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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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MacLennan CA, Grow S, Ma LF, Steele AD. The Shigella Vaccines Pipeline. Vaccines (Basel) 2022; 10:vaccines10091376. [PMID: 36146457 PMCID: PMC9504713 DOI: 10.3390/vaccines10091376] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/06/2022] [Accepted: 08/10/2022] [Indexed: 11/22/2022] Open
Abstract
Shigella is the leading cause of global diarrheal deaths that currently lacks a licensed vaccine. Shigellosis drives antimicrobial resistance and leads to economic impact through linear growth faltering. Today, there is a robust pipeline of vaccines in clinical development which are broadly divided into parenteral glycoconjugate vaccines, consisting of O-antigen conjugated to carrier proteins, and oral live attenuated vaccines, which incorporate targeted genetic mutations seeking to optimize the balance between reactogenicity, immunogenicity and ultimately protection. Proof of efficacy has previously been shown with both approaches but for various reasons no vaccine has been licensed to date. In this report, we outline the requirements for a Shigella vaccine and describe the current pipeline in the context of the many candidates that have previously failed or been abandoned. The report refers to papers from individual vaccine developers in this special supplement of Vaccines which is focused on Shigella vaccines. Once readouts of safety and immunogenicity from current trials of lead candidate vaccines among the target population of young children in low- and middle-income countries are available, the likely time to licensure of a first Shigella vaccine will become clearer.
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Sarker P, Mily A, Ara A, Haque F, Maier N, Wierzba TF, Walker RI, Venkatesan MM, Raqib R. Functional antibodies and innate immune responses to WRSS1, a live oral Shigella sonnei vaccine candidate in Bangladeshi adults and children. J Infect Dis 2021; 224:S829-S839. [PMID: 34374425 PMCID: PMC8687094 DOI: 10.1093/infdis/jiab395] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background We demonstrated in a randomized placebo-controlled trial that WRSS1, a live oral Shigella sonnei vaccine candidate, is safe in Bangladeshi adults and children, and elicits antigen-specific antibodies. Here, we describe functional antibody and innate immune responses to WRSS1. Methods Adults (18–39 years) and children (5–9 years) received 3 doses of 3 × 105 or 3 × 106 colony forming units (CFU) of WRSS1 or placebo, 4 weeks apart; children additionally received 3 × 104 CFU. Blood and stool were collected at baseline and 7 days after each dose. Functional antibodies were measured using serum bactericidal antibody (SBA) assay. Cytokine/chemokine concentrations were measured in lymphocyte cultures. Host defense peptides LL-37, HBD-1, and HD-5 were analyzed in plasma and stool. Results Children showed increased SBA titers over baseline after the third dose of 3 × 106 CFU (P = .048). Significant increases of Th-17 and proinflammatory cytokines (TNF-α, G-CSF, MIP-1β), and reduction of anti-inflammatory and Th2 cytokines (IL-10, IL-13, GM-CSF) were observed in children. Plasma HBD-1 and LL-37 decreased in children after vaccination but were increased/unchanged in adults. Conclusions Functional antibodies and Th1/Th17 cytokine responses in children may serve as important indicators of immunogenicity and protective potential of WRSS1. Clinical Trials Registration: NCT01813071.
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Affiliation(s)
- Protim Sarker
- Infectious Diseases Division, icddr,b, Dhaka, Bangladesh
| | | | - Anjuman Ara
- Infectious Diseases Division, icddr,b, Dhaka, Bangladesh
| | - Farjana Haque
- Infectious Diseases Division, icddr,b, Dhaka, Bangladesh
| | - Nicole Maier
- Center for Vaccine Innovation and Access, PATH, Washington DC, USA
| | - Thomas F Wierzba
- Center for Vaccine Innovation and Access, PATH, Washington DC, USA
| | - Richard I Walker
- Center for Vaccine Innovation and Access, PATH, Washington DC, USA
| | - Malabi M Venkatesan
- Bacterial Diseases Branch, Walter Reed Army Institute of Research (WRAIR), Maryland, USA
| | - Rubhana Raqib
- Infectious Diseases Division, icddr,b, Dhaka, Bangladesh
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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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Harutyunyan S, Neuhauser I, Mayer A, Aichinger M, Szijártó V, Nagy G, Nagy E, Girardi P, Malinoski FJ, Henics T. Characterization of ShigETEC, a Novel Live Attenuated Combined Vaccine against Shigellae and ETEC. Vaccines (Basel) 2020; 8:vaccines8040689. [PMID: 33207794 PMCID: PMC7712393 DOI: 10.3390/vaccines8040689] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/16/2022] Open
Abstract
Background: Shigella spp. and enterotoxigenic Escherichia coli (ETEC) remain the two leading bacterial causes of diarrheal diseases worldwide. Attempts to develop preventive vaccines against Shigella and ETEC have not yet been successful. The major challenge for a broad Shigella vaccine is the serotype-specific immune response to the otherwise protective LPS O-antigen. ETEC vaccines mainly rely on the heat-labile enterotoxin (LT), while heat-stable toxin (ST) has also been shown to be an important virulence factor. Methods: We constructed a combined Shigella and ETEC vaccine (ShigETEC) based on a live attenuated Shigella strain rendered rough and non-invasive with heterologous expression of two ETEC antigens, LTB and a detoxified version of ST (STN12S). This new vaccine strain was characterized and tested for immunogenicity in relevant animal models. Results: Immunization with ShigETEC resulted in serotype independent protection in the mouse lung shigellosis model and induced high titer IgG and IgA antibodies against bacterial lysates, and anti-ETEC toxin antibodies with neutralizing capacity. Conclusions: ShigETEC is a promising oral vaccine candidate against Shigella and ETEC infections and currently in Phase 1 testing.
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Affiliation(s)
- Shushan Harutyunyan
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Irene Neuhauser
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Alexandra Mayer
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Michael Aichinger
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Valéria Szijártó
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Gábor Nagy
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
- CEBINA GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria
| | - Eszter Nagy
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
- CEBINA GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria
| | - Petra Girardi
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Frank J. Malinoski
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
| | - Tamás Henics
- Eveliqure Biotechnologies GmbH, Karl-Farkas-Gasse 22, 1030 Vienna, Austria; (S.H.); (I.N.); (A.M.); (M.A.); (V.S.); (G.N.); (E.N.); (P.G.); (F.J.M.)
- Correspondence: ; Tel.: +43-1-909-2208-3313
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Gilavand F, Marzban A, Ebrahimipour G, Soleimani N, Goudarzi M. Designation of chitosan nano-vaccine based on MxiH antigen of Shigella flexneri with increased immunization capacity. Carbohydr Polym 2019; 232:115813. [PMID: 31952611 DOI: 10.1016/j.carbpol.2019.115813] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/18/2019] [Accepted: 12/29/2019] [Indexed: 12/31/2022]
Abstract
Shigella flexneri is a gram-negative pathogen that causes shigellosis in humans and primates. MxiH antigen is known as one of the invasive factors in most Gram-negative bacteria consisting of a needle-like structure in the main backbone of the type 3 secretory system. Recombinant MxiH antigen was produced by E. coli BL21 and purified antigen was loaded into chitosan nanoparticles (CS-MxiH). After 20thand 55th of intranasal vaccinations, the titers of IgG, IgA, IL-4, and IFN-γ were evaluated. The results indicated the successful synthesis of CS nanoparticles followed by the effective loading of MxiH antigen. The results of animal experiments showed that the intranasal administration of CS-MxiH increased IgG and IgA compared to control groups. Increased levels of IL-4 and IFN-γ in groups immunized with CS-MxiH are probably due to the activation of plasmacytoid and myeloid cells presenting antigen in nasal epithelial mucosa and stimulating B cells.
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Affiliation(s)
- Farhad Gilavand
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | - Abdolrazagh Marzban
- Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran.
| | - Gholamhossein Ebrahimipour
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | - Neda Soleimani
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | - Mehdi Goudarzi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Jarząb A, Witkowska D, Ziomek E, Setner B, Czajkowska A, Dorot M, Szewczuk Z, Gamian A. Cyclic OmpC peptidic epitope conjugated to tetanus toxoid as a potential vaccine candidate against shigellosis. Vaccine 2018; 36:4641-4649. [PMID: 29960802 DOI: 10.1016/j.vaccine.2018.06.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/22/2018] [Accepted: 06/17/2018] [Indexed: 11/29/2022]
Abstract
In earlier works we have described that mice immunized with outer membrane protein OmpC survive the challenge with live Shigella flexnerii 3a. We have also identified conformational epitope of this protein, that was recognized by mice antibodies. The aim of current work was to investigate whether synthetic OmpC epitope homologs can elicit immunological response sufficient in protecting mice against shigellosis. Several linear peptides containing RYDERY motif were synthesized and conjugated to poly-lysine. These conjugates appeared to be poor immunogens and to boost the immunological response an addition of the adjuvant (MPL) was required. Unfortunately, the MPL alone caused a very high immunological reaction that was masking response to peptidic epitope. Under those circumstances we used tetanus toxoid (TT) as the carrier protein for the peptides and the agent stimulating immunological response. Series of cyclic peptides, homologs of the OmpC main epitope were synthesized and conjugated to TT. The loop size in cyclic peptides varied by number of glycine residues, i.e., 1-3 residues added to the GLNRYDERYIGK motif. The linear GLNRYDERYIGC-TT was also prepared as the control. The latter conjugate gave the highest immunological response, followed by the cyclic-GGLNRYDERYIGC-TT and cyclic-GLNRYDERYIGC-TT. The third peptide, cyclic-GGGLNRYDERYIGC-TT, gave a very low response, although it was the most resistant to proteolysis. However, antibodies obtained against cyclic-GGLNRYDERYIGC-TT were more potent to recognize both OmpC and Shigella flexnerii 3a cells than the antibodies against linear GLNRYDERYIGC-TT. Furthermore, the monoclonal antibodies raised against linear GLNRYDERYIGC-TT showed 20-fold lower dissociation constant (KD) than the naturally occurring polyclonal antibodies from umbilical cord sera. Monoclonal antibodies also gave a weaker signal in electron microscope than mice and human polyclonal antibodies. In overall, our results point to cyclic peptides as better candidates for a vaccine development, since they are eliciting production of the higher affinity antibodies against Shigella cells and OmpC.
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Affiliation(s)
- Anna Jarząb
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland; Wroclaw Research Center EIT+, Wroclaw, Poland
| | - Danuta Witkowska
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland; Wroclaw Research Center EIT+, Wroclaw, Poland.
| | | | - Bartosz Setner
- Faculty of Chemistry, University of Wroclaw, Wroclaw, Poland
| | - Aleksandra Czajkowska
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Małgorzata Dorot
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | | | - Andrzej Gamian
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland; Wroclaw Research Center EIT+, Wroclaw, Poland
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Toapanta FR, Bernal PJ, Kotloff KL, Levine MM, Sztein MB. T cell mediated immunity induced by the live-attenuated Shigella flexneri 2a vaccine candidate CVD 1208S in humans. J Transl Med 2018. [PMID: 29534721 PMCID: PMC5851169 DOI: 10.1186/s12967-018-1439-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Shigellosis persists as a public health problem worldwide causing ~ 165,000 deaths every year, of which ~ 55,000 are in children less than 5 years of age. No vaccine against shigellosis is currently licensed. The live-attenuated Shigella flexneri 2a vaccine candidate CVD 1208S (S. flexneri 2a; ΔguaBA, Δset, Δsen) demonstrated to be safe and immunogenic in phase 1 and 2 clinical trials. Earlier reports focused on humoral immunity. However, Shigella is an intracellular pathogen and therefore, T cell mediated immunity (T-CMI) is also expected to play an important role. T-CMI responses after CVD 1208S immunization are the focus of the current study. Methods Consenting volunteers were immunized orally (3 doses, 108 CFU/dose, 28 days apart) with CVD 1208S. T-CMI to IpaB was assessed using autologous EBV-transformed B-Lymphocytic cell lines as stimulator cells. T-CMI was assessed by the production of 4 cytokines (IFN-γ, IL-2, IL-17A and TNF-α) and/or expression of the degranulation marker CD107a in 14 volunteers (11 vaccine and 3 placebo recipients). Results Following the first immunization, T-CMI was detected in CD8 and CD4 T cells obtained from CVD 1208S recipients. Among CD8 T cells, the T effector memory (TEM) and central memory (TCM) subsets were the main cytokine/CD107a producers/expressors. Multifunctional (MF) cells were also detected in CD8 TEM cells. Cells with 2 and 3 functions were the most abundant. Interestingly, TNF-α appeared to be dominant in CD8 TEM MF cells. In CD4 T cells, TEM responses predominated. Following subsequent immunizations, no booster effect was detected. However, production of cytokines/expression of CD107a was detected in individuals who had previously not responded. After three doses, production of at least one cytokine/CD107a was detected in 8 vaccinees (73%) in CD8 TEM cells and in 10 vaccinees (90%) in CD4 TEM cells. Conclusions CVD 1208S induces diverse T-CMI responses, which likely complement the humoral responses in protection from disease. Trial registration This study was approved by the Institutional Review Board and registered on ClinicalTrials.gov (identifier NCT01531530) Electronic supplementary material The online version of this article (10.1186/s12967-018-1439-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Franklin R Toapanta
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Paula J Bernal
- Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Karen L Kotloff
- Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Myron M Levine
- Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Marcelo B Sztein
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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Davis CL, Wahid R, Toapanta FR, Simon JK, Sztein MB. A clinically parameterized mathematical model of Shigella immunity to inform vaccine design. PLoS One 2018; 13:e0189571. [PMID: 29304144 PMCID: PMC5755796 DOI: 10.1371/journal.pone.0189571] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/16/2017] [Indexed: 11/28/2022] Open
Abstract
We refine and clinically parameterize a mathematical model of the humoral immune response against Shigella, a diarrheal bacteria that infects 80-165 million people and kills an estimated 600,000 people worldwide each year. Using Latin hypercube sampling and Monte Carlo simulations for parameter estimation, we fit our model to human immune data from two Shigella EcSf2a-2 vaccine trials and a rechallenge study in which antibody and B-cell responses against Shigella′s lipopolysaccharide (LPS) and O-membrane proteins (OMP) were recorded. The clinically grounded model is used to mathematically investigate which key immune mechanisms and bacterial targets confer immunity against Shigella and to predict which humoral immune components should be elicited to create a protective vaccine against Shigella. The model offers insight into why the EcSf2a-2 vaccine had low efficacy and demonstrates that at a group level a humoral immune response induced by EcSf2a-2 vaccine or wild-type challenge against Shigella′s LPS or OMP does not appear sufficient for protection. That is, the model predicts an uncontrolled infection of gut epithelial cells that is present across all best-fit model parameterizations when fit to EcSf2a-2 vaccine or wild-type challenge data. Using sensitivity analysis, we explore which model parameter values must be altered to prevent the destructive epithelial invasion by Shigella bacteria and identify four key parameter groups as potential vaccine targets or immune correlates: 1) the rate that Shigella migrates into the lamina propria or epithelium, 2) the rate that memory B cells (BM) differentiate into antibody-secreting cells (ASC), 3) the rate at which antibodies are produced by activated ASC, and 4) the Shigella-specific BM carrying capacity. This paper underscores the need for a multifaceted approach in ongoing efforts to design an effective Shigella vaccine.
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Affiliation(s)
- Courtney L. Davis
- Natural Science Division, Pepperdine University, Malibu, CA, United States of America
- * E-mail:
| | - Rezwanul Wahid
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Franklin R. Toapanta
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Jakub K. Simon
- Merck & Co. Inc. Kenilworth, NJ, United States of America
| | - Marcelo B. Sztein
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, United States of America
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Abstract
Shigellosis is one of the major causes of diarrhoea in India. The accurate estimates of morbidity and mortality due to shigellosis are lacking, though it is endemic in the country and has been reported to cause many outbreaks. The limited information available indicates Shigella to be an important food-borne pathogen in India. S. flexneri is the most common species, S. sonnei and non-agglutinable shigellae seem to be steadily surfacing, while S. dysenteriae has temporarily disappeared from the northern and eastern regions. Antibiotic-resistant strains of different Shigella species and serotypes have emerged all over the world. Especially important is the global emergence of multidrug resistant shigellae, notably the increasing resistance to third generation cephalosporins and fluoroquinolones, and also azithromycin. This calls for a continuous and strong surveillance of antibiotic resistance across the country for periodic updation of the local antibiograms. The prevention of shigellosis is desirable as it will substantially reduce the morbidity associated with diarrhoea in the country. Public health measures like provision of safe water and adequate sanitation are of immense importance to reduce the burden of shigellosis, however, the provision of resources to develop such an infrastructure in India is a complex issue and will take time to resolve. Thus, the scientific thrust should be focused towards development of a safe and affordable multivalent vaccine. This review is focused upon the epidemiology, disease burden and the therapeutic challenges of shigellosis in Indian perspective.
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Affiliation(s)
- Neelam Taneja
- Department of Medical Microbiology, Postgraduate Institute of Medical Education & Research, Chandigarh, India
| | - Abhishek Mewara
- Department of Medical Parasitology, Postgraduate Institute of Medical Education & Research, Chandigarh, India
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Abstract
Shigellosis remains a serious issue throughout the developing countries, particularly in children under the age of 5. Numerous strategies have been tested to develop vaccines targeting shigellosis; unfortunately despite several years of extensive research, no safe, effective, and inexpensive vaccine against shigellosis is available so far. Here, we illustrate in detail an approach to identify and establish immunogenic outer membrane proteins from Shigella flexneri 2a as subunit vaccine candidates.
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Nag D, Koley H, Sinha R, Mukherjee P, Sarkar C, Withey JH, Gachhui R. Immunization of Mice with a Live Transconjugant Shigella Hybrid Strain Induced Th1 and Th17 Cell-Mediated Immune Responses and Confirmed Passive Protection Against Heterologous Shigellae. Scand J Immunol 2016; 83:92-101. [PMID: 26478541 DOI: 10.1111/sji.12394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/06/2015] [Indexed: 02/03/2023]
Abstract
An avirulent, live transconjugant Shigella hybrid (LTSHΔstx) strain was constructed in our earlier study by introducing a plasmid vector, pPR1347, into a Shiga toxin gene deleted Shigella dysenteriae 1. Three successive oral administrations of LTSHΔstx to female adult mice produced comprehensive passive heterologous protection in their offspring against challenge with wild-type shigellae. Production of NO and different cytokines such asIL-12p70, IL-1β and IL-23 in peritoneal mice macrophages indicated that LTSHΔstx induced innate and adaptive immunity in mice. Furthermore, production of IFN-γ, IL-10 and IL-17 in LTSH-primed splenic CD4+ T cell suggested that LTSHΔstx may induce Th1 and Th17 cell-mediated immune responses. Exponential increase of the serum IgG and IgA titre against whole shigellae was observed in immunized adult mice during and after the immunization with the highest peak on day 35. Antigen-specific sIgA was also determined from intestinal lavage of immunized mice. The stomach extracts of neonates from immunized mice, mainly containing mother's milk, contained significant levels of anti-LTSHΔstx immunoglobulin. These studies suggest that the LTSHΔstx could be a new live oral vaccine candidate against shigellosis in the near future.
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Affiliation(s)
- D Nag
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - H Koley
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - R Sinha
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - P Mukherjee
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - C Sarkar
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - J H Withey
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - R Gachhui
- Department of Life Science and Technology, Jadavpur University, Kolkata, India
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13
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Santiago AE, Mann BJ, Qin A, Cunningham AL, Cole LE, Grassel C, Vogel SN, Levine MM, Barry EM. Characterization of Francisella tularensis Schu S4 defined mutants as live-attenuated vaccine candidates. Pathog Dis 2015; 73:ftv036. [PMID: 25986219 PMCID: PMC4462183 DOI: 10.1093/femspd/ftv036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2015] [Indexed: 01/11/2023] Open
Abstract
Francisella tularensis (Ft), the etiological agent of tularemia and a Tier 1 select agent, has been previously weaponized and remains a high priority for vaccine development. Ft tularensis (type A) and Ft holarctica (type B) cause most human disease. We selected six attenuating genes from the live vaccine strain (LVS; type B), F. novicida and other intracellular bacteria: FTT0507, FTT0584, FTT0742, FTT1019c (guaA), FTT1043 (mip) and FTT1317c (guaB) and created unmarked deletion mutants of each in the highly human virulent Ft strain Schu S4 (Type A) background. FTT0507, FTT0584, FTT0742 and FTT1043 Schu S4 mutants were not attenuated for virulence in vitro or in vivo. In contrast, Schu S4 gua mutants were unable to replicate in murine macrophages and were attenuated in vivo, with an i.n. LD50 > 105 CFU in C57BL/6 mice. However, the gua mutants failed to protect mice against lethal challenge with WT Schu S4, despite demonstrating partial protection in rabbits in a previous study. These results contrast with the highly protective capacity of LVS gua mutants against a lethal LVS challenge in mice, and underscore differences between these strains and the animal models in which they are evaluated, and therefore have important implications for vaccine development. Mutations in guanine biosynthesis genes, but not in four other hypothetical virulence factors in highly virulent Francisella tularensis strain Schu S4 resulted in attenuation in macrophage replication and mouse virulence.
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Affiliation(s)
- Araceli E Santiago
- Departments of Pediatrics, University of Virginia Children's Hospital, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Barbara J Mann
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Aiping Qin
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Aimee L Cunningham
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Leah E Cole
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Christen Grassel
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Stefanie N Vogel
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Eileen M Barry
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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15
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Böhles N, Böhles N, Busch K, Busch K, Hensel M, Hensel M. Vaccines against human diarrheal pathogens: current status and perspectives. Hum Vaccin Immunother 2014; 10:1522-35. [PMID: 24861668 PMCID: PMC5396248 DOI: 10.4161/hv.29241] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 12/16/2022] Open
Abstract
Worldwide, nearly 1.7 billion people per year contract diarrheal infectious diseases (DID) and almost 760 000 of infections are fatal. DID are a major problem in developing countries where poor sanitation prevails and food and water may become contaminated by fecal shedding. Diarrhea is caused by pathogens such as bacteria, protozoans and viruses. Important diarrheal pathogens are Vibrio cholerae, Shigella spp. and rotavirus, which can be prevented with vaccines for several years. The focus of this review is on currently available vaccines against these three pathogens, and on development of new vaccines. Currently, various types of vaccines based on traditional (killed, live attenuated, toxoid or conjugate vaccines) and reverse vaccinology (DNA/mRNA, vector, recombinant subunit, plant vaccines) are in development or already available. Development of new vaccines demands high levels of knowledge, experience, budget, and time, yet promising new vaccines often fail in preclinical and clinical studies. Efficacy of vaccination also depends on the route of delivery, and mucosal immunization in particular is of special interest for preventing DID. Furthermore, adjuvants, delivery systems and other vaccine components are essential for an adequate immune response. These aspects will be discussed in relation to the improvement of existing and development of new vaccines against DID.
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Affiliation(s)
| | | | | | | | - Michael Hensel
- Abt. Mikrobiologie; Universität Osnabrück; Osnabrück, Germany
| | - Michael Hensel
- Abt. Mikrobiologie; Universität Osnabrück; Osnabrück, Germany
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16
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Abstract
Several live-attenuated Shigella vaccines, with well-defined mutations in specific genes, have shown great promise in eliciting significant immune responses when given orally to volunteers. These responses have been measured by evaluating antibody-secreting cells, serum antibody levels and fecal immunoglobulin A to bacterial lipopolysaccharide and to individual bacterial invasion plasmid antigens. In this review, data collected from volunteer trials with live Shigella vaccines from three different research groups are described. The attenuating features of the bacterial strains, as well as the immune response following the use of different dosing regimens, are also described. The responses obtained with each vaccine strain are compared with data obtained from challenge trials using wild-type Shigella strains. Although the exact correlates of protection have not been found, some consensus may be derived as to what may constitute a protective immune response. Future directions in the field of live Shigella vaccines are also discussed.
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Affiliation(s)
- Malabi M Venkatesan
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, 503 Robert Forney Drive, Room 3s12, Silver Spring, MD 20910, USA.
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17
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Daudel D, Weidinger G, Spreng S. Use of attenuated bacteria as delivery vectors for DNA vaccines. Expert Rev Vaccines 2014; 6:97-110. [PMID: 17280482 DOI: 10.1586/14760584.6.1.97] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Live, attenuated bacterial vaccines (LBV) are promising candidates for the induction of a broad-based immune response directed at recombinant heterologous antigens and the corresponding pathogen. LBVs allow vaccination through the mucosal surfaces and specific targeting of professional antigen-presenting cells located at the inductive sites of the immune system. A novel approach exploits attenuated intracellular bacteria as delivery vectors for eukaryotic antigen-expression plasmids (so-called DNA vaccines). Candidate carrier bacteria include attenuated strains of Gram-positive and Gram-negative bacteria. These bacteria have been shown to deliver DNA vaccines to human cells in vitro and have also proven their in vivo efficacy in several experimental animal models of infectious diseases and different cancers. The clinical assessment of the safety, immunogenicity and efficacy of these candidate strains will be the next challenging step towards live bacterial DNA vaccines.
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Affiliation(s)
- Damini Daudel
- Berna Biotech AG, Rehhagstrasse 79, CH-3018 Berne, Switzerland.
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Xu D, Yang X, Wang D, Yu J, Wang Y. Surface display of the HPV L1 capsid protein by the autotransporter Shigella IcsA. J Microbiol 2014; 52:77-82. [DOI: 10.1007/s12275-014-3235-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/29/2013] [Accepted: 08/05/2013] [Indexed: 11/29/2022]
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Xu D, Wang D, Yang X, Cao M, Yu J, Wang Y. Fusion of HPV L1 into Shigella surface IcsA: a new approach in developing live attenuated Shigella-HPV vaccine. Antiviral Res 2013; 102:61-9. [PMID: 24333518 DOI: 10.1016/j.antiviral.2013.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 11/05/2013] [Accepted: 12/09/2013] [Indexed: 11/16/2022]
Abstract
Despite the success of L1 virus-like particles (VLPs) vaccines in prevention of high-risk human papillomavirus (HPV) infection and cervical cancer, extraordinary high cost for the complete vaccination has impeded widespread use of the vaccine in resource-poor countries, where cervical cancers impose greater challenge. Presentation of HPV L1 protein by attenuated pathogenic bacteria through natural infection provides a promising low-cost and convenient alternative. Here, we describe the construction and characterization of attenuated L1-expressing Shigella vaccine candidate, by fusion of L1 into the autotransporter of Shigella sonnei, IcsA, an essential virulence factor responsible for actin-based motility. The functional α domain of IcsA was replaced by codon-optimized L1 gene with independent open reading frames (ORFs) facilitated by suicide vector pJCB12. The L1 gene was stabilized in the genome of recombinant S. sonnei with protein expression and assembly of VLPs in the bacterial cytoplasm. Through conjunctival route vaccination in guinea pigs, L1-containing S. sonnei was able to elicit specific immune response to HPV16 L1 VLP as well as bacterial antigens. The results demonstrated the feasibility of the novel stratagem to develop prophylactic Shigella-HPV vaccines.
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Affiliation(s)
- Dan Xu
- Institute of Cancer Research, School of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an 710061, China; Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Depu Wang
- Institute of Cancer Research, School of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Xiaofeng Yang
- The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Meng Cao
- Institute of Cancer Research, School of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an 710061, China
| | - Jun Yu
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Yili Wang
- Institute of Cancer Research, School of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an 710061, China.
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20
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Analysis of the proteome of intracellular Shigella flexneri reveals pathways important for intracellular growth. Infect Immun 2013; 81:4635-48. [PMID: 24101689 DOI: 10.1128/iai.00975-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Global proteomic analysis was performed with Shigella flexneri strain 2457T in association with three distinct growth environments: S. flexneri growing in broth (in vitro), S. flexneri growing within epithelial cell cytoplasm (intracellular), and S. flexneri that were cultured with, but did not invade, Henle cells (extracellular). Compared to in vitro and extracellular bacteria, intracellular bacteria had increased levels of proteins required for invasion and cell-to-cell spread, including Ipa, Mxi, and Ics proteins. Changes in metabolic pathways in response to the intracellular environment also were evident. There was an increase in glycogen biosynthesis enzymes, altered expression of sugar transporters, and a reduced amount of the carbon storage regulator CsrA. Mixed acid fermentation enzymes were highly expressed intracellularly, while tricarboxylic acid (TCA) cycle oxidoreductive enzymes and most electron transport chain proteins, except CydAB, were markedly decreased. This suggested that fermentation and the CydAB system primarily sustain energy generation intracellularly. Elevated levels of PntAB, which is responsible for NADPH regeneration, suggested a shortage of reducing factors for ATP synthesis. These metabolic changes likely reflect changes in available carbon sources, oxygen levels, and iron availability. Intracellular bacteria showed strong evidence of iron starvation. Iron acquisition systems (Iut, Sit, FhuA, and Feo) and the iron starvation, stress-associated Fe-S cluster assembly (Suf) protein were markedly increased in abundance. Mutational analysis confirmed that the mixed-acid fermentation pathway was required for wild-type intracellular growth and spread of S. flexneri. Thus, iron stress and changes in carbon metabolism may be key factors in the S. flexneri transition from the extra- to the intracellular milieu.
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21
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Mao Y, Cui E, Bao C, Liu Z, Chen S, Zhang J, Wang H, Zhang C, Zou J, Klena JD, Zhu B, Qu F, Wang Z. Changing trends and serotype distribution of Shigella species in Beijing from 1994 to 2010. Gut Pathog 2013; 5:21. [PMID: 23919811 PMCID: PMC3750644 DOI: 10.1186/1757-4749-5-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 07/31/2013] [Indexed: 10/28/2022] Open
Abstract
Shigella species are a common cause of acute diarrheal disease in China. In this study, we characterized the changing trends and serotype distribution of Shigella species in Beijing from 1994 to 2010. A total of 5999 Shigella strains were isolated and serotyped from the 302nd Hospital in Beijing. The annual number of Shigella isolates reached a peak (n = 1192; 19.84%) in 1996 and then decreased annually, reaching the lowest point (n = 24; 0.41%) in 2010. S. flexneri 2a and S. sonnei were the most frequently isolated Shigella, with their respective isolates making up 53.3% and 27.6% of the total. Isolates of S. flexneri 4c, 4a, and x made up 3% respectively of the total isolates. Significant decreases in percentage of S. flexneri over time were observed. S. sonnei surpassed S. flexneri 2a as the predominant serotype in 2000. Most isolates were recovered from July to September; 13.6% of the isolates were recovered from children aged 0 to 5 years, and 16% were recovered from those aged 21 to 25 years. S. flexneri 2a and 5 were recovered mostly from males (33.41%, p < 0.001; and 0.46%, p < 0.001%; respectively), whereas S. flexneri 2b and 6, and S. sonnei were most often isolated from females. Continuous monitoring of Shigella showed that all 4 species and 27 serotypes were present in Beijing, China, during the study period. The emergence of S. sonnei and the overall decreasing isolation rate of Shigella in Beijing can potentially aid in the development of vaccine and control strategies for shigellosis in the city.
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Affiliation(s)
- Yuanli Mao
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Enbo Cui
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Chunmei Bao
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Zhenhong Liu
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Suming Chen
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Juling Zhang
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Huan Wang
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Chenglong Zhang
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Jing Zou
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - John D Klena
- School of Basic Medical Sciences, Peking University, Beijing 100083, PR China
| | - Baoli Zhu
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Fen Qu
- Clinical Diagnostic Center, 302nd Hospital of the People's Liberation Army, Beijing 100039, PR China
| | - Zhiyun Wang
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
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22
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Pore D, Chakrabarti MK. Outer membrane protein A (OmpA) from Shigella flexneri 2a: a promising subunit vaccine candidate. Vaccine 2013; 31:3644-50. [PMID: 23764536 DOI: 10.1016/j.vaccine.2013.05.100] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/20/2013] [Accepted: 05/24/2013] [Indexed: 02/08/2023]
Abstract
Shigellosis is the leading cause of childhood mortality and morbidity. Despite many years of extensive research a practical vaccine is not yet available against the disease. Recent studies illustrate that bacterial outer membrane proteins are budding target as vaccine antigen. Outer membrane proteins A (OmpA) are among the most immunodominant antigens in the outer membrane of gram negative bacteria and possess many characteristics desired of a vaccine candidate. We observe that OmpA of Shigella flexneri 2a is crossreactive and common antigen among Shigella spp. and the epitope is widely exposed on the cell surface as well as capable of evoking protective immunity in mice. The protective immunity involves participation of both the humoral and cellular immune responses, since OmpA boosts rapid induction of IgG and IgA in both the systemic and mucosal compartments and also activates Th1 cells. The immunopotentiating activity of OmpA is mediated by its ability to bind and stimulate macrophages and up-regulate the surface expression of MHCII, CD80 and CD40, leading to activation of CD4(+) T cells to secrete cytokines and express chemokine receptor and IL-12Rβ2, thereby orchestrating the bridge between innate and adaptive immune responses. This ability is dependent on Toll-like receptor 2 (TLR2), as demonstrated by lack of response by TLR2 knockdown macrophages to OmpA. Hence this property of OmpA to link innate and adaptive immunity via TLR2 offers a novel vista to develop vaccine against shigellosis.
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Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
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Davis CL, Wahid R, Toapanta FR, Simon JK, Sztein MB, Levy D. Applying mathematical tools to accelerate vaccine development: modeling Shigella immune dynamics. PLoS One 2013; 8:e59465. [PMID: 23589755 PMCID: PMC3614931 DOI: 10.1371/journal.pone.0059465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 02/11/2013] [Indexed: 12/02/2022] Open
Abstract
We establish a mathematical framework for studying immune interactions with Shigella, a bacteria that kills over one million people worldwide every year. The long-term goal of this novel approach is to inform Shigella vaccine design by elucidating which immune components and bacterial targets are crucial for establishing Shigella immunity. Our delay differential equation model focuses on antibody and B cell responses directed against antigens like lipopolysaccharide in Shigella’s outer membrane. We find that antibody-based vaccines targeting only surface antigens cannot elicit sufficient immunity for protection. Additional boosting prior to infection would require a four-orders-of-magnitude increase in antibodies to sufficiently prevent epithelial invasion. However, boosting anti-LPS B memory can confer protection, which suggests these cells may correlate with immunity. We see that IgA antibodies are slightly more effective per molecule than IgG, but more total IgA is required due to spatial functionality. An extension of the model reveals that targeting both LPS and epithelial entry proteins is a promising avenue to advance vaccine development. This paper underscores the importance of multifaceted immune targeting in creating an effective Shigella vaccine. It introduces mathematical models to the Shigella vaccine development effort and lays a foundation for joint theoretical/experimental/clinical approaches to Shigella vaccine design.
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Affiliation(s)
- Courtney L Davis
- Natural Science Division, Pepperdine University, Malibu, California, United States of America.
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24
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Two live attenuated Shigella flexneri 2a strains WRSf2G12 and WRSf2G15: a new combination of gene deletions for 2nd generation live attenuated vaccine candidates. Vaccine 2012; 30:5159-71. [PMID: 22658966 DOI: 10.1016/j.vaccine.2012.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 04/25/2012] [Accepted: 05/01/2012] [Indexed: 11/23/2022]
Abstract
Shigella infections are a major cause of inflammatory diarrhea and dysentery worldwide. First-generation virG-based live attenuated Shigella strains have been successfully tested in phase I and II clinical trials and are a leading approach for Shigella vaccine development. Additional gene deletions in senA, senB and msbB2 have been engineered into second-generation virG-based Shigella flexneri 2a strains producing WRSf2G12 and WRSf2G15. Both strains harbor a unique combination of gene deletions designed to increase the safety of live Shigella vaccines. WRSf2G12 and WRSf2G15 are genetically stable and highly attenuated in both cell culture and animal models of infection. Ocular immunization of guinea pigs with either strain induces robust systemic and mucosal immune responses that protect against homologous challenge with wild-type Shigella. The data support further evaluation of the second-generation strains in a phase I clinical trial.
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25
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Helicobacter pylori relies primarily on the purine salvage pathway for purine nucleotide biosynthesis. J Bacteriol 2011; 194:839-54. [PMID: 22194455 DOI: 10.1128/jb.05757-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Helicobacter pylori is a chronic colonizer of the gastric epithelium and plays a major role in the development of gastritis, peptic ulcer disease, and gastric cancer. In its coevolution with humans, the streamlining of the H. pylori genome has resulted in a significant reduction in metabolic pathways, one being purine nucleotide biosynthesis. Bioinformatic analysis has revealed that H. pylori lacks the enzymatic machinery for de novo production of IMP, the first purine nucleotide formed during GTP and ATP biosynthesis. This suggests that H. pylori must rely heavily on salvage of purines from the environment. In this study, we deleted several genes putatively involved in purine salvage and processing. The growth and survival of these mutants were analyzed in both nutrient-rich and minimal media, and the results confirmed the presence of a robust purine salvage pathway in H. pylori. Of the two phosphoribosyltransferase genes found in the H. pylori genome, only gpt appears to be essential, and an Δapt mutant strain was still capable of growth on adenine, suggesting that adenine processing via Apt is not essential. Deletion of the putative nucleoside phosphorylase gene deoD resulted in an inability of H. pylori to grow on purine nucleosides or the purine base adenine. Our results suggest a purine requirement for growth of H. pylori in standard media, indicating that H. pylori possesses the ability to utilize purines and nucleosides from the environment in the absence of a de novo purine nucleotide biosynthesis pathway.
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Barman S, Kumar R, Chowdhury G, Rani Saha D, Wajima T, Hamabata T, Ramamurthy T, Balakrish Nair G, Takeda Y, Koley H. Live non-invasive Shigella dysenteriae 1 strain induces homologous protective immunity in a guinea pig colitis model. Microbiol Immunol 2011; 55:683-93. [DOI: 10.1111/j.1348-0421.2011.00371.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Pore D, Mahata N, Pal A, Chakrabarti MK. Outer membrane protein A (OmpA) of Shigella flexneri 2a, induces protective immune response in a mouse model. PLoS One 2011; 6:e22663. [PMID: 21818362 PMCID: PMC3144247 DOI: 10.1371/journal.pone.0022663] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 06/28/2011] [Indexed: 02/03/2023] Open
Abstract
Background In our earlier studies 34 kDa outer membrane protein (OMP) of Shigella flexneri 2a has been identified as an efficient immunostimulant. Key Results In the present study MALDI-TOF MS analysis of the purified 34 kDa OMP of Shigella flexneri 2a shows considerable sequence homology (Identity 65%) with the OmpA of S. flexneri 2a. By using the specific primers, the gene of interest has been amplified from S. flexneri 2a (N.Y-962/92) genomic DNA, cloned in pET100/D-TOPO® vector and expressed using induction with isopropyl thiogalactoside (IPTG) for the first time. Immunogenicity and protective efficacy of the recombinant OmpA has been evaluated in an intranasally immunized murine pulmonary model. The recombinant protein induces significantly enhanced protein specific IgG and IgA Abs in both mucosal and systemic compartments and IgA secreting cells in the systemic compartment (spleen). The mice immunized with OmpA have been protected completely from systemic challenge with a lethal dose of virulent S. flexneri 2a. Immunization with the protein causes mild polymorphonuclear neutrophil infiltration in the lung, without inducing the release of large amounts of proinflammatory cytokines. Conclusion These results suggest that the OmpA of S. flexneri 2a can be an efficacious mucosal immunogen inducing protective immune responses. Our findings also demonstrate that antibodies and Th1 immune response may be associated with the marked protective efficacy of immunized mice after intranasal shigellae infection.
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Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Nibedita Mahata
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Amit Pal
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Manoj K. Chakrabarti
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
- * E-mail:
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28
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Farfán MJ, Toro CS, Barry EM, Nataro JP. Shigella enterotoxin-2 is a type III effector that participates in Shigella-induced interleukin 8 secretion by epithelial cells. ACTA ACUST UNITED AC 2011; 61:332-9. [PMID: 21219446 DOI: 10.1111/j.1574-695x.2011.00778.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We have previously described a protein termed Shigella enterotoxin 2 (ShET-2), which induces rises in short-circuit current in rabbit ileum mounted in the Ussing chamber. Published reports have postulated that ShET-2 may be secreted by the Shigella type III secretion system (T3SS). In this study, we show that ShET-2 secretion into the extracellular space requires the T3SS in Shigella flexneri 2a strain 2457T and a ShET-2-TEM fusion was translocated into epithelial cells in a T3SS-dependent manner. The ShET-2 gene, sen, is encoded downstream of the ospC1 gene of S. flexneri, and we show that sen is cotranscribed with this T3SS-secreted product. Considering that T3SS effectors have diverse roles in Shigella infection and that vaccine constructs lacking ShET-2 are attenuated in volunteers, we asked whether ShET-2 has a function other than its enterotoxic activity. We constructed a ShET-2 mutant in 2457T and tested its effect on epithelial cell invasion, plaque formation, guinea pig keratoconjunctivitis and interleukin 8 (IL-8) secretion from infected monolayers. Although other phenotypes were not different compared with the wild-type parent, we found that HEp-2 and T84 cells infected with the ShET-2 mutant exhibited significantly reduced IL-8 secretion into the basolateral compartment, suggesting that ShET-2 might participate in the Shigella-induced inflammation of epithelial cells.
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Affiliation(s)
- Mauricio J Farfán
- Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Luis Calvo Mackennna, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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El-Kamary SS, Pasetti MF, Mendelman PM, Frey SE, Bernstein DI, Treanor JJ, Ferreira J, Chen WH, Sublett R, Richardson C, Bargatze RF, Sztein MB, Tacket CO. Adjuvanted intranasal Norwalk virus-like particle vaccine elicits antibodies and antibody-secreting cells that express homing receptors for mucosal and peripheral lymphoid tissues. J Infect Dis 2010; 202:1649-58. [PMID: 20979455 DOI: 10.1086/657087] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Noroviruses cause significant morbidity and mortality from acute gastroenteritis in all age groups worldwide. METHODS We conducted 2 phase 1 double-blind, controlled studies of a virus-like particle (VLP) vaccine derived from norovirus GI.1 genotype adjuvanted with monophosphoryl lipid A (MPL) and the mucoadherent chitosan. Healthy subjects 18-49 years of age were randomized to 2 doses of intranasal Norwalk VLP vaccine or controls 21 days apart. Study 1 evaluated 5-, 15-, and 50-μg dosages of Norwalk antigen, and study 2 evaluated 50- and 100-μg dosages. Volunteers recorded symptoms for 7 days after dosing, and safety was followed up for 180 days. Blood samples were collected for serological profile, antibody secreting cells (ASCs), and analysis of ASC homing receptors. RESULTS The most common symptoms were nasal stuffiness, discharge, and sneezing. No vaccine-related serious adverse events occurred. Norwalk VLP-specific immunoglobulin G and immunoglobulin A antibodies increased 4.8- and 9.1-fold, respectively, for the 100-μg dosage level. All subjects tested who received the 50- or 100-μg vaccine dose developed immunoglobulin A ASCs. These cells expressed molecules associated with homing to mucosal and peripheral lymphoid tissues. CONCLUSIONS The intranasal monovalent adjuvanted Norwalk VLP vaccine was well tolerated and highly immunogenic and is a candidate for additional study.
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Affiliation(s)
- Samer S El-Kamary
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Vinh H, Nhu NTK, Nga TVT, Duy PT, Campbell JI, Hoang NVM, Boni MF, My PVT, Parry C, Nga TTT, Van Minh P, Thuy CT, Diep TS, Phuong LT, Chinh MT, Loan HT, Tham NTH, Lanh MN, Mong BL, Anh VTC, Bay PVB, Chau NVV, Farrar J, Baker S. A changing picture of shigellosis in southern Vietnam: shifting species dominance, antimicrobial susceptibility and clinical presentation. BMC Infect Dis 2009; 9:204. [PMID: 20003464 PMCID: PMC2803792 DOI: 10.1186/1471-2334-9-204] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 12/15/2009] [Indexed: 11/18/2022] Open
Abstract
Background Shigellosis remains considerable public health problem in some developing countries. The nature of Shigellae suggests that they are highly adaptable when placed under selective pressure in a human population. This is demonstrated by variation and fluctuations in serotypes and antimicrobial resistance profile of organisms circulating in differing setting in endemic locations. Antimicrobial resistance in the genus Shigella is a constant threat, with reports of organisms in Asia being resistant to multiple antimicrobials and new generation therapies. Methods Here we compare microbiological, clinical and epidemiological data from patients with shigellosis over three different periods in southern Vietnam spanning14 years. Results Our data demonstrates a shift in dominant infecting species (S. flexneri to S. sonnei) and resistance profile of the organisms circulating in southern Vietnam. We find that there was no significant variation in the syndromes associated with either S. sonnei or S. flexneri, yet the clinical features of the disease are more severe in later observations. Conclusions Our findings show a change in clinical presentation of shigellosis in this setting, as the disease may be now more pronounced, this is concurrent with a change in antimicrobial resistance profile. These data highlight the socio-economic development of southern Vietnam and should guide future vaccine development and deployment strategies. Trial Registration Current Controlled Trials ISRCTN55945881
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Affiliation(s)
- Ha Vinh
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
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Abstract
PURPOSE OF REVIEW Shigellosis, a major form of bacillary dysentery, is caused by infection with Shigella organisms. In poor countries, Shigella-caused dysentery is endemic and causes an estimated 163 million illness episodes annually and more than one million deaths. Although several strategies have been used to develop vaccines targeting shigellosis, none has been licensed for use outside China. Owing to the wide range of Shigella serotypes and subtypes, there is a need for a multivalent vaccine representing prevalent species and serotypes. RECENT FINDINGS Vaccine development has been limited by the lack of a suitable animal model for vaccine testing. This review discusses the most advanced strategies for Shigella vaccine development including live attenuated, conjugate, broad spectrum, and proteosome-based vaccines and describes current animal models under study. SUMMARY The greatest barrier to the use of vaccine against shigellosis in developing areas is poor immune responses to oral vaccines in children who have minimal maternal antibodies. Clinical studies of promising shigellosis vaccine candidates are urgently needed after confirmation of safety, immunogenicity, and protection in volunteer challenge models.
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Affiliation(s)
- Mi-Na Kweon
- Mucosal Immunology Section, Laboratory Science Division, International Vaccine Institute, Kwanak-Gu, Seoul, Korea.
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Riddle MS, Tribble DR. Reaching a consensus on management practices and vaccine development targets for mitigation of infectious diarrhoea among deployed US military forces. J Eval Clin Pract 2008; 14:266-74. [PMID: 18284518 DOI: 10.1111/j.1365-2753.2007.00848.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RATIONALE, AIMS AND OBJECTIVES This study is part of a research effort to identify and quantify factors related to the cost-effectiveness of a vaccine acquisition strategy to reduce the burden of infectious diarrhoea on US military personnel deployed overseas. Where evidence is lacking in the scientific literature, or considerable uncertainty exists, it is often necessary to develop best estimates with ranges of certainty. To this end, a modified 'Delphi' survey technique to obtain the best estimates for uncertain parameters including clinical care-seeking behaviour for acute diarrhoea, routine diarrhoea management in a deployed setting, and vaccine development time frames and costs were developed from a diverse panel of experts. METHODS The study was conducted in three survey iterations. During each iteration, participants were contacted and given 2-3 weeks to complete a web-based survey designed to ascertain estimates, ranges of variability, and level of certainty for these estimates. RESULTS In all, 25 of 43 solicited experts agreed to participate in the study. These included three (12%) experts who identified themselves primarily as being currently involved in Vaccine Industry, six (24%) Academic/Military Diarrheal Vaccine Development, five (20%) Military Product Acquisition, five (20%) Military Preventive Medicine, two (8%) Tropical/Travel Medicine and four (16%) Military Clinical Infectious Disease. Management practices in deployed military populations (for both provider and self-treatment) were consistent with recently published literature. Similar target time frames for vaccine licensure were established for Enterotoxigenic E. coli, Campylobacter, Shigella and Norovirus of around 9-11 years. Targets for vaccine efficacy appear to be lower than currently licensed travel vaccines (60-80%), and there was consensus on more conservative adverse event rates. CONCLUSIONS These data should prove useful to researchers and policy makers working in the area of vaccine acquisition for the US military and provide continued information on the gap in optimal travellers' diarrhoea management practices in a deployed setting.
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Affiliation(s)
- Mark S Riddle
- Infections Diseases Clinical Research Program, Preventive Medicine and Biometrics Department, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Diarrheal disease vaccines. Vaccines (Basel) 2008. [DOI: 10.1016/b978-1-4160-3611-1.50048-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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Sadorge C, Ndiaye A, Beveridge N, Frazer S, Giemza R, Jolly N, Johnson J, Liddy H, Cosgrove CA, Allavena P, Mantovani A, Béchet S, Fontaine-Thompson A, Griffin GE, Dupont F, Sansonetti PJ, Lewis DJM. Phase 1 clinical trial of live attenuated Shigella dysenteriae type-1 DeltaicsA Deltaent Deltafep DeltastxA:HgR oral vaccine SC599 in healthy human adult volunteers. Vaccine 2007; 26:978-87. [PMID: 18207287 DOI: 10.1016/j.vaccine.2007.11.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 11/06/2007] [Accepted: 11/11/2007] [Indexed: 11/24/2022]
Abstract
Twenty-eight adults received between 10(2) and 10(8)colony forming units of live Shigella dysenteriae type-1 vaccine SC599, attenuated by deletion of invasion (icsA), iron chelation (ent, fep) and shiga toxin A-subunit (stxA) genes, followed by ciprofloxacin on day 4. Dose-independent diarrhea or change in bowel habit was seen in 3 subjects, without dysentery, vaccinaemia or serious adverse events. Hematology and biochemical parameters were unchanged. Doses of 10(5) or greater induced dose-independent SD1 lipopolysaccharide-specific antibody secreting cell (ASC) responses. Geometric mean number of IgA ASCs per 10(6) PBMCs for 10(5), 10(6), 10(7) and 10(8) groups were respectively 41, 8.8, 26 and 8.5. Serum antibody responses were seen in three subjects. SC599 appears immunogenic with maximum tolerated dose greater than 10(8)CFU.
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Affiliation(s)
- Christine Sadorge
- Centre de Recherche Vaccinale et Biomédicale, Institut Pasteur, 75724 Paris Cedex 15, France
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Abstract
Type III secretion systems (T3SSs) are complex bacterial structures that provide gram-negative pathogens with a unique virulence mechanism enabling them to inject bacterial effector proteins directly into the host cell cytoplasm, bypassing the extracellular milieu. Although the effector proteins vary among different T3SS pathogens, common pathogenic mechanisms emerge, including interference with the host cell cytoskeleton to promote attachment and invasion, interference with cellular trafficking processes, cytotoxicity and barrier dysfunction, and immune system subversion. The activity of the T3SSs correlates closely with infection progression and outcome, both in animal models and in human infection. Therefore, to facilitate patient care and improve outcomes, it is important to understand the T3SS-mediated virulence processes and to target T3SSs in therapeutic and prophylactic development efforts.
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Levine MM, Kotloff KL, Barry EM, Pasetti MF, Sztein MB. Clinical trials of Shigella vaccines: two steps forward and one step back on a long, hard road. Nat Rev Microbiol 2007; 5:540-53. [PMID: 17558427 PMCID: PMC3771495 DOI: 10.1038/nrmicro1662] [Citation(s) in RCA: 266] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
More than 50 years of research has yielded numerous Shigella vaccine candidates that have exemplified both the promise of vaccine-induced prevention of shigellosis and the impediments to developing a safe and effective vaccine for widespread use, a goal that has yet to be attained. This Review discusses the most advanced strategies for Shigella vaccine development, the immune responses that are elicited following disease or vaccination, the factors that have accelerated or impeded Shigella vaccine development and our ideas for the way forward.
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MESH Headings
- Antibodies, Bacterial/blood
- Child, Preschool
- Clinical Trials as Topic
- Dysentery, Bacillary/epidemiology
- Dysentery, Bacillary/immunology
- Dysentery, Bacillary/microbiology
- Dysentery, Bacillary/prevention & control
- Humans
- Immunity, Cellular
- Infant
- Shigella/classification
- Shigella/immunology
- Shigella Vaccines/administration & dosage
- Shigella Vaccines/adverse effects
- Shigella Vaccines/immunology
- Vaccination
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/adverse effects
- Vaccines, Attenuated/immunology
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Affiliation(s)
- Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Parsa S, Pfeifer B. Engineering bacterial vectors for delivery of genes and proteins to antigen-presenting cells. Mol Pharm 2007; 4:4-17. [PMID: 17233543 DOI: 10.1021/mp0600889] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Bacterial vectors offer a biological route to gene and protein delivery with this article featuring delivery to antigen-presenting cells (APCs). Primarily in the context of immune stimulation against infectious disease or cancer, the goal of bacterially mediated delivery is to overcome the hurdles to effective macromolecule delivery. This review will present several bacterial vectors as macromolecule (protein or gene) delivery devices with both innate and acquirable (or engineered) biological features to facilitate delivery to APCs. The review will also present topics related to large-scale manufacture, storage, and distribution that must be considered if the bacterial delivery devices are ever to be used in a global market.
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Affiliation(s)
- Saba Parsa
- Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts 02155, USA
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Ranallo RT, Thakkar S, Chen Q, Venkatesan MM. Immunogenicity and characterization of WRSF2G11: a second generation live attenuated Shigella flexneri 2a vaccine strain. Vaccine 2006; 25:2269-78. [PMID: 17229494 DOI: 10.1016/j.vaccine.2006.11.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 11/21/2006] [Accepted: 11/30/2006] [Indexed: 10/23/2022]
Abstract
Recent clinical trials involving live attenuated Shigella vaccine strains SC602 and WRSS1 have revealed that deletion of the virG(icsA) gene dramatically reduces virulence in human volunteers. These strains can be given at low oral doses and induce a strong, and in some cases, protective immune responses. However, residual vaccine associated reactogenicity suggests that further attenuation is required. A recent clinical trial indicated that the set and sen enterotoxin genes contribute to the symptoms of fever and diarrhea observed with live Shigella vaccine strains. Based on these findings, a Shigella flexneri 2a vaccine candidate, WRSf2G11, with deletions in the virG(icsA), set and sen genes has been constructed using the lambda red recombinase system. The immunogenicity and protective efficacy of WRSf2G11 compares favorably with SC602 following either intranasal (IN) or ocular (OC) immunization of guinea pigs. Taken together, these data indicate that second generation virG-based Shigella vaccine strains which lack enterotoxin genes, such as WRSf2G11, will likely show lower levels of reactogenicity without hampering the robust immune responses achieved with previous live vaccines.
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Affiliation(s)
- Ryan T Ranallo
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
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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: 15] [Impact Index Per Article: 0.8] [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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Suzuki T, Yoshikawa Y, Ashida H, Iwai H, Toyotome T, Matsui H, Sasakawa C. High Vaccine Efficacy against Shigellosis of Recombinant NoninvasiveShigellaMutant That ExpressesYersiniaInvasin. THE JOURNAL OF IMMUNOLOGY 2006; 177:4709-17. [PMID: 16982910 DOI: 10.4049/jimmunol.177.7.4709] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Live attenuated Shigella vaccines elicit protective immune responses, but involve a potential risk of inducing a strong inflammatory reaction. The bacterial invasiveness that is crucial for Ag delivery causes inflammatory destruction of infected epithelial cells and proinflammatory cell death of infected macrophages. In this study, the noninvasive Shigella mutant DeltaipaB was equipped with Yersinia invasin protein, which has been shown to mediate bacterial invasion and targeting to M cells located in follicle-associated epithelium. Invasin-expressing DeltaipaB (DeltaipaB/inv) was internalized into epithelial cells and retained in the intraphagosomal space. DeltaipaB/inv did not induce necrotic cell death of infected macrophages nor cause symptomatic damage after intranasal vaccination of mice. DeltaipaB/inv was safer and more effective than the conventional live vaccine, DeltavirG. Infection by DeltaipaB/inv caused polymorphonuclear neutrophil infiltration in the lung, but did not induce production of large amounts of proinflammatory cytokines. We concluded that the low experimental morbidity and high vaccine efficacy of DeltaipaB/inv are primarily based on high protective immune responses, which may be enhanced by the polymorphonuclear neutrophil infiltration unaccompanied by tissue injury.
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Affiliation(s)
- Toshihiko Suzuki
- Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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von Seidlein L, Kim DR, Ali M, Lee H, Wang X, Thiem VD, Canh DG, Chaicumpa W, Agtini MD, Hossain A, Bhutta ZA, Mason C, Sethabutr O, Talukder K, Nair GB, Deen JL, Kotloff K, Clemens J. A multicentre study of Shigella diarrhoea in six Asian countries: disease burden, clinical manifestations, and microbiology. PLoS Med 2006; 3:e353. [PMID: 16968124 PMCID: PMC1564174 DOI: 10.1371/journal.pmed.0030353] [Citation(s) in RCA: 332] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Accepted: 06/21/2006] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The burden of shigellosis is greatest in resource-poor countries. Although this diarrheal disease has been thought to cause considerable morbidity and mortality in excess of 1,000,000 deaths globally per year, little recent data are available to guide intervention strategies in Asia. We conducted a prospective, population-based study in six Asian countries to gain a better understanding of the current disease burden, clinical manifestations, and microbiology of shigellosis in Asia. METHODS AND FINDINGS Over 600,000 persons of all ages residing in Bangladesh, China, Pakistan, Indonesia, Vietnam, and Thailand were included in the surveillance. Shigella was isolated from 2,927 (5%) of 56,958 diarrhoea episodes detected between 2000 and 2004. The overall incidence of treated shigellosis was 2.1 episodes per 1,000 residents per year in all ages and 13.2/1,000/y in children under 60 months old. Shigellosis incidence increased after age 40 years. S. flexneri was the most frequently isolated Shigella species (1,976/2,927 [68%]) in all sites except in Thailand, where S. sonnei was most frequently detected (124/146 [85%]). S. flexneri serotypes were highly heterogeneous in their distribution from site to site, and even from year to year. PCR detected ipaH, the gene encoding invasion plasmid antigen H in 33% of a sample of culture-negative stool specimens. The majority of S. flexneri isolates in each site were resistant to amoxicillin and cotrimoxazole. Ciprofloxacin-resistant S. flexneri isolates were identified in China (18/305 [6%]), Pakistan (8/242 [3%]), and Vietnam (5/282 [2%]). CONCLUSIONS Shigella appears to be more ubiquitous in Asian impoverished populations than previously thought, and antibiotic-resistant strains of different species and serotypes have emerged. Focusing on prevention of shigellosis could exert an immediate benefit first by substantially reducing the overall diarrhoea burden in the region and second by preventing the spread of panresistant Shigella strains. The heterogeneous distribution of Shigella species and serotypes suggest that multivalent or cross-protective Shigella vaccines will be needed to prevent shigellosis in Asia.
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Ranallo RT, Barnoy S, Thakkar S, Urick T, Venkatesan MM. Developing liveShigellavaccines using λ Red recombineering. ACTA ACUST UNITED AC 2006; 47:462-9. [PMID: 16872384 DOI: 10.1111/j.1574-695x.2006.00118.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Live attenuated Shigella vaccines have shown promise in inducing protective immune responses in human clinical trials and as carriers of heterologous antigens from other mucosal pathogens. In the past, construction of Shigella vaccine strains relied on classical allelic exchange systems to genetically engineer the bacterial genome. These systems require extensive in vitro engineering of long homologous sequences to create recombinant replication-defective plasmids or phage. Alternatively, the lambda red recombination system from bacteriophage facilitates recombination with as little as 40 bp of homologous DNA. The process, referred to as recombineering, typically uses an inducible lambda red operon on a temperature-sensitive plasmid and optimal transformation conditions to integrate linear antibiotic resistance cassettes flanked by homologous sequences into a bacterial genome. Recent advances in recombineering have enabled modification of genomic DNA from bacterial pathogens including Salmonella, Yersinia, enteropathogenic Escherichia coli, or enterohemorrhagic E. coli and Shigella. These advances in recombineering have been used to systematically delete virulence-associated genes from Shigella, creating a number of isogenic strains from multiple Shigella serotypes. These strains have been characterized for attenuation using both in vivo and in vitro assays. Based on this data, prototypic Shigella vaccine strains containing multiple deletions in virulence-associated genes have been generated.
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Affiliation(s)
- Ryan T Ranallo
- Department of Enteric Infections, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Favre D, Viret JF. Biosafety evaluation of recombinant live oral bacterial vaccines in the context of European regulation. Vaccine 2006; 24:3856-64. [PMID: 16115705 DOI: 10.1016/j.vaccine.2005.07.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Live bacterial vaccines represent a highly valid preventive strategy in the fight against infectious disease. However, the road from research to market is peppered with hurdles, one of which is the requirement for high biosafety characteristics, which the candidate vaccine has to display. In Europe, the European Agency for the evaluation of medicinal products (EMEA) is the relevant authority regulating the licensure of genetically engineered vaccines. For this purpose, the agency may rely on several directives and guidelines defined in the past 15 years. As for live vaccines containing genetically modified organisms (GMOs) susceptible to be released into the environment, Directive 2001/18/EC determines the framework and principles of an environmental risk assessment (ERA) process, the results of which constitute an important section of the vaccine registration package submitted to registration authorities. In this article, we address the implications of current European regulations for the approval of live oral bacterial vaccines with emphasis on the assessment of potential risks associated with environmental release. Biosafety aspects of already registered and some promising live bacterial vaccine strains will be briefly discussed.
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Affiliation(s)
- Didier Favre
- Berna Biotech Ltd., Research Rehhagstrasse 79, 3018 Berne, Switzerland
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Ranallo RT, Fonseka CP, Cassels F, Srinivasan J, Venkatesan MM. Construction and characterization of bivalent Shigella flexneri 2a vaccine strains SC608(pCFAI) and SC608(pCFAI/LTB) that express antigens from enterotoxigenic Escherichia coli. Infect Immun 2005; 73:258-67. [PMID: 15618162 PMCID: PMC538972 DOI: 10.1128/iai.73.1.258-267.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
An invasive strain of Shigella flexneri 2a (SC608) has been developed as a vector for the expression and delivery of heterologous antigens. SC608 is an aspartate semialdehyde dehydrogenase (asd) derivative of SC602 (icsA iuc), a well-characterized live attenuated vaccine strain which has undergone several clinical trials in human volunteers. When administered orally at a single 10(4) (CFU) dose, SC602 is both immunogenic and efficacious against shigellosis. Using asd-based plasmid vectors, we designed SC608 to express the enterotoxigenic Escherichia coli (ETEC) fimbrial subunit CfaB (CFA/I structural subunit) alone or in combination with the E. coli B subunit of heat-labile enterotoxin (LTB). The expression of each heterologous protein in SC608 was verified by immunoblot analysis. Each strain was comparable to the parent strain, SC602, in a HeLa cell invasion assay. After intranasal immunizations of guinea pigs, serum and mucosal immune responses were detected against both Shigella lipopolysaccharide and heterologous ETEC antigens by enzyme-linked immunosorbent assay and ELISPOT analysis. All immunized animals were subsequently protected against a challenge with wild-type S. flexneri 2a in a keratoconjunctivitis Sereny test. Serum antibodies generated against LTB and CfaB demonstrated antitoxin and agglutination activities, respectively. These results suggest that CfaB and LTB expressed in SC608 retain important conformational epitopes that are required for the generation of antibodies that have functional activities. These initial experiments demonstrate that a fully invasive Shigella vaccine strain can be engineered to deliver antigens from other diarrheal pathogens.
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Affiliation(s)
- Ryan T Ranallo
- Department of Enteric Infections, Division of Communicable Disease and Immunology, Walter Reed Army Institute of Research, 503 Robert Grant Ave., Silver Spring, MD 20910, USA
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Antigen Delivery Systems II: Development of Live Recombinant Attenuated Bacterial Antigen and DNA Vaccine Delivery Vector Vaccines. Mucosal Immunol 2005. [DOI: 10.1016/b978-012491543-5/50060-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Vaccines against Infections Caused by Salmonella, Shigella, and Pathogenic Escherichia coli. EcoSal Plus 2004; 1. [PMID: 26443352 DOI: 10.1128/ecosalplus.8.8.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Infectious diseases represent one of the most common causes of death worldwide, with the enteropathogenic bacteria Salmonella and Shigella and pathogenic Escherichia coli being among the most detrimental. Currently, vaccination represents the preferred method of preventing such infections. For stimulating the adaptive immune response, immunizations are frequently based on formulations which include inactivated whole-cell vaccines, live attenuated vaccines, or subunit vaccines. These can be administered via a parenteral or mucosal route, the latter having the advantage that it most closely mimics the actual course of infection. In addition to the type of vaccine and method of application, important consideration needs to be paid to safety, efficacy, and cost, which are often major bottlenecks in the successful implementation of vaccines. In this chapter we take a limited look at the history surrounding vaccinations involving Salmonella, Shigella, and pathogenic E. coli. Salmonella infections, which can lead to typhoid fever, are becoming increasing difficult to treat with antibiotics due to multi-drug-resistant strains. At present, the parenteral Vi-based subunit vaccines and the live attenuated oral vaccine Ty21a have proven to be the vaccines of choice, with high levels of protective efficacy and limited side effects. Shigella infections are responsible for the diarrheal disease shigellosis. Various live and nonliving mucosal and parenteral vaccines have been tested, with the most promising candidates evolving around those that stimulate the production of O-antigen-specific antibodies. Pathogenic Escherichia coli infections can lead to severe diseases due to the bacterium's production of several specific toxins. Vaccines against this bacterium target its toxins, as well as surface-exposed antigens, all of which have been found to be effective as immunogens.
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Affiliation(s)
- Camille N Kotton
- Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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Jennison AV, Verma NK. Shigella flexneri infection: pathogenesis and vaccine development. FEMS Microbiol Rev 2004; 28:43-58. [PMID: 14975529 DOI: 10.1016/j.femsre.2003.07.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2003] [Revised: 07/25/2003] [Accepted: 07/30/2003] [Indexed: 02/08/2023] Open
Abstract
Shigella flexneri is a gram-negative bacterium which causes the most communicable of bacterial dysenteries, shigellosis. Shigellosis causes 1.1 million deaths and over 164 million cases each year, with the majority of cases occurring in the children of developing nations. The pathogenesis of S. flexneri is based on the bacteria's ability to invade and replicate within the colonic epithelium, which results in severe inflammation and epithelial destruction. The molecular mechanisms used by S. flexneri to cross the epithelial barrier, evade the host's immune response and enter epithelial cells have been studied extensively in both in vitro and in vivo models. Consequently, numerous virulence factors essential to bacterial invasion, intercellular spread and the induction of inflammation have been identified in S. flexneri. The inflammation produced by the host has been implicated in both the destruction of the colonic epithelium and in controlling and containing the Shigella infection. The host's humoral response to S. flexneri also appears to be important in protecting the host, whilst the role of the cellular immune response remains unclear. The host's immune response to shigellosis is serotype-specific and protective against reinfection by the same serotype, making vaccination a possibility. Since the 1940s vaccines for S. flexneri have been developed with little success, however, the growing understanding of S. flexneri's pathogenesis and the host's immune response is assisting in the generation of more refined vaccine strategies. Current research encompasses a variety of vaccine types, which despite disparity in their efficacy and safety in humans represent promising progress in S. flexneri vaccine development.
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Affiliation(s)
- Amy V Jennison
- Faculty of Science, School of Biochemistry and Molecular Biology, The Australian National University, Canberra, ACT 0200, Australia
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Svennerholm AM, Steele D. Microbial-gut interactions in health and disease. Progress in enteric vaccine development. Best Pract Res Clin Gastroenterol 2004; 18:421-45. [PMID: 15123079 DOI: 10.1016/j.bpg.2003.11.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Enteric infections resulting in diarrhoea are among the most important causes of morbidity and mortality, particularly in children in developing countries. They are also a common cause of disease among travellers to Africa, Asia and Latin America. Recently, effective, live and inactivated oral and parenteral vaccines against some of the most severe enteric infections-cholera and typhoid fever-have been licensed in several countries. Different candidate vaccines against rotavirus, Shigella and ETEC diarrhoea have also been developed and tested for safety and immunogenicity in developed as well as in developing countries. The protective efficacy of several of these vaccines has also been tested, either in human volunteer challenge studies or in field trials. In this chapter we describe the properties and availability of the recently licensed vaccines and present an update on the diverse efforts being made to achieve new or improved vaccines against the most prevalent enteropathogens.
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Affiliation(s)
- Ann-Mari Svennerholm
- Department of Medical Microbiology and Immunology, and Göteborg University Vaccine Institute (GUVAX), Göteborg University, P.O. Box 435, Göteborg S-405 30, Sweden.
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Katz DE, Coster TS, Wolf MK, Trespalacios FC, Cohen D, Robins G, Hartman AB, Venkatesan MM, Taylor DN, Hale TL. Two studies evaluating the safety and immunogenicity of a live, attenuated Shigella flexneri 2a vaccine (SC602) and excretion of vaccine organisms in North American volunteers. Infect Immun 2004; 72:923-30. [PMID: 14742537 PMCID: PMC321603 DOI: 10.1128/iai.72.2.923-930.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report the first community-based evaluation of Shigella flexneri 2a strain SC602, a live, oral vaccine strain attenuated by deletion of the icsA (virG) plasmid virulence gene, given at 10(4) CFU. The primary objectives of this trial were to determine the safety and immunogenicity of the vaccine and to determine the duration of colonization. Four of 34 volunteers experienced transient fevers, and three reported diarrhea during the first 3 days of the study. Half of the volunteers mounted a positive serum immunoglobulin A (IgA) response to S. flexneri lipopolysaccharide. All but one of the volunteers excreted the vaccine in their stools for 1 to 33 days, and this excretion was often intermittent. Data from the community-based study were supplemented with an inpatient trial in which three volunteers received 10(3) and nine received 10(4) CFU. All volunteers who received 10(3) CFU excreted SC602 and had an IgA antibody-secreting cell response. Two of these had a serum IgA response. Six of the nine volunteers who received 10(4) CFU excreted SC602. One vaccinee had a transient fever and two met the definition of diarrhea. Six volunteers that received 10(4) CFU had an antibody-secreting cell response, and four had a serum IgA response. SC602 has now been tested at 10(4) CFU in a total of 58 volunteers. The cumulative results of these clinical trials, reported here and previously (Coster et al., Infect. Immun. 67:3437-3443, 1999), have demonstrated that SC602 is a substantially attenuated candidate vaccine that can evoke protection against the most severe symptoms of shigellosis in a stringent human challenge model of disease.
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Affiliation(s)
- David E Katz
- Department of Enteric Infections, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910-7500, USA
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