luís Jaime Mota
- 2UCIBIO, REQUIMTE, Departmento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516, Portugal ;
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Chitradevi STS, Kaur G, Uppalapati S, Yadav A, Singh D, Bansal A. Co-administration of rIpaB domain of Shigella with rGroEL of S. Typhi enhances the immune responses and protective efficacy against Shigella infection. Cell Mol Immunol 2015; 12:757-67. [PMID: 25640657 DOI: 10.1038/cmi.2014.86] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 08/15/2014] [Accepted: 08/16/2014] [Indexed: 02/07/2023] Open
Abstract
Shigella species cause severe bacillary dysentery in humans and are associated with high morbidity and mortality. The Invasion plasmid antigen (IpaB) protein, which is conserved across all Shigella spp., induces macrophage cell death and is required to invade host cells. The present study evaluates the immunogenicity and protective efficacy of the recombinant (r) domain region of IpaB (rIpaB) of S. flexneri. rIpaB was administered either alone or was co-administered with the rGroEL (heat shock protein 60) protein from S. Typhi as an adjuvant in a mouse model of intranasal immunization. The IpaB domain region (37 kDa) of S. flexneri was amplified from an invasion plasmid, cloned, expressed in BL21 Escherichia coli cells and purified. Immunization with the rIpaB domain alone stimulated both humoral and cell-mediated immune responses. Furthermore, robust antibody (IgG, IgA) and T-cell responses were induced when the rIpaB domain was co-administered with rGroEL. Antibody isotyping revealed higher IgG1 and IgG2a antibody titers and increased interferon-gamma (IFN-γ) secretion in the co-administered group. Immunization of mice with the rIpaB domain alone protected 60%-70% of the mice from lethal infection by S. flexneri, S. boydii and S. sonnei, whereas co-administration with rGroEL increased the protective efficacy to 80%-85%. Organ burden and histopathological studies also revealed a significant reduction in lung infection in the co-immunized mice compared with mice immunized with the rIpaB domain alone. This study emphasizes that the co-administration of the rIpaB domain and rGroEL protein improves immune responses in mice and increases protective efficacy against Shigella infection. This is also the first report to evaluate the potential of the GroEL (Hsp 60) protein of S. Typhi as an adjuvant molecule, thereby overcoming the need for commercial adjuvants.
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Affiliation(s)
| | - Gurpreet Kaur
- Division of Experimental Biology, Defence Institute of Physiology and Allied Sciences, Delhi, India
| | | | - Anandprakash Yadav
- Division of Immunomodulation, Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Dependrapratap Singh
- Division of Experimental Biology, Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Anju Bansal
- Division of Experimental Biology, Defence Institute of Physiology and Allied Sciences, Delhi, India
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The immune response of two microbial antigens delivered intradermally, sublingually, or the combination thereof. Microbes Infect 2014; 16:796-803. [PMID: 25111827 DOI: 10.1016/j.micinf.2014.07.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/07/2014] [Accepted: 07/29/2014] [Indexed: 11/21/2022]
Abstract
A key consideration to produce a successful vaccine is the choice of appropriate vaccination route. Though most vaccines are administered parenterally, this route is not effective in producing a robust mucosal or cell-mediated response. Intradermal and sublingual vaccinations have been explored recently as potential needle-free immunization strategies. We explored intradermal and sublingual routes as well as the combination of the two routes in eliciting both systemic and mucosal immune responses. Mice were immunized intradermally or sublingually with dmLT, a mutant of Escherichia coli heat-labile toxin. A systemic IgG response is dominant in intradermal immunization while a mucosal IgA response is dominant in sublingual immunization. When routes were combined, a synergistic response was seen with high titers of anti-dmLT IgG and IgA. IpaB/IpaD antigens of Shigella flexneri type III secretion system, were admixed with dmLT as adjuvant and administered by each route alone or in combination. Again, the intradermal route elicited a systemic response while the sublingual route elicited a mucosal response. When combined, the routes produced a robust synergistic response to both antigens that exhibited a balanced Th1/Th2 response. These results provide a new potential needle-free immunization strategy that will benefit low income countries and increase compliance in industrial countries.
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Heine SJ, Diaz-McNair J, Andar AU, Drachenberg CB, van de Verg L, Walker R, Picking WL, Pasetti MF. Intradermal delivery of Shigella IpaB and IpaD type III secretion proteins: kinetics of cell recruitment and antigen uptake, mucosal and systemic immunity, and protection across serotypes. THE JOURNAL OF IMMUNOLOGY 2014; 192:1630-40. [PMID: 24453241 DOI: 10.4049/jimmunol.1302743] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Shigella is one of the leading pathogens contributing to the vast pediatric diarrheal disease burden in low-income countries. No licensed vaccine is available, and the existing candidates are only partially effective and serotype specific. Shigella type III secretion system proteins IpaB and IpaD, which are conserved across Shigella spp., are candidates for a broadly protective, subunit-based vaccine. In this study, we investigated the immunogenicity and protective efficacy of IpaB and IpaD administered intradermally (i.d.) with a double-mutant of the Escherichia coli heat-labile enterotoxin (dmLT) adjuvant using microneedles. Different dosage levels of IpaB and IpaD, with or without dmLT, were tested in mice. Vaccine delivery into the dermis, recruitment of neutrophils, macrophages, dendritic cells, and Langerhans cells, and colocalization of vaccine Ag within skin-activated APC were demonstrated through histology and immunofluorescence microscopy. Ag-loaded neutrophils, macrophages, dendritic cells, and Langerhans cells remained in the tissue at least 1 wk. IpaB, IpaD, and dmLT-specific serum IgG- and IgG-secreting cells were produced following i.d. immunization. The protective efficacy was 70% against Shigella flexneri and 50% against Shigella sonnei. Similar results were obtained when the vaccine was administered intranasally, with the i.d. route requiring 25-40 times lower doses. Distinctively, IgG was detected in mucosal secretions; secretory IgA, as well as mucosal and systemic IgA Ab-secreting cells, were seemingly absent. Vaccine-induced T cells produced IFN-γ, IL-2, TNF-α, IL-17, IL-4, IL-5, and IL-10. These results demonstrate the potential of i.d. vaccination with IpaB and IpaD to prevent Shigella infection and support further studies in humans.
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Affiliation(s)
- Shannon J Heine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201
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Marshall NC, Finlay BB. Targeting the type III secretion system to treat bacterial infections. Expert Opin Ther Targets 2013; 18:137-52. [DOI: 10.1517/14728222.2014.855199] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Characterization of a novel fusion protein from IpaB and IpaD of Shigella spp. and its potential as a pan-Shigella vaccine. Infect Immun 2013; 81:4470-7. [PMID: 24060976 DOI: 10.1128/iai.00859-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigellosis is an important disease in the developing world, where about 90 million people become infected with Shigella spp. each year. We previously demonstrated that the type three secretion apparatus (T3SA) proteins IpaB and IpaD are protective antigens in the mouse lethal pulmonary model. In order to simplify vaccine formulation and process development, we have evaluated a vaccine design that incorporates both of these previously tested Shigella antigens into a single polypeptide chain. To determine if this fusion protein (DB fusion) retains the antigenic and protective capacities of IpaB and IpaD, we immunized mice with the DB fusion and compared the immune response to that elicited by the IpaB/IpaD combination vaccine. Purification of the DB fusion required coexpression with IpgC, the IpaB chaperone, and after purification it maintained the highly α-helical characteristics of IpaB and IpaD. The DB fusion also induced comparable immune responses and retained the ability to protect mice against Shigella flexneri and S. sonnei in the lethal pulmonary challenge. It also offered limited protection against S. dysenteriae challenge. Our results show the feasibility of generating a protective Shigella vaccine comprised of the DB fusion.
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Ashkenazi S, Cohen D. An update on vaccines against Shigella. THERAPEUTIC ADVANCES IN VACCINES 2013; 1:113-23. [PMID: 24757519 PMCID: PMC3967666 DOI: 10.1177/2051013613500428] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Despite intensive research efforts for more than 60 years, utilizing diverse vaccine strategies, a safe and efficacious vaccine against shigellosis is not available yet. We are currently witnessing innovative approaches based on elucidation of the virulence mechanisms of Shigella, understanding the immune response to the pathogen and progress in molecular technology for developing Shigella vaccines. It is hoped that these will lead to a licensed effective Shigella vaccine to protect humans against the significant worldwide morbidity and mortality caused by this microorganism.
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Affiliation(s)
- Shai Ashkenazi
- Department of Pediatrics A, Schneider Children's Medical Center, 14 Kaplan Street, Petach Tikva 49202, Israel
| | - Dani Cohen
- School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Israel
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