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Lu T, Das S, Howlader DR, Picking WD, Picking WL. Shigella Vaccines: The Continuing Unmet Challenge. Int J Mol Sci 2024; 25:4329. [PMID: 38673913 PMCID: PMC11050647 DOI: 10.3390/ijms25084329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Shigellosis is a severe gastrointestinal disease that annually affects approximately 270 million individuals globally. It has particularly high morbidity and mortality in low-income regions; however, it is not confined to these regions and occurs in high-income nations when conditions allow. The ill effects of shigellosis are at their highest in children ages 2 to 5, with survivors often exhibiting impaired growth due to infection-induced malnutrition. The escalating threat of antibiotic resistance further amplifies shigellosis as a serious public health concern. This review explores Shigella pathology, with a primary focus on the status of Shigella vaccine candidates. These candidates include killed whole-cells, live attenuated organisms, LPS-based, and subunit vaccines. The strengths and weaknesses of each vaccination strategy are considered. The discussion includes potential Shigella immunogens, such as LPS, conserved T3SS proteins, outer membrane proteins, diverse animal models used in Shigella vaccine research, and innovative vaccine development approaches. Additionally, this review addresses ongoing challenges that necessitate action toward advancing effective Shigella prevention and control measures.
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Affiliation(s)
- Ti Lu
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - Sayan Das
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA;
| | - Debaki R. Howlader
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - William D. Picking
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
| | - Wendy L. Picking
- Department of Veterinary Pathobiology and Bond Life Science Center, University of Missouri, Columbia, MO 65201, USA; (D.R.H.); (W.D.P.)
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Khalouie F, Mousavi SL, Nazarian S, Amani J, Pourfarzam P. Immunogenic evaluation of chimeric recombinant protein against ETEC, EHEC and Shigella. MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2017; 6:101-112. [PMID: 29071279 PMCID: PMC5640892 DOI: 10.22099/mbrc.2017.4081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Diarrheal diseases still remain health problem worldwide and out of many bacteria responsible for, Shigella and pathogenic Escherichia cause the most diarrheas in the world. Shigellacause bacterial dysenteries and shigellosis through invasion where the most effective proteins for pathogenesis is Ipac. Critical virulence protein for ETEC infection is CFA/I with two subunits called cfab and cfae. . Attachment of EHEC is the main step of infection and the protein Intimin plays the key role in this function. Protection against the vast majority of responsible pathogens of diarrheas requires development of the combination vaccine against Shigella, ETEC and EHEC. In the present study, a multisubunitprotein (CII) containing immunologically significant parts of CfaB, IpaC and Intimin was designed. The chimeric gene (CII) was codon optimized and analyzed with different bioinformatic servers, then synthesized and expressed in E. coli. Mice, Guinea pig and, Caco-2 Cell line were used as challenge models for EHEC, shigella and ETEC respectively. The chimeric protein induced significant immune response and therefore could be a suitable vaccine candidate against these three pathogens.
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Affiliation(s)
- Farzane Khalouie
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Seyed Latif Mousavi
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biology, Faculty of Sciences, Imam Hossein University, Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Poune Pourfarzam
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
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BangaSingh KK, Nisha M, Lau HY, Ravichandran M, Salleh MZ. Alteration in apyrase enzyme attenuated virulence of Shigella flexneri. Microb Pathog 2015; 91:123-8. [PMID: 26706344 DOI: 10.1016/j.micpath.2015.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 12/01/2015] [Accepted: 12/01/2015] [Indexed: 10/22/2022]
Abstract
Virulence of Shigella is attributed to the genes presence in chromosome or in the megaplasmid. The apy gene which is located in the megaplasmid of Shigella species encodes for apyrase enzyme, a pathogenesis-associated enzyme causing mitochondrial damage and host cell death. In this study we constructed an apy mutant of Shigella flexneri by insertional activation using a kanamycin resistant gene cassette. The wild type apy gene of S. flexneri 2a was PCR amplified, cloned and mutated with insertion of kanamycin resistant gene cassette (aphA). The mutated construct (apy: aphA) was subcloned into a conjugative suicidal vector (pWM91) at the unique Sma1 and Sac1 sites. The mutation of the wild apy gene in the construct was confirmed by DNA sequencing. The mutated construct was introduced into wild type S. flexneri 2a by conjugation with Escherichia coli. After undergoing homologous recombination, the wild apy gene was deleted from the construct using the sucrose selection method. Non-functional activity of the apyrase enzyme in the constructed strain by colorimetric test indicated the successful mutation of the apyrase enzyme. This strain with mutated apy gene was evaluated for its protective efficacy using the guinea pig keratoconjunctivitis model. The strain was Sereny negative and it elicited a significant protection following challenge with wild S. flexneri strain. This apy mutant strain will form a base for the development of a vaccine target for shigellosis.
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Affiliation(s)
- Kirnpal Kaur BangaSingh
- Department of Medical Microbiology & Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia.
| | - Mehru Nisha
- Department of Medical Microbiology & Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia
| | - Hut Yee Lau
- Reconstructive Sciences Unit, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia
| | | | - Mohd Zaki Salleh
- Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Selangor, Malaysia
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O'Ryan M, Vidal R, del Canto F, Carlos Salazar J, Montero D. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni. Hum Vaccin Immunother 2015; 11:601-19. [PMID: 25715096 DOI: 10.1080/21645515.2015.1011578] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral(®)), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed.
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Key Words
- CFU, colony-forming units
- CFs, colonization factors
- CT, cholera toxin
- CT-B cholera toxin B subunit
- Campylobacter
- CtdB, cytolethal distending toxin subunit B
- E. coli
- EHEC
- EPEC, enteropathogenic E. coli
- ETEC
- ETEC, enterotoxigenic E. coli
- GEMS, Global enterics multicenter study
- HUS, hemolytic uremic syndrome
- IM, intramuscular
- IgA, immunoglobulin A
- IgG, immunoglobulin G
- IgM, immunoglobulin M
- LEE, locus of enterocyte effacement
- LPS, lipopolysaccharide
- LT, heat labile toxin
- LT-B
- OMV, outer membrane vesicles
- ST, heat stable toxin
- STEC
- STEC, shigatoxin producing E. coli
- STh, human heat stable toxin
- STp, porcine heat stable toxin
- Salmonella
- Shigella
- Stx, shigatoxin
- TTSS, type III secretion system
- V. cholera
- WHO, World Health Organization
- acute diarrhea
- dmLT, double mutant heat labile toxin
- enteric pathogens
- enterohemorrhagic E. coli
- gastroenteritis
- heat labile toxin B subunit
- norovirus
- rEPA, recombinant exoprotein A of Pseudomonas aeruginosa
- rotavirus
- vaccines
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Affiliation(s)
- Miguel O'Ryan
- a Microbiology and Mycology Program; Institute of Biomedical Sciences; Faculty of Medicine; Universidad de Chile; Santiago, Chile
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Vongsawan AA, Kapatral V, Vaisvil B, Burd H, Serichantalergs O, Venkatesan MM, Mason CJ. The genome of Shigella dysenteriae strain Sd1617 comparison to representative strains in evaluating pathogenesis. FEMS Microbiol Lett 2015; 362:fnv011. [PMID: 25743074 PMCID: PMC4445032 DOI: 10.1093/femsle/fnv011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We sequenced and analyzed Shigella dysenteriae strain Sd1617 serotype 1 that is widely used as model strain for vaccine design, trials and research. A combination of next-generation sequencing platforms and assembly yielded two contigs representing a chromosome size of 4.34 Mb and the large virulence plasmid of 177 kb. This genome sequence is compared with other Shigella genomes in order to understand gene complexity and pathogenic factors. The Shigella dysenteriae strain Sd1617 serotype 1 has been sequenced and analyzed. It is widely used as model strain for vaccine design, trials and research. A combination of next-generation sequencing platforms and assembly yielded two contigs representing a chromosome size of 4.34 Mb and the large virulence plasmid of 177 kb.
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Affiliation(s)
- Ajchara A Vongsawan
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | | | | | | | - Oralak Serichantalergs
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - Malabi M Venkatesan
- Walter Reed Army Institute of Research, Division of Bacterial and Rickettsial Diseases, Silver Spring, MD 20910, USA
| | - Carl J Mason
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
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Chowdhury FM, Rahman MZ, Khan SI, Ahsan CR, Birkeland NK. An environmental Escherichia albertii strain, DM104, induces protective immunity to Shigella dysenteriae in guinea pig eye model. Curr Microbiol 2014; 68:642-7. [PMID: 24452425 DOI: 10.1007/s00284-014-0522-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 11/28/2013] [Indexed: 10/25/2022]
Abstract
The environmental Escherichia albertii strain DM104, which cross-reacts serologically with Shigella dysenteriae was assessed for pathogenic properties, immunogenicity, and protective efficacy in different animal models to evaluate it as a vaccine candidate against S. dysenteriae, which causes the severe disease, shigellosis. The DM104 isolate was found to be non-invasive and did not produce any entero- or cyto-toxins. The strain also showed negative results in the mouse lethal activity assay. The non-pathogenic DM104 strain gave, however, a high protective efficacy as an ocularly administered vaccine in the guinea pig eye model against S. dysenteriae type 4 challenge. It also induced a high titer of serum IgG against S. dysenteriae type 4 whole cell lysate and lipopolysaccharide. Taken together, all these results indicate a good potential for the use of the DM104 as a live vaccine candidate against shigellosis.
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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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Fiorentino M, Levine MM, Sztein MB, Fasano A. Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release. PLoS One 2014; 9:e85211. [PMID: 24416363 PMCID: PMC3887025 DOI: 10.1371/journal.pone.0085211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/27/2013] [Indexed: 01/22/2023] Open
Abstract
Bacterial dysentery due to Shigella species is a major cause of morbidity and mortality worldwide. The pathogenesis of Shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. Although the mechanisms of pathogenesis of Shigella in the colon have been extensively studied, little is known on the effect of wild-type Shigella on the small intestine and the role of the host response in the development of the disease. Moreover, to the best of our knowledge no studies have described the effects of apically administered Shigella flexneri 2a and S. dysenteriae 1 vaccine strains on human small intestinal enterocytes. The aim of this study was to assess the coordinated functional and immunological human epithelial responses evoked by strains of Shigella and candidate vaccines on small intestinal enterocytes. To model the interactions of Shigella with the intestinal mucosa, we apically exposed monolayers of human intestinal Caco2 cells to increasing bacterial inocula. We monitored changes in paracellular permeability, examined the organization of tight-junctions and the pro-inflammatory response of epithelial cells. Shigella infection of Caco2 monolayers caused severe mucosal damage, apparent as a drastic increase in paracellular permeability and disruption of tight junctions at the cell-cell boundary. Secretion of pro-inflammatory IL-8 was independent of epithelial barrier dysfunction. Shigella vaccine strains elicited a pro-inflammatory response without affecting the intestinal barrier integrity. Our data show that wild-type Shigella infection causes a severe alteration of the barrier function of a small intestinal cell monolayer (a proxy for mucosa) and might contribute (along with enterotoxins) to the induction of watery diarrhea. Diarrhea may be a mechanism by which the host attempts to eliminate harmful bacteria and transport them from the small to the large intestine where they invade colonocytes inducing a strong inflammatory response.
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Affiliation(s)
- Maria Fiorentino
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Myron M. Levine
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Marcelo B. Sztein
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
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10
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Camacho AI, Irache JM, Gamazo C. Recent progress towards development of a Shigella vaccine. Expert Rev Vaccines 2013; 12:43-55. [PMID: 23256738 DOI: 10.1586/erv.12.135] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The burden of dysentery due to shigellosis among children in the developing world is still a major concern. A safe and efficacious vaccine against this disease is a priority, since no licensed vaccine is available. This review provides an update of vaccine achievements focusing on subunit vaccine strategies and the forthcoming strategies surrounding this approach. In particular, this review explores several aspects of the pathogenesis of shigellosis and the elicited immune response as being the basis of vaccine requirements. The use of appropriate Shigella antigens, together with the right adjuvants, may offer safety, efficacy and more convenient delivery methods for massive worldwide vaccination campaigns.
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11
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Abstract
Renewed awareness of the substantial morbidity and mortality that Shigella infection causes among young children in developing countries, combined with technological innovations in vaccinology, has led to the development of novel vaccine strategies in the past 5 years. Along with advancement of classic vaccines in clinical trials and new sophisticated measurements of immunological responses, much new data has been produced, lending promise to the potential for production of safe and effective Shigella vaccines. Herein, we review the latest progress in Shigella vaccine development within the framework of persistent obstacles.
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12
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Live attenuated Shigella dysenteriae type 1 vaccine strains overexpressing shiga toxin B subunit. Infect Immun 2011; 79:4912-22. [PMID: 21969003 DOI: 10.1128/iai.05814-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigella dysenteriae serotype 1 (S. dysenteriae 1) is unique among the Shigella species and serotypes in the expression of Shiga toxin which contributes to more severe disease sequelae and the ability to cause explosive outbreaks and pandemics. S. dysenteriae 1 shares characteristics with other Shigella species, including the capability of causing clinical illness with a very low inoculum (10 to 100 CFU) and resistance to multiple antibiotics, underscoring the need for efficacious vaccines and therapeutics. Following the demonstration of the successful attenuating capacity of deletion mutations in the guaBA operon in S. flexneri 2a vaccine strains in clinical studies, we developed a series of S. dysenteriae 1 vaccine candidates containing the fundamental attenuating mutation in guaBA. All strains are devoid of Shiga toxin activity by specific deletion of the gene encoding the StxA subunit, which encodes enzymatic activity. The StxB subunit was overexpressed in several derivatives by either plasmid-based constructs or chromosomal manipulation to include a strong promoter. All strains are attenuated for growth in vitro in the HeLa cell assay and for plaque formation and were safe in the Serény test and immunogenic in the guinea pigs. Each strain induced robust serum and mucosal anti-S. dysenteriae 1 lipopolysaccharide (LPS) responses and protected against wild-type challenge. Two strains engineered to overexpress StxB induced high titers of Shiga toxin neutralizing antibodies. These candidates demonstrate the potential for a live attenuated vaccine to protect against disease caused by S. dysenteriae 1 and potentially to protect against the toxic effects of other Shiga toxin 1-expressing pathogens.
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Cai X, Zhang J, Chen M, Wu Y, Wang X, Chen J, Zhang J, Shen X, Qu D, Jiang H. The effect of the potential PhoQ histidine kinase inhibitors on Shigella flexneri virulence. PLoS One 2011; 6:e23100. [PMID: 21853073 PMCID: PMC3154276 DOI: 10.1371/journal.pone.0023100] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 07/11/2011] [Indexed: 02/03/2023] Open
Abstract
PhoQ/PhoP is an important two-component system that regulates Shigella virulence. We explored whether the PhoQ/PhoP system is a promising target for new antibiotics against S. flexneri infection. By using a high-throughput screen and enzymatic activity coupled assay, four compounds were found as potential PhoQ inhibitors. These compounds not only inhibited the activity of SF-PhoQc autophosphorylation but also displayed high binding affinities to the SF-PhoQc protein in the Surface Plasmon Resonance response. A S. flexneri cell invasion assay showed that three of these potential PhoQ inhibitors inhibit the invasion of HeLa cells by S. flexneri 9380. In a Mouse Sereny test, mice inoculated with S. flexneri 9380 pre-treated with the potential PhoQ inhibitors 1, 2, 3 or 4 displayed no inflammation, whereas mice inoculated with S. flexneri 9380 alone displayed severe keratoconjunctival inflammation. All four potential PhoQ inhibitors showed no significant cytotoxicity or hemolytic activity. These data suggest that the four potential PhoQ inhibitors inhibited the virulence of S. flexneri and that PhoQ/PhoP is a promising target for the development of drugs against S. flexneri infection.
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Affiliation(s)
- Xia Cai
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jian Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Mingliang Chen
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xueqing Wang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jiayu Chen
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Junqin Zhang
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xu Shen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, Institute of Medical Microbiology and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- * E-mail: (DQ); (HJ)
| | - Hualiang Jiang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (DQ); (HJ)
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14
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Shigella sonnei vaccine candidates WRSs2 and WRSs3 are as immunogenic as WRSS1, a clinically tested vaccine candidate, in a primate model of infection. Vaccine 2011; 29:6371-8. [DOI: 10.1016/j.vaccine.2011.04.115] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 04/28/2011] [Indexed: 01/24/2023]
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15
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Shipley ST, Panda A, Khan AQ, Kriel EH, Jr MM, Livio S, Nataro JP, Levine MM, Sztein MB, DeTolla LJ. A challenge model for Shigella dysenteriae 1 in cynomolgus monkeys (Macaca fascicularis). Comp Med 2010; 60:54-61. [PMID: 20158950 PMCID: PMC2826086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 09/05/2009] [Accepted: 11/09/2009] [Indexed: 05/28/2023]
Abstract
Shigella dysenteriae type 1 can cause devastating pandemics with high case fatality rates; a vaccine for Shigella is unavailable currently. Because of the risks associated with performing challenge studies with wild-type S. dysenteriae 1 in human clinical trials to advance vaccine development, an improved nonhuman primate model is needed urgently. In the present study, cynomolgus macaques (Macaca fascicularis) were challenged with various doses of S. dysenteriae 1 strain 1617 to establish a dose that would produce shigellosis. Further, different routes of delivery of S. dysenteriae 1 were compared to establish the most appropriate route for infection. Animals receiving 10(11) cfu S. dysenteriae 1 intragastrically consistently developed signs of shigellosis characterized by the onset of diarrhea and dysentery within 2 to 3 d. Administration of as many as 10(9) cfu S. dysenteriae 1 intraduodenally did not elicit signs characteristic of infection in macaques despite fecal shedding of bacteria for as long as 10 d. S. dysenteriae 1 administered intraduodenally at 10(9) cfu or intragastrically at 10(11) cfu elicited robust IgG and IgA antibody responses to LPS. We have developed a reliable challenge model of infection with wild-type S. dysenteriae 1 in cynomolgus macaques that reproducibly induces disease and elicits robust immune responses. We believe that this animal model may provide unique insights into the immunologic mechanisms of protection to S. dysenteriae 1 infection and in advancing development of a vaccine against shigellosis.
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Affiliation(s)
- Steven T Shipley
- Comparative Medicine Program, Department of Pathology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Aruna Panda
- Comparative Medicine Program, Department of Pathology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Abdul Q Khan
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Edwin H Kriel
- Comparative Medicine Program, Department of Pathology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Milton Maciel Jr
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Sofie Livio
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - James P Nataro
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Myron M Levine
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Marcelo B Sztein
- Center for Vaccine Development, Division of Infectious Diseases and Tropical Pediatrics, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Louis J DeTolla
- Comparative Medicine Program, Department of Pathology, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Medicine (Infectious Diseases) and Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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16
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Virulence, inflammatory potential, and adaptive immunity induced by Shigella flexneri msbB mutants. Infect Immun 2009; 78:400-12. [PMID: 19884336 DOI: 10.1128/iai.00533-09] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The ability of genetically detoxified lipopolysaccharide (LPS) to stimulate adaptive immune responses is an ongoing area of investigation with significant consequences for the development of safe and effective bacterial vaccines and adjuvants. One approach to genetic detoxification is the deletion of genes whose products modify LPS. The msbB1 and msbB2 genes, which encode late acyltransferases, were deleted in the Shigella flexneri 2a human challenge strain 2457T to evaluate the virulence, inflammatory potential, and acquired immunity induced by strains producing underacylated lipid A. Consistent with a reduced endotoxic potential, S. flexneri 2a msbB mutants were attenuated in an acute mouse pulmonary challenge model. Attenuation correlated with decreases in the production of proinflammatory cytokines and in chemokine release without significant changes in lung histopathology. The levels of specific proinflammatory cytokines (interleukin-1beta [IL-1beta], macrophage inflammatory protein 1alpha [MIP-1alpha], and tumor necrosis factor alpha [TNF-alpha]) were also significantly reduced after infection of mouse macrophages with either single or double msbB mutants. Surprisingly, the msbB double mutant displayed defects in the ability to invade, replicate, and spread within epithelial cells. Complementation restored these phenotypes, but the exact nature of the defects was not determined. Acquired immunity and protective efficacy were also assayed in the mouse lung model, using a vaccination-challenge study. Both humoral and cellular responses were generally robust in msbB-immunized mice and afforded significant protection from lethal challenge. These data suggest that the loss of either msbB gene reduces the endotoxicity of Shigella LPS but does not coincide with a reduction in protective immune responses.
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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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McKenzie R, Venkatesan MM, Wolf MK, Islam D, Grahek S, Jones AM, Bloom A, Taylor DN, Hale TL, Bourgeois AL. Safety and immunogenicity of WRSd1, a live attenuated Shigella dysenteriae type 1 vaccine candidate. Vaccine 2008; 26:3291-6. [DOI: 10.1016/j.vaccine.2008.03.079] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2008] [Revised: 03/26/2008] [Accepted: 03/31/2008] [Indexed: 10/22/2022]
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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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20
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Collins TA, Barnoy S, Baqar S, Ranallo RT, Nemelka KW, Venkatesan MM. Safety and colonization of two novel VirG(IcsA)-based live Shigella sonnei vaccine strains in rhesus macaques (Macaca mulatta). Comp Med 2008; 58:88-94. [PMID: 19793462 PMCID: PMC2703165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 11/21/2007] [Accepted: 11/29/2007] [Indexed: 05/28/2023]
Abstract
Shigella are gram-negative bacterium that cause bacillary dysentery (shigellosis). Symptoms include diarrhea and discharge of bloody mucoid stools, accompanied by severe abdominal pain, nausea, vomiting, malaise, and fever. Persons traveling to regions with poor sanitation and crowded conditions become particularly susceptible to shigellosis. Currently a vaccine for Shigella has not been licensed in the United States, and the organism quickly becomes resistant to medications. During the past 10 y, several live attenuated oral Shigella vaccines, including the strain WRSS1, have been tested in humans with considerable success. These Phase I vaccines lack the gene for the protein VirG also known as IcsA, which enables the organism to disseminate in the host target tissue. However, 5% to 20% of the vaccinated volunteers developed mild fever and brief diarrhea, and the removal of additional virulence-associated genes from the vaccine strain may reduce or eliminate these side effects. We administered 2 Shigella sonnei vaccines, WRSs2 and WRSs3, along with WRSS1 to compare their rates of colonization and clinical safety in groups of 5 rhesus macaques. The primate model provides the most physiologically relevant animal system to test the validity and efficacy of vaccine candidates. In this pilot study using a gastrointestinal model of infection, the vaccine candidates WRSs2 and WRSs3, which have additional deletions in the enterotoxin and LPS modification genes, provided better safety and comparable immunogenicity to those of WRSS1.
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Affiliation(s)
- Todd A Collins
- The Walter Reed Army Institute of Research, Naval Medical Research Center, Silver Spring, MD, USA.
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21
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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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Osorio M, Bray MD, Walker RI. Vaccine potential for inactivated shigellae. Vaccine 2007; 25:1581-92. [PMID: 17178431 DOI: 10.1016/j.vaccine.2006.11.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 11/01/2006] [Accepted: 11/06/2006] [Indexed: 11/18/2022]
Abstract
We used human monocyte-derived dendritic cells (DC) and Balb/c mice as models to establish the immunogenic and protective potential of formalin-inactivated Shigella spp. Incubation of DC with inactivated or live bacteria induced DC maturation and cytokine release. Mice immunized orally or intranasally with killed S. flexneri, S. sonnei, or S. dysenteriae developed IgG and fecal IgA titers to the homologous LPS. Following respiratory challenge with the live homologous organisms, 80-100% survival was seen in all vaccinated groups compared to negligible survival in mice given PBS. Oral or intranasal immunization with an inactivated S. flexneri 2a strain (CVD1203) expressing the CFA/I and CS3 antigens of enterotoxigenic Escherichia coli induced IgG responses to both heterologous antigens. These in vivo and in vitro data indicate that inactivated shigellae retain the ability to interact effectively with key antigen presenting cells and induce protective immune responses in mice.
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Affiliation(s)
- Manuel Osorio
- Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852-1448, United States
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Oaks EV, Turbyfill KR. Development and evaluation of a Shigella flexneri 2a and S. sonnei bivalent invasin complex (Invaplex) vaccine. Vaccine 2005; 24:2290-301. [PMID: 16364513 DOI: 10.1016/j.vaccine.2005.11.040] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 10/24/2005] [Accepted: 11/18/2005] [Indexed: 11/19/2022]
Abstract
Over 160 million cases of shigellosis occur annually worldwide, with the two most prevalent species being Shigella flexneri and S. sonnei. Protective immunity against Shigella infection is primarily directed at the lipopolysaccharide (LPS) of the homologous serotype, so it may be necessary to combine monovalent vaccines for multiple Shigella serotypes to construct a multivalent vaccine against predominant serotypes. Recently, we described a subcellular vaccine isolated from virulent S. flexneri, consisting of proteins (including the invasins IpaB and IpaC) and LPS, that protected mice and guinea pigs from homologous challenge. In the present study, a bivalent Invaplex vaccine consisting of S. flexneri 2a and S. sonnei Invaplex was used to intranasally immunize mice and guinea pigs to determine the bivalent vaccine's immunogenicity and protective capacity against challenge with either strain. Mice and guinea pigs immunized with the bivalent S. flexneri 2a/S. sonnei Invaplex vaccine produced serum IgA and IgG antibodies to S. flexneri LPS, S. sonnei LPS, the homologous Invaplex and the water extract antigens (invasins) as determined by ELISA. The immune responses in animals immunized with the bivalent vaccine were similar to responses in animals immunized with the monovalent Invaplex vaccines. Mice and guinea pigs immunized with the bivalent vaccine were protected from a lethal lung challenge (mice, P<0.001) or severe keratoconjunctivitis (guinea pigs, P< or = 0.002) after challenge with either S. flexneri 2a or S. sonnei. Animals immunized with monovalent Invaplex vaccines were protected (P<0.001) against the homologous agent at levels comparable to the bivalent vaccine. After challenge, immunized animals demonstrated boosts in antibody titers to LPS, water extract antigens and Invaplex. These studies indicate that the subcellular Invaplex vaccine will be readily adaptable to a multivalent vaccine approach for shigellosis.
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Affiliation(s)
- Edwin V Oaks
- Walter Reed Army Institute of Research, Silver Spring, MD 20910-7510, USA.
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Walker RI. Considerations for development of whole cell bacterial vaccines to prevent diarrheal diseases in children in developing countries. Vaccine 2005; 23:3369-85. [PMID: 15837361 DOI: 10.1016/j.vaccine.2004.12.029] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 11/23/2004] [Accepted: 12/06/2004] [Indexed: 10/25/2022]
Abstract
Enteric pathogens constitute a major pediatric threat in the developing world through their impact on morbidity and mortality, physical and cognitive development and cause and effect relationship with malnutrition. Although many bacterial pathogens can cause diarrheal diseases, a group of less than 10 including Shigella spp., enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, and possibly, Campylobacter jejuni account for a significant percentage of these diseases in developing countries. Rotavirus is also a major cause of diarrheal diseases. Vaccines against these agents offer a potentially effective control measure against these diseases, but safe, practical, and effective vaccines for many of these agents have yet to be realized. Many vaccine development approaches are under investigation, but the one that is currently most advanced and that has been most widely applied to enteric pathogens is the use of orally administered live or killed whole pathogen preparations. If inactivated, these vaccines will probably be administered as multiple doses with approximately 10(10) to 10(11) total particles per dose, but they are relatively safe for oral administration. Further, they may not require a buffer for delivery and can be stored in liquid formulations. Fewer doses may be required for some live attenuated pathogen vaccines, but a buffer will most likely be required for oral delivery and the product must be stored in a dried formulation. Also, safety becomes more of a concern with live pathogens depending on the degree of attenuation, host immunocompetence, and the total number and kinds of attenuated pathogens which may be present in a combined agent vaccine. Both live and killed whole pathogen vaccines can be immunogenic and have the possibility to serve as vectors for other antigens. Although many organisms and serotypes are clinically important, by exploiting antigenic cross reactivity and using some pathogen components as vectors for cloned antigens of other pathogens, it could be possible to induce immunity against major enteric pathogens/serotypes with <10 whole pathogen components in a multi-agent vaccine. Safe and effective mucosal adjuvants may in the future be useful in whole pathogen vaccines, but they do not seem to be essential for immunization. Further, dietary supplements such as zinc, mixed routes of delivery and new regimens are under study which may in the future enhance further the effectiveness of the whole pathogen vaccines which now seem realizable in the near term. For this to happen, however, a coordinated and committed effort is necessary now to address the immunologic, regulatory, manufacturing, testing and implementation issues which will be involved in the realization of this important product to benefit children's health worldwide.
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Affiliation(s)
- Richard I Walker
- Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike (HFM-425), Rockville, MD 20851-1448, USA.
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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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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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