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Identification and evaluation of novel vaccine candidates against Shigella flexneri through reverse vaccinology approach. Appl Microbiol Biotechnol 2021; 105:1159-1173. [PMID: 33452891 PMCID: PMC7811352 DOI: 10.1007/s00253-020-11054-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/29/2020] [Accepted: 12/09/2020] [Indexed: 02/08/2023]
Abstract
Abstract Shigellosis is a significant type of diarrhea that causes 160,000 deaths annually in a global scale. The mortality occurs mainly in children less than 5 years of age. No licensed vaccine is available, and conventional efforts for developing an effective and safe vaccine against shigellosis have not been succeeded yet. The reverse vaccinology is a novel promising method that screens genome or proteome of an organism for finding new vaccine candidates. In this study, through reverse vaccinology approach, new vaccine candidates against Shigella flexneri were identified and experimentally evaluated. Proteomes of S. flexneri were obtained from UniProt, and then outer membrane and extracellular proteins were predicted and selected for the evaluation of transmembrane domains, protein conservation, host homology, antigenicity, and solubility. From 103 proteins, 7 high-scored proteins were introduced as novel vaccine candidates, and after B- and T-cell epitope prediction, the best protein was selected for experimental studies. Recombinant protein was expressed, purified, and injected to BALB/c mice. The adhesion inhibitory effect of sera was also studied. The immunized mice demonstrated full protection against the lethal dose challenge. The sera remarkably inhibited S. flexneri adhesion to Caco-2 epithelial cells. The results indicate that identified antigen can serve for vaccine development against shigellosis and support reverse vaccinology for discovering novel effective antigens. Key points • Seven Shigella new antigens were identified by reverse vaccinology (RV) approach. • The best antigen experimented demonstrated full protection against lethal dose. • In vivo results verified RV analyses and suggest FimG as a new potent vaccine candidate. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-020-11054-4.
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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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Zhang X, Li M, Zhang B, Chen K, He K. Development of a Sandwich ELISA for EHEC O157:H7 Intimin γ1. PLoS One 2016; 11:e0162274. [PMID: 27603508 PMCID: PMC5014315 DOI: 10.1371/journal.pone.0162274] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/20/2016] [Indexed: 12/27/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen of worldwide importance that causes foodborne infections in humans. Intimin gamma 1 (intimin γ1) is one of the most important outer membrane proteins required for EHEC’s intimate adhesion to epithelial cells. Here, we generated a polyclonal antibody (pAb) and a monoclonal antibody (mAb) against intimin γ1 to develop a double antibody sandwich ELISA (DAS-ELISA) with increased sensitivity and specificity for measuring EHEC O157:H7. To achieve this goal, a rabbit pAb was used as a capture antibody, and a mouse mAb was a detection antibody. No cross-reactivity was observed with the other genera of pathogenic bacteria tested with the DAS-ELISA, which included Salmonella enteritidis, Shigella flexneri type 2, Listeria monocytogenes, Streptococcus suis type 2, and other 18 serotype E. coli. Detection limits of the DAS-ELISA were 1 × 103 CFU/mL for EHEC O157:H7 cultures, 1 × 104 CFU/g before enrichment, and 1 × 102 CFU/g after enrichment of contaminated samples. Field samples (n = 498) were tested using a previously established duplex-PCR method and compared to our DAS-ELISA. The DAS-ELISA had a specificity of 94.4%, a sensitivity of 91.5% and accuracy of 94.0% compared with duplex-PCR. The DAS-ELISA developed here can be applied to EHEC O157:H7 quantification in food, animal, and environmental samples.
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Affiliation(s)
- Xuehan Zhang
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Engineering Research of Veterinary Bio-products of Agricultural Ministry, National Center for Engineering Research of Veterinary Bio-products, Nanjing 210014, China, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing 210014, China
- * E-mail: (XZ); (KH)
| | - Meng Li
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Engineering Research of Veterinary Bio-products of Agricultural Ministry, National Center for Engineering Research of Veterinary Bio-products, Nanjing 210014, China, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing 210014, China
| | - Bicheng Zhang
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Engineering Research of Veterinary Bio-products of Agricultural Ministry, National Center for Engineering Research of Veterinary Bio-products, Nanjing 210014, China, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing 210014, China
| | - Kangming Chen
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, United States of America
| | - Kongwang He
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Engineering Research of Veterinary Bio-products of Agricultural Ministry, National Center for Engineering Research of Veterinary Bio-products, Nanjing 210014, China, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing 210014, China
- * E-mail: (XZ); (KH)
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Flockhart AF, Tree JJ, Xu X, Karpiyevich M, McAteer SP, Rosenblum R, Shaw DJ, Low CJ, Best A, Gannon V, Laing C, Murphy KC, Leong JM, Schneiders T, La Ragione R, Gally DL. Identification of a novel prophage regulator in Escherichia coli controlling the expression of type III secretion. Mol Microbiol 2011; 83:208-23. [PMID: 22111928 PMCID: PMC3378721 DOI: 10.1111/j.1365-2958.2011.07927.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
This study has identified horizontally acquired genomic regions of enterohaemorrhagic Escherichia coli O157:H7 that regulate expression of the type III secretion (T3S) system encoded by the locus of enterocyte effacement (LEE). Deletion of O-island 51, a 14.93 kb cryptic prophage (CP-933C), resulted in a reduction in LEE expression and T3S. The deletion also had a reduced capacity to attach to epithelial cells and significantly reduced E. coli O157 excretion levels from sheep. Further characterization of O-island 51 identified a novel positive regulator of the LEE, encoded by ecs1581 in the E. coli O157:H7 strain Sakai genome and present but not annotated in the E. coli strain EDL933 sequence. Functionally important residues of ECs1581 were identified based on phenotypic variants present in sequenced E. coli strains and the regulator was termed RgdR based on a motif demonstrated to be important for stimulation of gene expression. While RgdR activated expression from the LEE1 promoter in the presence or absence of the LEE-encoded regulator (Ler), RgdR stimulation of T3S required ler and Ler autoregulation. RgdR also controlled the expression of other phenotypes, including motility, indicating that this new family of regulators may have a more global role in E. coli gene expression.
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Affiliation(s)
- Allen F Flockhart
- Immunity and Infection Division, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh EH25 9RG, UK
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Bovine colostrum contains immunoglobulin G antibodies against intimin, EspA, and EspB and inhibits hemolytic activity mediated by the type three secretion system of attaching and effacing Escherichia coli. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:1208-13. [PMID: 18562563 DOI: 10.1128/cvi.00027-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of gamma-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity.
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Blanco M, Blanco JE, Mora A, Dahbi G, Alonso MP, González EA, Bernárdez MI, Blanco J. Serotypes, virulence genes, and intimin types of Shiga toxin (verotoxin)-producing Escherichia coli isolates from cattle in Spain and identification of a new intimin variant gene (eae-xi). J Clin Microbiol 2004; 42:645-51. [PMID: 14766831 PMCID: PMC344521 DOI: 10.1128/jcm.42.2.645-651.2004] [Citation(s) in RCA: 232] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Accepted: 10/29/2003] [Indexed: 11/20/2022] Open
Abstract
A total of 514 Shiga toxin-producing Escherichia coli (STEC) isolates from diarrheic and healthy cattle in Spain were characterized in this study. PCR showed that 101 (20%) isolates carried stx(1) genes, 278 (54%) possessed stx(2) genes, and 135 (26%) possessed both stx(1) and stx(2). Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 326 (63%) and in 151 (29%) of the isolates, respectively. STEC isolates belonged to 66 O serogroups and 113 O:H serotypes (including 23 new serotypes). However, 67% were of one of these 15 serogroups (O2, O4, O8, O20, O22, O26, O77, O91, O105, O113, O116, O157, O171, O174, and OX177) and 52% of the isolates belonged to only 10 serotypes (O4:H4, O20:H19, O22:H8, O26:H11, O77:H41, O105:H18, O113:H21, O157:H7, O171:H2, and ONT:H19). Although the 514 STEC isolates belonged to 164 different seropathotypes (associations between serotypes and virulence genes), only 12 accounted for 43% of isolates. Seropathotype O157:H7 stx(2) eae-gamma1 ehxA (46 isolates) was the most common, followed by O157:H7 stx(1) stx(2) eae-gamma1 ehxA (34 isolates), O113:H21 stx(2) (25 isolates), O22:H8 stx(1) stx(2) ehxA (15 isolates), O26:H11 stx(1) eae-beta1 ehxA (14 isolates), and O77:H41 stx(2) ehxA (14 isolates). Forty-one (22 of serotype O26:H11) isolates had intimin beta1, 82 O157:H7 isolates possessed intimin gamma1, three O111:H- isolates had intimin type gamma2, one O49:H- strain showed intimin type delta, 13 (six of serotype O103:H2) isolates had intimin type epsilon and eight (four of serotype O156:H-) isolates had intimin zeta. We have identified a new variant of the eae intimin gene designated xi (xi) in two isolates of serotype O80:H-. The majority (85%) of bovine STEC isolates belonged to serotypes previously found for human STEC organisms and 54% to serotypes associated with STEC organisms isolated from patients with hemolytic uremic syndrome. Thus, this study confirms that cattle are a major reservoir of STEC strains pathogenic for humans.
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Affiliation(s)
- M Blanco
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain
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Blanco M, Blanco JE, Mora A, Rey J, Alonso JM, Hermoso M, Hermoso J, Alonso MP, Dahbi G, González EA, Bernárdez MI, Blanco J. Serotypes, virulence genes, and intimin types of Shiga toxin (verotoxin)-producing Escherichia coli isolates from healthy sheep in Spain. J Clin Microbiol 2003; 41:1351-6. [PMID: 12682113 PMCID: PMC153932 DOI: 10.1128/jcm.41.4.1351-1356.2003] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fecal swabs obtained from 1,300 healthy lambs in 93 flocks in Spain in 1997 were examined for Shiga toxin-producing Escherichia coli (STEC). STEC O157:H7 strains were isolated from 5 (0.4%) animals in 4 flocks, and non-O157 STEC strains were isolated from 462 (36%) lambs in 63 flocks. A total of 384 ovine STEC strains were characterized in this study. PCR showed that 213 (55%) strains carried the stx(1) gene, 10 (3%) possessed the stx(2) gene, and 161 (42%) carried both the stx(1) and the stx(2) genes. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 106 (28%) and 23 (6%) of the STEC strains, respectively. The STEC strains belonged to 35 O serogroups and 64 O:H serotypes (including 18 new serotypes). However, 72% were of 1 of the following 12 serotypes: O5:H-, O6:H10, O91:H-, O117:H-, O128:H-, O128:H2, O136:H20, O146:H8, O146:H21, O156:H-, O166:H28, and ONT:H21 (where NT is nontypeable). Although the 384 STEC strains belonged to 95 different seropathotypes (associations between serotypes and virulence genes), 49% of strains belonged to only 11. O91:H- stx(1) stx(2) (54 strains) was the most common seropathotype, followed by O128:H- stx(1) stx(2) (33 strains) and O6:H10 stx(1) (25 strains). Three strains of serotypes O26:H11, O156:H11, and OX177:H11 had intimin type beta1; 5 strains of serotype O157:H7 possessed intimin type gamma1; and 15 strains of serotypes O49:H-, O52:H12, O156:H- (12 strains), and O156:H25 had the new intimin, intimin type zeta. The majority (82%) of ovine STEC strains belonged to serotypes previously found to be associated with human STEC strains, and 51% belonged to serotypes associated with STEC strains isolated from patients with hemolytic-uremic syndrome. Thus, this study confirms that healthy sheep are a major reservoir of STEC strains pathogenic for humans.
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Affiliation(s)
- M Blanco
- Laboratorio de Referencia de E. coli, Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Campus de Lugo, 27002 Lugo, Spain
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