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Boerth EM, Gong J, Roffler B, Hancock Z, Berger L, Song B, Malley SF, MacLennan CA, Zhang F, Malley R, Lu YJ. Evaluation of a Quadrivalent Shigella flexneri Serotype 2a, 3a, 6, and Shigella sonnei O-Specific Polysaccharide and IpaB MAPS Vaccine. Vaccines (Basel) 2024; 12:1091. [PMID: 39460258 PMCID: PMC11510904 DOI: 10.3390/vaccines12101091] [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: 08/01/2024] [Revised: 09/05/2024] [Accepted: 09/20/2024] [Indexed: 10/28/2024] Open
Abstract
BACKGROUND Shigellosis is the leading cause of diarrheal deaths worldwide and is particularly dangerous in children under 5 years of age in low- and middle-income countries. Additionally, the rise in antibiotic resistance has highlighted the need for an effective Shigella vaccine. Previously, we have used the Multiple Antigen-Presenting System (MAPS) technology to generate monovalent and quadrivalent Salmonella MAPS vaccines that induce functional antibodies against Salmonella components. METHODS In this work, we detail the development of several monovalent vaccines using O-specific polysaccharides (OSPs) from four dominant serotypes, S. flexneri 2a, 3a, and 6, and S. sonnei. We tested several rhizavidin (rhavi) fusion proteins and selected a Shigella-specific protein IpaB. Quadrivalent MAPS were made with Rhavi-IpaB protein and tested in rabbits for immunogenicity. RESULTS Individual MAPS vaccines generated robust, functional antibody responses against both IpaB and the individual OSP component. Antibodies to IpaB were effective across Shigella serotypes. We also demonstrate that the OSP antibodies generated are specific to each homologous Shigella O type by performing ELISA and bactericidal assays. We combined the components of each MAPS vaccine to formulate a quadrivalent MAPS vaccine which elicited similar antibody and bactericidal responses compared to their monovalent counterparts. Finally, we show that the quadrivalent MAPS immune sera are functional against several clinical isolates of the serotypes used in the vaccine. CONCLUSIONS This quadrivalent MAPS Shigella vaccine is immunogenicity and warrants further study.
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Affiliation(s)
- Emily M. Boerth
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Joyce Gong
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Becky Roffler
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Zoe Hancock
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lydia Berger
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Boni Song
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sasha F. Malley
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Calman A. MacLennan
- Enteric & Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, 500 5th Ave. N, Seattle, WA 98109, USA
| | - Fan Zhang
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Richard Malley
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ying-Jie Lu
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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Benedicto-Matambo P, Avolio LN, Badji H, Batool R, Khanam F, Munga S, Tapia MD, Peñataro Yori P, Awuor AO, Ceesay BE, Cornick J, Cunliffe NA, Garcia Bardales PF, Heaney CD, Hotwani A, Ireen M, Taufiqul Islam M, Jallow O, Kaminski RW, Shapiama Lopez WV, Maiden V, Ikumapayi UN, Nyirenda R, Ochieng JB, Omore R, Paredes Olortegui M, Pavlinac PB, Pisanic N, Qadri F, Qureshi S, Rahman N, Rogawski McQuade ET, Schiaffino F, Secka O, Sonye C, Sultana S, Timite D, Traore A, Yousafzai MT, Taufiqur Rahman Bhuiyan M, Jahangir Hossain M, Jere KC, Kosek MN, Kotloff KL, Qamar FN, Sow SO, Platts-Mills JA. Exploring Natural Immune Responses to Shigella Exposure Using Multiplex Bead Assays on Dried Blood Spots in High-Burden Countries: Protocol From a Multisite Diarrhea Surveillance Study. Open Forum Infect Dis 2024; 11:S58-S64. [PMID: 38532958 PMCID: PMC10962721 DOI: 10.1093/ofid/ofad650] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024] Open
Abstract
Background Molecular diagnostics on human fecal samples have identified a larger burden of shigellosis than previously appreciated by culture. Evidence of fold changes in immunoglobulin G (IgG) to conserved and type-specific Shigella antigens could be used to validate the molecular assignment of type-specific Shigella as the etiology of acute diarrhea and support polymerase chain reaction (PCR)-based microbiologic end points for vaccine trials. Methods We will test dried blood spots collected at enrollment and 4 weeks later using bead-based immunoassays for IgG to invasion plasmid antigen B and type-specific lipopolysaccharide O-antigen for Shigella flexneri 1b, 2a, 3a, and 6 and Shigella sonnei in Shigella-positive cases and age-, site-, and season-matched test-negative controls from all sites in the Enterics for Global Health (EFGH) Shigella surveillance study. Fold antibody responses will be compared between culture-positive, culture-negative but PCR-attributable, and PCR-positive but not attributable cases and test-negative controls. Age- and site-specific seroprevalence distributions will be identified, and the association between baseline antibodies and Shigella attribution will be estimated. Conclusions The integration of these assays into the EFGH study will help support PCR-based attribution of acute diarrhea to type-specific Shigella, describe the baseline seroprevalence of conserved and type-specific Shigella antibodies, and support correlates of protection for immunity to Shigella diarrhea. These insights can help support the development and evaluation of Shigella vaccine candidates.
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Affiliation(s)
- Prisca Benedicto-Matambo
- School of Biomedical Sciences and Health Professions, Department of Medical Laboratory Sciences, Kamuzu University of Health Sciences, Blantyre, Malawi
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, UK
| | - Lindsay N Avolio
- Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Henry Badji
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Rabab Batool
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Farhana Khanam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Stephen Munga
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Milagritos D Tapia
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pablo Peñataro Yori
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Alex O Awuor
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Bubacarr E Ceesay
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jennifer Cornick
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, UK
| | - Nigel A Cunliffe
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, UK
| | | | - Christopher D Heaney
- Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Aneeta Hotwani
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Mahzabeen Ireen
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Md Taufiqul Islam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Ousman Jallow
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | | | | | - Victor Maiden
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - Usman Nurudeen Ikumapayi
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Ruth Nyirenda
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
| | - John Benjamin Ochieng
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Richard Omore
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | | | - Patricia B Pavlinac
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Nora Pisanic
- Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Sonia Qureshi
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Nazia Rahman
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Francesca Schiaffino
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
- Faculty of Veterinary Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Ousman Secka
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Catherine Sonye
- Kenya Medical Research Institute, Center for Global Health Research (KEMRI-CGHR), Kisumu, Kenya
| | - Shazia Sultana
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Drissa Timite
- Centre pour le Développement des Vaccins du Mali, Bamako, Mali
| | - Awa Traore
- Centre pour le Développement des Vaccins du Mali, Bamako, Mali
| | | | - Md Taufiqur Rahman Bhuiyan
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - M Jahangir Hossain
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Khuzwayo C Jere
- Malawi Liverpool Wellcome Programme, Blantyre, Malawi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, UK
- School of Life Sciences & Health Professions, Department of Medical Laboratory Sciences, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Margaret N Kosek
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
| | - Karen L Kotloff
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Samba O Sow
- Centre pour le Développement des Vaccins du Mali, Bamako, Mali
| | - James A Platts-Mills
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, USA
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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: 2] [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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From Concept to Clinical Product: A Brief History of the Novel Shigella Invaplex Vaccine’s Refinement and Evolution. Vaccines (Basel) 2022; 10:vaccines10040548. [PMID: 35455297 PMCID: PMC9025769 DOI: 10.3390/vaccines10040548] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/12/2022] [Accepted: 03/23/2022] [Indexed: 01/13/2023] Open
Abstract
The Shigella invasin complex or Invaplex vaccine is a unique subunit approach to generate a protective immune response. Invaplex is a large, macromolecular complex consisting of the major Shigella antigens: lipopolysaccharide (LPS) and the invasion plasmid antigen (Ipa) proteins B and C. Over the past several decades, the vaccine has progressed from initial observations through pre-clinical studies to cGMP manufacture and clinical evaluations. The Invaplex product maintains unique biological properties associated with the invasiveness of virulent shigellae and also presents both serotype-specific epitopes, as well as highly conserved invasin protein epitopes, to the immunized host. The vaccine product has evolved from a native product isolated from wild-type shigellae (native Invaplex) to a more defined vaccine produced from purified LPS and recombinant IpaB and IpaC (artificial Invaplex). Each successive “generation” of the vaccine is derived from earlier versions, resulting in improved immunogenicity, homogeneity and effectiveness. The current vaccine, detoxified artificial Invaplex (InvaplexAR-Detox), was developed for parenteral administration by incorporating LPS with under-acylated lipid A. InvaplexAR-Detox has demonstrated an excellent safety and immunogenicity profile in initial clinical studies and is advancing toward evaluations in the target populations of children and travelers to endemic countries.
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Abstract
Enteric viral and bacterial infections continue to be a leading cause of mortality and morbidity in young children in low-income and middle-income countries, the elderly, and immunocompromised individuals. Vaccines are considered an effective and practical preventive approach against the predominantly fecal-to-oral transmitted gastroenteritis particularly in the resource-limited countries or regions where implementation of sanitation systems and supply of safe drinking water are not quickly achievable. While vaccines are available for a few enteric pathogens including rotavirus and cholera, there are no vaccines licensed for many other enteric viral and bacterial pathogens. Challenges in enteric vaccine development include immunological heterogeneity among pathogen strains or isolates, a lack of animal challenge models to evaluate vaccine candidacy, undefined host immune correlates to protection, and a low protective efficacy among young children in endemic regions. In this article, we briefly updated the progress and challenges in vaccines and vaccine development for the leading enteric viral and bacterial pathogens including rotavirus, human calicivirus, Shigella, enterotoxigenic Escherichia coli (ETEC), cholera, nontyphoidal Salmonella, and Campylobacter, and introduced a novel epitope- and structure-based vaccinology platform known as MEFA (multiepitope fusion antigen) and the application of MEFA for developing broadly protective multivalent vaccines against heterogenous pathogens.
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Affiliation(s)
- Hyesuk Seo
- University of Illinois at Urbana-Champaign, Department of Pathobiology, Urbana, Illinois, USA
| | - Qiangde Duan
- University of Yangzhou, Institute of Comparative Medicine, Yangzhou, PR China
| | - Weiping Zhang
- University of Illinois at Urbana-Champaign, Department of Pathobiology, Urbana, Illinois, USA,CONTACT Weiping Zhang, University of Illinois at Urbana-Champaign, Department of Pathobiology, Urbana, Illinois, USA
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Functional and Antigen-Specific Serum Antibody Levels as Correlates of Protection against Shigellosis in a Controlled Human Challenge Study. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00412-16. [PMID: 27927680 PMCID: PMC5299116 DOI: 10.1128/cvi.00412-16] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/29/2016] [Indexed: 11/29/2022]
Abstract
Shigella is an important cause of diarrheal disease in young children living in developing countries. No approved vaccines are available, and the development of vaccine candidates has been hindered by the lack of firm immunological correlates of protection, among other reasons. To address this gap in knowledge, we established quantitative assays to measure Shigella-specific serum bactericidal antibody (SBA) and opsonophagocytic killing antibody (OPKA) activities and investigated their potential association with protection against disease in humans. SBA, OPKA, and Ipa-, VirG (IscA)-, and Shigella flexneri 2a lipopolysaccharide-specific serum IgG titers were determined in adult volunteers who received Shigella vaccine candidate EcSf2a-2 and in unvaccinated controls, all of whom were challenged with virulent Shigella flexneri 2a. Prechallenge antibody titers were compared with disease severity after challenge. SBA and OPKA, as well as IpaB- and VirG-specific IgG, significantly correlated with reduced illness. SBA and OPKA assays were also used to evaluate the immunogenicity of leading live attenuated vaccine candidates Shigella CVD 1204 and CVD 1208S in humans. A single oral immunization with CVD 1204 or CVD 1208S resulted in SBA seroconversion rates of 71% and 47% and OPKA seroconversion rates of 57% and 35%, respectively. Higher functional antibody responses were induced by CVD 1204, which is consistent with its lower attenuation. This is the first demonstration of SBA, OPKA, and IpaB- and VirG-specific IgG levels as potential serological correlates of protection against shigellosis in humans. These results warrant further studies to establish their capacity to predict protective immunity and vaccine efficacy.
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Li Q, Hu Y, Xu Y, Chen J, Fang L, Liu Z, Jiao X. A gene knock-in method used to purify plasmid pSPI12 from Salmonella enterica serovar Pullorum and characterization of IpaJ. J Microbiol Methods 2014; 98:128-33. [DOI: 10.1016/j.mimet.2014.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 01/16/2014] [Accepted: 01/16/2014] [Indexed: 11/30/2022]
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Camacho AI, Irache JM, Gamazo C. Recent progress towards development of a Shigella vaccine. Expert Rev Vaccines 2013; 12:43-55. [PMID: 23256738 DOI: 10.1586/erv.12.135] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The burden of dysentery due to shigellosis among children in the developing world is still a major concern. A safe and efficacious vaccine against this disease is a priority, since no licensed vaccine is available. This review provides an update of vaccine achievements focusing on subunit vaccine strategies and the forthcoming strategies surrounding this approach. In particular, this review explores several aspects of the pathogenesis of shigellosis and the elicited immune response as being the basis of vaccine requirements. The use of appropriate Shigella antigens, together with the right adjuvants, may offer safety, efficacy and more convenient delivery methods for massive worldwide vaccination campaigns.
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Mitra S, Barman S, Nag D, Sinha R, Saha DR, Koley H. Outer membrane vesicles ofShigella boydiitype 4 induce passive immunity in neonatal mice. ACTA ACUST UNITED AC 2012; 66:240-50. [DOI: 10.1111/j.1574-695x.2012.01004.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/22/2012] [Accepted: 06/22/2012] [Indexed: 11/28/2022]
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Camacho AI, de Souza J, Sánchez-Gómez S, Pardo-Ros M, Irache JM, Gamazo C. Mucosal immunization with Shigella flexneri outer membrane vesicles induced protection in mice. Vaccine 2011; 29:8222-9. [PMID: 21911022 DOI: 10.1016/j.vaccine.2011.08.121] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/25/2011] [Accepted: 08/30/2011] [Indexed: 12/24/2022]
Abstract
Vaccination appears to be the only rational prophylactic approach to control shigellosis. Unfortunately, there is still no safe and efficacious vaccine available. We investigated the protection conferred by a new vaccine containing outer membrane vesicles (OMVs) from Shigella flexneri with an adjuvant based on nanoparticles in an experimental model of shigellosis in mice. OMVs were encapsulated in poly(anhydride) nanoparticles prepared by a solvent displacement method with the copolymer PMV/MA. OMVs loaded into NPs (NP-OMVs) were homogeneous and spherical in shape, with a size of 197nm (PdI=0.06). BALB/c mice (females, 9-week-old, 20±1g) were immunized by intradermal, nasal, ocular (20μg) or oral route (100μg) with free or encapsulated OMV. Thirty-five days after administration, mice were infected intranasally with a lethal dose of S. flexneri (1×10(7)CFU). The new vaccine was able to protect fully against infection when it was administered via mucosa. By intradermal route the NP-OMVs formulation increased the protection from 20%, obtained with free extract, to 100%. Interestingly, both OMVs and OMV-NP induced full protection when administered by the nasal and conjuntival route. A strong association between the ratio of IL-12p40/IL-10 and protection was found. Moreover, low levels of IFN-γ correlate with protection. Under the experimental conditions used, the adjuvant did not induce any adverse effects. These results place OMVs among promising candidates to be used for vaccination against Shigellosis.
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Affiliation(s)
- A I Camacho
- Department of Microbiology, University of Navarra, 31008 Pamplona, Spain
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Shigella sonnei vaccine candidates WRSs2 and WRSs3 are as immunogenic as WRSS1, a clinically tested vaccine candidate, in a primate model of infection. Vaccine 2011; 29:6371-8. [DOI: 10.1016/j.vaccine.2011.04.115] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 04/28/2011] [Indexed: 01/24/2023]
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Tribble D, Kaminski R, Cantrell J, Nelson M, Porter C, Baqar S, Williams C, Arora R, Saunders J, Ananthakrishnan M, Sanders J, Zaucha G, Turbyfill R, Oaks E. Safety and immunogenicity of a Shigella flexneri 2a Invaplex 50 intranasal vaccine in adult volunteers. Vaccine 2010; 28:6076-85. [PMID: 20619378 DOI: 10.1016/j.vaccine.2010.06.086] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/18/2010] [Accepted: 06/25/2010] [Indexed: 02/03/2023]
Abstract
Shigellosis is a leading cause of diarrhea worldwide prompting vaccine development. The Shigella flexneri Invaplex 50 is a macromolecular complex containing IpaB, IpaC, and LPS, formulated from an aqueous extract of virulent Shigella delivered via nasal administration. Preclinical vaccine testing demonstrated safety, immunogenicity and efficacy. An open-label dose-escalating phase 1 study evaluated a 3-dose (2-week intervals) regimen via nasal pipette delivery. Thirty-two subjects were enrolled into one of four vaccine dose groups (10, 50, 240, or 480 microg). The vaccine was well tolerated with minor short-lived nasal symptoms without evidence of dose effect. Antibody-secreting cell (ASC) responses were elicited at doses > or =50 microg with the highest IgG ASC, Invaplex 50 (100%) and S. flexneri 2a LPS (71%), as well as, serologic responses (43%) occurring with the 240 microg dose. Fecal IgA responses, Invaplex 50 (38.5%) and LPS (30.8%), were observed at doses > or =240 microg. The Invaplex 50 nasal vaccine was safe with encouraging mucosal immune responses. Follow-on studies will optimize dose, delivery mechanism and assess efficacy in a S. flexneri 2a challenge study.
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Affiliation(s)
- D Tribble
- Naval Medical Research Center, Silver Spring, MD, USA.
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Kaminski RW, Oaks EV. Inactivated and subunit vaccines to prevent shigellosis. Expert Rev Vaccines 2010; 8:1693-704. [PMID: 19943764 DOI: 10.1586/erv.09.127] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Shigellosis remains a formidable disease globally, with children of the developing world bearing the greatest number of infections. The need for an affordable, safe and efficacious vaccine has persisted for decades. Vaccines to prevent shigellosis can be divided into living and nonliving approaches. Several nonliving Shigella vaccines are currently at different stages of development and show substantial promise. Outlined here is an overview of multiple nonliving vaccine technologies, highlighting their current status and recent advances in testing. In addition, gaps in the knowledge base regarding immune mechanisms of protection are explored.
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Affiliation(s)
- Robert W Kaminski
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
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Immunogenicity and efficacy of highly purified invasin complex vaccine from Shigella flexneri 2a. Vaccine 2008; 26:1353-64. [PMID: 18276045 DOI: 10.1016/j.vaccine.2007.12.040] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 12/13/2007] [Accepted: 12/19/2007] [Indexed: 11/20/2022]
Abstract
Development of a subunit vaccine for shigellosis requires identification of protective antigens and delivering these antigens in a manner that stimulates immunity comparable to that induced by natural infection. The Shigella invasin complex (Invaplex) vaccine is an ion-exchange-purified extract from virulent Shigella that consists of LPS and several other proteins, including the invasins IpaB and IpaC. Intranasal delivery of Invaplex stimulates protective immunity in small animal models for shigellosis. To identify the active component(s) of Invaplex responsible for its immunogenicity and efficacy, size-exclusion chromatography (SEC) was used to separate Invaplex into several different fractions. A high-molecular mass complex with a molecular mass between 669 MDa and 2 MDa consisted primarily of LPS, IpaB and IpaC and was considered to be a highly purified (HP) form of Invaplex. Using the mouse lung model to evaluate the immunogenicity and efficacy of the SEC fractions it was clearly demonstrated that the high-molecular mass complex of the invasins and LPS was responsible for the protective capacity of parent native Invaplex. Other smaller mass SEC fractions were mostly non-immunogenic and did not stimulate solid protection. In guinea pigs, the HP Invaplex stimulated an enhanced immune response as compared to the parent Invaplex and was fully protective. Isolation and characterization of the immunogenic and protective moiety within Invaplex will allow better standardization of the Invaplex product and may allow future development of an Invaplex assembled from purified components.
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Jennison AV, Raqib R, Verma NK. Immunoproteome analysis of soluble and membrane proteins of Shigella flexneri 2457T. World J Gastroenterol 2006; 12:6683-8. [PMID: 17075984 PMCID: PMC4125676 DOI: 10.3748/wjg.v12.i41.6683] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/12/2006] [Accepted: 09/21/2006] [Indexed: 02/06/2023] Open
Abstract
AIM To profile the immunogenic proteins of Shigella flexneri (S. flexneri) expressed during human infection using a proteomic approach. METHODS Soluble and membrane protein extractions of S. flexneri 2457T were separated by two-dimensional gel electrophoresis (2-DE). Proteins were transferred to PVDF membrane and immunoblotted with sera from shigellosis patients. Reactive protein spots were matched to Coomassie stained gels run in parallel, cut out and trypsin digested. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS) was used to determine the peptide mass fingerprints, which were searched in the MASCOT database to identify the protein. RESULTS A total of 8 immunoreactive proteins were successfully identified from the Coomassie stained gels in three repeats. Six of these proteins have not previously been reported as immunogenic in S. flexneri. These proteins could be potential candidates for vaccine or attenuation studies. CONCLUSION Soluble and membrane proteins of S. flexneri 2457T have been screened by 2-DE and immunoblotting with sera from shigellosis patients. Eight proteins are identified as immunogenic.
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Affiliation(s)
- Amy V Jennison
- School of Biochemistry and Molecular Biology, Faculty of Science, The Australian National University, Canberra, ACT 0200, Australia
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Oaks EV, Turbyfill KR. Development and evaluation of a Shigella flexneri 2a and S. sonnei bivalent invasin complex (Invaplex) vaccine. Vaccine 2005; 24:2290-301. [PMID: 16364513 DOI: 10.1016/j.vaccine.2005.11.040] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 10/24/2005] [Accepted: 11/18/2005] [Indexed: 11/19/2022]
Abstract
Over 160 million cases of shigellosis occur annually worldwide, with the two most prevalent species being Shigella flexneri and S. sonnei. Protective immunity against Shigella infection is primarily directed at the lipopolysaccharide (LPS) of the homologous serotype, so it may be necessary to combine monovalent vaccines for multiple Shigella serotypes to construct a multivalent vaccine against predominant serotypes. Recently, we described a subcellular vaccine isolated from virulent S. flexneri, consisting of proteins (including the invasins IpaB and IpaC) and LPS, that protected mice and guinea pigs from homologous challenge. In the present study, a bivalent Invaplex vaccine consisting of S. flexneri 2a and S. sonnei Invaplex was used to intranasally immunize mice and guinea pigs to determine the bivalent vaccine's immunogenicity and protective capacity against challenge with either strain. Mice and guinea pigs immunized with the bivalent S. flexneri 2a/S. sonnei Invaplex vaccine produced serum IgA and IgG antibodies to S. flexneri LPS, S. sonnei LPS, the homologous Invaplex and the water extract antigens (invasins) as determined by ELISA. The immune responses in animals immunized with the bivalent vaccine were similar to responses in animals immunized with the monovalent Invaplex vaccines. Mice and guinea pigs immunized with the bivalent vaccine were protected from a lethal lung challenge (mice, P<0.001) or severe keratoconjunctivitis (guinea pigs, P< or = 0.002) after challenge with either S. flexneri 2a or S. sonnei. Animals immunized with monovalent Invaplex vaccines were protected (P<0.001) against the homologous agent at levels comparable to the bivalent vaccine. After challenge, immunized animals demonstrated boosts in antibody titers to LPS, water extract antigens and Invaplex. These studies indicate that the subcellular Invaplex vaccine will be readily adaptable to a multivalent vaccine approach for shigellosis.
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Affiliation(s)
- Edwin V Oaks
- Walter Reed Army Institute of Research, Silver Spring, MD 20910-7510, USA.
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Thirumalapura NR, Morton RJ, Ramachandran A, Malayer JR. Lipopolysaccharide microarrays for the detection of antibodies. J Immunol Methods 2005; 298:73-81. [PMID: 15847798 DOI: 10.1016/j.jim.2005.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Revised: 11/22/2004] [Accepted: 01/06/2005] [Indexed: 10/25/2022]
Abstract
Lipopolysaccharide (LPS) is the major component of Gram-negative bacterial outer membrane. LPS are immunogenic and show species/strain specificity. The demonstration of anti-LPS antibodies in clinical samples is of diagnostic value in certain Gram-negative bacterial infections. In the present study we explored the possibility of immobilizing LPS isolated from different bacteria in a microarray format for the detection of anti-LPS antibodies. LPS was successfully immobilized on nitrocellulose-coated glass slides, preserving the accessibility of epitopes for antibody binding. Specificity of the LPS arrays was established using four different monoclonal antibodies specific for Escherichia coli O111, E. coli O157, Francisella tularensis and Salmonella typhimurium O-antigens and a panel of LPS preparations. The detection limit of antibodies was found to be 10 ng/ml, which is about a 100-fold greater sensitivity compared to conventional immunofluorescence assays. Furthermore, using LPS arrays, tularemia positive canine serum samples could be differentiated from negative samples based on the presence of significantly higher levels of anti-F. tularensis LPS antibodies in positive samples. LPS arrays will facilitate simultaneous screening of samples against multiple antigens and are expected to find applications in diagnostics and seroepidemiology.
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Affiliation(s)
- N R Thirumalapura
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
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18
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Turbyfill KR, Hartman AB, Oaks EV. Isolation and characterization of a Shigella flexneri invasin complex subunit vaccine. Infect Immun 2000; 68:6624-32. [PMID: 11083774 PMCID: PMC97759 DOI: 10.1128/iai.68.12.6624-6632.2000] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The invasiveness and virulence of Shigella spp. are largely due to the expression of plasmid-encoded virulence factors, among which are the invasion plasmid antigens (Ipa proteins). After infection, the host immune response is directed primarily against lipopolysaccharide (LPS) and the virulence proteins (IpaB, IpaC, and IpaD). Recent observations have indicated that the Ipa proteins (IpaB, IpaC, and possibly IpaD) form a multiprotein complex capable of inducing the phagocytic event which internalizes the bacterium. We have isolated a complex of invasins and LPS from water-extractable antigens of virulent shigellae by ion-exchange chromatography. Western blot analysis of the complex indicates that all of the major virulence antigens of Shigella, including IpaB, IpaC, and IpaD, and LPS are components of this macromolecular complex. Mice or guinea pigs immunized intranasally with purified invasin complex (invaplex), without any additional adjuvant, mounted a significant immunoglobulin G (IgG) and IgA antibody response against the Shigella virulence antigens and LPS. The virulence-specific response was very similar to that previously noted in primates infected with shigellae. Guinea pigs (keratoconjunctivitis model) or mice (lethal lung model) immunized intranasally on days 0, 14, and 28 and challenged 3 weeks later with virulent shigellae were protected from disease (P<0.01 for both animal models).
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Affiliation(s)
- K R Turbyfill
- Department of Enteric Infections, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910-7500, USA
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Turbyfill KR, Mertz JA, Mallett CP, Oaks EV. Identification of epitope and surface-exposed domains of Shigella flexneri invasion plasmid antigen D (IpaD). Infect Immun 1998; 66:1999-2006. [PMID: 9573082 PMCID: PMC108156 DOI: 10.1128/iai.66.5.1999-2006.1998] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transport and surface expression of the invasion plasmid antigens (Ipa proteins) is an essential trait in the pathogenicity of Shigella spp. In addition to the type III protein secretion system encoded by the mxi/spa loci on the large virulence plasmid, transport of IpaB and IpaC into the surrounding medium is modulated by IpaD. To characterize the structural topography of IpaD, the Geysen epitope-mapping system was used to identify epitopes recognized by surface-reactive monoclonal and polyclonal antibodies produced against purified recombinant IpaD or synthetic IpaD peptides. Surface-exposed epitopes of IpaD were confined to the first 180 amino acid residues, whereas epitopes in the carboxyl-terminal half were not exposed on the Shigella surface. By using convalescent-phase sera from 10 Shigella flexneri-infected monkeys, numerous epitopes were mapped within a surface-exposed region of IpaD between amino acid residues 14 and 77. Epitopes were also identified in the carboxyl-terminal half of IpaD with a few convalescent-phase sera. Comparison of IpaD epitope sequences with Salmonella SipD sequences indicated that very similar epitopes may exist in the carboxyl-terminal region of each protein whereas the IpaD epitopes in the surface-exposed amino-terminal region were unique for the Shigella protein. Although the IpaD and SipD homologs may play similar roles in transport, the dominant serum antibody response to IpaD is against the unique region of this protein exposed on the surface of the pathogen.
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Affiliation(s)
- K R Turbyfill
- Department of Enteric Infections, Walter Reed Army Institute of Research, Washington, DC 20307, USA
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Buysse JM, Dunyak DS, Hartman AB, Venkatesan MM. Identification and molecular characterization of a 27 kDa Shigella flexneri invasion plasmid antigen, IpaJ. Microb Pathog 1997; 23:357-69. [PMID: 9441862 DOI: 10.1006/mpat.1997.0164] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Shigella species and enteroinvasive Escherichia coli contain a core set of virulence genes whose coordinated expression results in the invasion of host colonic epithelial cells and the dysenteric syndrome. A number of virulence determinants are carried by the 230 kb invasion plasmid found in all virulent strains of Shigellae. Many of these invasion plasmid genes encode immunogens that are recognized by convalescent serum, including proteins that mediate the invasion (IpaB, IpaC, IpaD) and cell spreading (VirG or IcsA and IcsB) phenotypes. In this report, we describe the molecular characterization of a novel invasion plasmid antigen from Shigella flexneri, designated IpaJ. The ipaJ gene encodes a 780 bp open reading frame (ORF), separated from the ipaR (virB) stop codon by 944 bp. The predicted amino acid sequence for IpaJ revealed a consensus signal peptide for protein export. TnphoA mutagenesis of the ipaJ ORF confirmed the presence of export signal sequences in IpaJ. Unlike ipaBCDA genes, transcription analysis of ipaJ indicated that the gene is not expressed in a temperature-dependent fashion. The IpaJ protein was expressed and purified as a His6-tagged fusion protein that reacted with convalescent sera in Western blot analyses, confirming its identification as a Shigella immunogen. Construction and phenotypic characterization of ipaJ mutants in two serotypes of S. flexneri showed that the mutants were not compromised in their ability to invade cultured epithelial cells or to form plaques on BHK cell monolayers. In addition, the ipaJ mutants were Sereny positive indicating a capacity for intercellular dissemination; however, in the limited number of guinea-pigs tested, the keratoconjunctivitis reaction appeared attenuated.
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Affiliation(s)
- J M Buysse
- Molecular Biology Research, The Upjohn Company, Kalamazoo, MI, USA
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Oaks EV, Picking WD, Picking WL. Antibody response of monkeys to invasion plasmid antigen D after infection with Shigella spp. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1996; 3:242-5. [PMID: 8991646 PMCID: PMC170291 DOI: 10.1128/cdli.3.2.242-245.1996] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The antigen preparation most often used for determining the levels of antibodies to virulence-associated proteins of Shigella spp. consists of a mixture of proteins (including IpaB, IpaC, IpaD, and VirG*) extracted from virulent shigellae with water (water extract). To overcome the lack of specificity for individual antigens in the water-extract enzyme-linked immunosorbent assay (ELISA), the ipaD gene from S. flexneri has been cloned, expressed to a high level, and purified for use in a new ELISA for the determination of the levels of antibody against IpaD in monkeys and humans challenged with shigellae. The IpaD ELISA for serum immunoglobulins G and A correlated well with the water-extract ELISA in that monkeys infected with S. flexneri or S. sonnei responded with high serum antibody titers in both assays. The IpaD assay required less antigen per well, had much lower background levels, and did not require correction with antigens from an avirulent organism. In conjunction with the water-extract ELISA, it was possible to identify infected animals that did not respond to IpaD but did produce antibodies that reacted in the water-extract ELISA. This indicates that even though IpaB, IpaC, and IpaD are essential for the invasiveness phenotype, the infected host does not always produce antibodies against all components of the invasiveness apparatus.
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Affiliation(s)
- E V Oaks
- Department of Enteric Infections, Walter Reed Army Institute of Research, Washington, D.C. 20307, USA
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Turbyfill KR, Joseph SW, Oaks EV. Recognition of three epitopic regions on invasion plasmid antigen C by immune sera of rhesus monkeys infected with Shigella flexneri 2a. Infect Immun 1995; 63:3927-35. [PMID: 7558301 PMCID: PMC173552 DOI: 10.1128/iai.63.10.3927-3935.1995] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The invasive ability of Shigella spp. is correlated with the expression of several plasmid-encoded proteins, including invasion plasmid antigen C (IpaC). By characterizing the antigenic structure of IpaC with monoclonal antibodies and convalescent-phase sera, it may be possible to determine the physical location of specific epitopes as well as the involvement of epitopes in a protective immune response or the host's susceptibility to disease. By using overlapping octameric synthetic peptides, which together represent the entire IpaC protein, the precise linear sequence of four surface-exposed epitopes was defined for four IpaC monoclonal antibodies. Furthermore, 17 unique peptide epitopes of IpaC were mapped by using 9-day-postinfection serum samples from 13 rhesus monkeys challenged with Shigella flexneri 2a. Each individual recognized a somewhat different array of IpaC peptide epitopes after infection with shigellae. However, the epitopes were clustered within three regions of the protein: region I (between amino acid residues 1 and 61), region II (between amino acid residues 177 and 258), and region III (between amino acid residues 298 and 307). Region II was recognized by 92% of S. flexneri-infected individuals and was considered to be a highly immunogenic region. Animals asymptomatic for shigellosis after challenge with S. flexneri recognized peptide epitopes within all three epitopic regions of IpaC, whereas symptomatic animals recognized peptides in only one or two of the epitopic regions. Antibody from monkeys challenged with S. sonnei recognized IpaC peptide epitopes which fell within and outside the three S. flexneri epitopic regions. While numerous potential epitopes exist on the IpaC protein, the identification of three regions in which epitopes are clustered suggests that these regions are significant with respect to the immune response and to subsequent pathogenesis postinfection.
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Affiliation(s)
- K R Turbyfill
- Department of Enteric Infections, Walter Reed Army Institute of Research, Washington, D.C. 20307, USA
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Li A, Zhao CR, Ekwall E, Lindberg AA. Serum IgG antibody responses to Shigella invasion plasmid-coded antigens detected by immunoblot. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 1994; 26:435-45. [PMID: 7984976 DOI: 10.3109/00365549409008617] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Serum IgG antibody responses to Shigella invasion plasmid-coded antigens (Ipa) from 58 Shigella flexneri, S. sonnei, and S. dysenteriae infected Swedish patients were investigated by immunoblot technique. Intense responses to most components of Ipa (Ipas A, B, C, D, and VirG-virulence determinant on SalI fragment G of the plasmid) were evident in sera from S. flexneri infected patients. The strongest response was to Ipa B and the weakest, to Ipa D. In contrast, there were weaker responses to Ipas A, B, C, and VirG but none at all to Ipa D in sera from S. sonnei infected patients. After absorption of the Ipa-positive sera by Ipa expressing strains of S. flexneri and S. sonnei, most IgG antibodies to components of Ipa were removed in sera absorbed by S. flexneri, but IgG antibodies to Ipas--especially to Ipa D--were only slightly reduced in sera absorbed by S. sonnei, suggesting that Ipa D in S. sonnei may not be exposed on the S. sonnei cell surface.
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Affiliation(s)
- A Li
- Department of Clinical Bacteriology, Karolinska Institute, Huddinge Hospital, Sweden
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