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Boyle AG. Streptococcus equi Subspecies equi. Vet Clin North Am Equine Pract 2023; 39:115-131. [PMID: 36737294 DOI: 10.1016/j.cveq.2022.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Strangles, caused by the bacteria Streptococcus equi subsp equi, is a highly contagious disease of equids classically characterized by a high fever and enlarged lymph nodes of the head. Diagnostic sampling depends on the stage of the disease. The goal of treating strangles is to control transmission and to eliminate infection while providing future host immunity. Daily temperature checking and isolation of febrile horses is the key to controlling outbreaks. Eradication of this disease will not be possible until S equi carriers are eliminated from the equine population.
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Affiliation(s)
- Ashley G Boyle
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, 382 West Street Road, Kennett Square, PA 19348, USA.
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2
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Streptococcus equi-derived extracellular vesicles as a vaccine candidate against Streptococcus equi infection. Vet Microbiol 2021; 259:109165. [PMID: 34225054 DOI: 10.1016/j.vetmic.2021.109165] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/22/2021] [Indexed: 02/08/2023]
Abstract
Streptococcus equi subspecies equi is a pathogenic bacterium that causes strangles, a highly contagious respiratory infection in horses and other equines. The limitations of current vaccines against S. equi infection warrants the development of an affordable, safe, and effective vaccine. Because gram-positive extracellular vesicles (EVs) transport various immunogenic antigens, they are attractive vaccine candidates. Here, we purified the EVs of S. equi ATCC 39506 and evaluated them as a vaccine candidate against S. equi infection in mice. As an initial step, comparative proteomic analysis was performed to characterize the functional features of the EVs. Reverse vaccinology and knowledge-based annotations were then used to screen potential vaccine candidates (PVCs) for S. equi ATCC 39506. Finally, 32 PVCs were found to be enriched in the EV fraction, suggesting the usefulness of this fraction as a vaccine. Importantly, a significantly higher survival rate after S. equi infection was detected in mice immunized with S. equi-derived EVs via the intraperitoneal route than in mice immunized with heat-killed bacteria. Of note, immunoprecipitation-mass spectrometry results validated various immunogenic antigens within the EV proteome. In conclusion, our results suggest that S. equi-derived EVs can serve as a vaccine candidate against S. equi infection.
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Optimized GAPDH-truncated immunogen of Streptococcus equi elicits an enhanced immune response and provides effective protection in a mouse model. Vet Microbiol 2020; 254:108953. [PMID: 33647714 DOI: 10.1016/j.vetmic.2020.108953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 12/08/2020] [Indexed: 11/20/2022]
Abstract
Strangles is an acute and frequently diagnosed infectious disease caused by Streptococcus equi subsp. equi. Infection with this pathogen can cause grave losses to the equine industry. The present work investigates glyceraldehyde-3-phosphate dehydrogenase (GAPDH), an important surface-localized virulence factor of S. equi, to determine whether it could be developed into an efficacious and suitable subunit vaccine against strangles. Two different recombinant fragments of S. equi GAPDH, namely, GAPDH-L and GAPDH-S, were constructed and expressed. Further, the antigenicity and immunogenicity of these two recombinant proteins were compared and evaluated in a mouse model. Our results revealed that immune responses were efficiently induced by the proteins in immunized mice. Remarkably, higher survival rates and significantly lower bacterial loads in the lung, liver, kidney, and spleen were observed in the GAPDH-S group compared with the GAPDH-L group after challenge with S. equi. High levels of specific antibodies, elevated antibody titers, and increased proportions of CD8 + T cells further indicated that GAPDH-S elicited better humoral and cellular immune responses than GAPDH-L. Furthermore, the induction of TCR, TLR-2, TLR-3, and TLR-4 significantly increased in the GAPDH-S group compared with those in the GAPDH-L and negative control groups. In summary, our results indicate that the optimized recombinant protein GAPDH-S is a promising candidate construct that may be further developed into a multivalent subunit vaccine for strangles.
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El-Hage CM, Bannai H, Wiethoelter AK, Firestone SM, Heislers CM, Allen JL, Waller AS, Gilkerson JR. Serological responses of Australian horses using a commercial duplex indirect ELISA following vaccination against strangles. Aust Vet J 2019; 97:220-224. [PMID: 31236928 DOI: 10.1111/avj.12825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/22/2019] [Accepted: 02/18/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the nature of serological responses in Australian horses using a commercial duplex indirect ELISA (iELISA) following vaccination against strangles. DESIGN A group (n = 19) of client-owned horses from five properties were recruited to receive a primary course of a Streptococcus equi subsp. equi (S. equi) extract vaccine. Serological responses were determined by duplex iELISA incorporating S. equi-specific fragments of two cell wall proteins, SEQ2190 and SeM (antigens (Ag) A and C, respectively). METHODS The horses were administered a primary strangles vaccination course. Blood was collected immediately prior to each of the three vaccinations at 2-week intervals and additionally at 28 and 56 days following the 3rd vaccination (V3). RESULTS Significant increases in mean antibody levels of horses following vaccination were limited only to AgC, which was significantly increased at T2/V3, 14 days following V2 (ratio of geometric means = 3.7; 95% confidence interval (CI): 1.6, 8.4; P = 0.003). There was no increase in mean antibody to Ag A (ratio of geometric means = 1.4; 95% CI: 0.6, 3.2; P = 0.39). Four horses (22%) exceeded the test cut-off for AgC following vaccination. CONCLUSION Vaccination of Australian horses is unlikely to interfere greatly with detection of strangles using the duplex iELISA. No responses would be anticipated to AgA following vaccination with Equivac© S/Equivac© 2in1 and only a minority are likely to respond to AgC. We conclude that the results of this study validate the usefulness of the duplex iELISA to assist control measures for strangles outbreaks in Australian horse populations.
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Affiliation(s)
- C M El-Hage
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - H Bannai
- Equine Research Institute, Japan Racing Association Tochigi, Japan
| | - A K Wiethoelter
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - S M Firestone
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - C M Heislers
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - J L Allen
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - A S Waller
- Animal Health Trust, Kennett, Newmarket, UK
| | - J R Gilkerson
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
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D'Gama JD, Ma Z, Zhang H, Liu X, Fan H, Morris ERA, Cohen ND, Cywes-Bentley C, Pier GB, Waldor MK. A Conserved Streptococcal Virulence Regulator Controls the Expression of a Distinct Class of M-Like Proteins. mBio 2019; 10:e02500-19. [PMID: 31641092 PMCID: PMC6805998 DOI: 10.1128/mbio.02500-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 12/16/2022] Open
Abstract
Streptococcus equi subspecies zooepidemicus (SEZ) are group C streptococci that are important pathogens of economically valuable animals such as horses and pigs. Here, we found that many SEZ isolates bind to a monoclonal antibody that recognizes poly-N-acetylglucosamine (PNAG), a polymer that is found as a surface capsule-like structure on diverse microbes. A fluorescence-activated cell sorting-based transposon insertion sequencing (Tn-seq) screen, coupled with whole-genome sequencing, was used to search for genes for PNAG biosynthesis. Surprisingly, mutations in a gene encoding an M-like protein, szM, and the adjacent transcription factor, designated sezV, rendered strains PNAG negative. SezV was required for szM expression and transcriptome analysis showed that SezV has a small regulon. SEZ strains with inactivating mutations in either sezV or szM were highly attenuated in a mouse model of infection. Comparative genomic analyses revealed that linked sezV and szM homologues are present in all SEZ, S. equi subspecies equi (SEE), and M18 group A streptococcal (GAS) genomes in the database, but not in other streptococci. The antibody to PNAG bound to a wide range of SEZ, SEE, and M18 GAS strains. Immunochemical studies suggest that the SzM protein may be decorated with a PNAG-like oligosaccharide although an intact oligosaccharide substituent could not be isolated. Collectively, our findings suggest that the szM and sezV loci define a subtype of virulent streptococci and that an antibody to PNAG may have therapeutic applications in animal and human diseases caused by streptococci bearing SzM-like proteins.IMPORTANCE M proteins are surface-anchored virulence factors in group A streptococci, human pathogens. Here, we identified an M-like protein, SzM, and its positive regulator, SezV, in Streptococcus equi subspecies zooepidemicus (SEZ), an important group of pathogens for domesticated animals, including horses and pigs. SzM and SezV homologues were found in the genomes of all SEZ and S. equi subspecies equi and M18 group A streptococcal strains analyzed but not in other streptococci. Mutant SEZ strains lacking either sezV or szM were highly attenuated in a mouse model of infection. Collectively, our findings suggest that SezV-related regulators and the linked SzM family of M-like proteins define a new subset of virulent streptococci.
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Affiliation(s)
- Jonathan D D'Gama
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Zhe Ma
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, Nanjing, Jiangsu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
| | - Hailong Zhang
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Xu Liu
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, Nanjing, Jiangsu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, China
| | - Ellen Ruth A Morris
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, College Station, Texas, USA
| | - Noah D Cohen
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, College Station, Texas, USA
| | - Colette Cywes-Bentley
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Gerald B Pier
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Matthew K Waldor
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
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Ma X, Wang C, Zhang B, Xia L, Su Y. Antibody kinetics and immune profile analysis of a Streptococcus equi DNA vaccine expressing the FljB and SeM fusion protein in murine and equine models. Res Vet Sci 2019; 125:82-88. [PMID: 31174167 DOI: 10.1016/j.rvsc.2019.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 05/19/2019] [Accepted: 05/21/2019] [Indexed: 10/26/2022]
Abstract
Strangles is a highly prevalent, extremely contagious, and occasionally lethal infectious disease affecting horses worldwide. Prophylactic antibiotics are ineffective in prevention of disease but are recommended for exposed horses at the first sign of fever and any horse obviously ill from strangles or with complications and there is an urgent need of a cost-effective, safe, efficacious vaccine. In the present study, we sought to develop effective vaccines by fusing the Streptococcus equi subspecies equi (S. equi) antigen SeM with the flagellin of Salmonella abortus equi FljB. We also explored the immunogenicity and efficacy of this candidate vaccine in mice and horses by intramuscular injection. Mice and horses immunized with FljB-SeM DNA vaccine showed high levels of specific antibody and increased production of IFN-γ and IL-4. This confirmed that both Th1 and Th2 type responses were induced. The mice survival rate was significantly higher after immunization with FljB-SeM than with SeM alone. The FljB-SeM DNA could strengthen both the Th1 and Th2 immune responses compared to SeM and could provide better protection against S. equi. This technique could help develop a candidate vaccine for S. equi infection.
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Affiliation(s)
- Xiaohui Ma
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Caidie Wang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Baojiang Zhang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Lining Xia
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Yan Su
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China.
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Laing G, Christley R, Stringer A, Aklilu N, Ashine T, Newton R, Radford A, Pinchbeck G. Respiratory disease and sero-epidemiology of respiratory pathogens in the working horses of Ethiopia. Equine Vet J 2018; 50:793-799. [PMID: 29574904 PMCID: PMC6175379 DOI: 10.1111/evj.12834] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 03/02/2018] [Indexed: 12/02/2022]
Abstract
BACKGROUND Pathogens are frequently implicated in equine respiratory disease. In Ethiopia, respiratory disease is a frequent cause for presentation at veterinary clinics and a priority concern for users of working horses. However, there is little existing literature on possible aetiologies. OBJECTIVES Determine prevalence of respiratory signs and exposure to major respiratory pathogens through a serological survey. STUDY DESIGN Cross-sectional. METHODS Systematically selected horses from 19 sites in central Ethiopia were examined clinically and sampled once (August-December 2013). A face-to-face interview collected data on horses' management and history. Serological testing targeted equine influenza virus (EIV), equine herpesviruses-1 (EHV-1) and -4 (EHV-4), equine rhinitis viruses A (ERAV) and B (ERBV), equine arteritis virus (EAV) and Streptococcus equi subspecies equi (S. equi). RESULTS Owners reported a recent history of coughing in 38% of horses and nasal discharge in 7%. No animals were observed coughing during examination but 6% had a nasal discharge. Antibodies towards S. equi, were most prevalent (8%, 33/350). Antibodies to EAV were confirmed in one animal (0.3%). Low antibody titres to EHV-1/4 and ERA/BV suggested prior exposure but antibodies to EIV were not detected. Multivariable, multilevel logistic regression analysis for risk factors associated with S. equi serostatus showed higher odds of seropositivity in younger animals and those working less frequently. MAIN LIMITATIONS A single serological sample cannot describe dynamic changes in antibodies. Sampling horses at the place of work may result in healthy-worker bias. CONCLUSIONS S. equi may be endemic in this population and contributing, in part, to the occurrence of respiratory disease. Low prevalence of antibodies to viruses, with the exception of EIV, indicates these pathogens are present, but unlikely a predominant cause of respiratory signs and noninfectious causes of disease should also be investigated. Working horses in this region would be vulnerable to incursion of equine influenza.
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Affiliation(s)
- G. Laing
- Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
| | - R. Christley
- Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
| | - A. Stringer
- Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
| | - N. Aklilu
- SPANA (Society for the Protection of Animals Abroad)Debre ZeitEthiopia
| | - T. Ashine
- SPANA (Society for the Protection of Animals Abroad)Debre ZeitEthiopia
| | - R. Newton
- Animal Health TrustNewmarketSuffolkUK
| | - A. Radford
- Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
| | - G. Pinchbeck
- Institute of Infection and Global HealthUniversity of LiverpoolLiverpoolUK
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8
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Characterization of SeseC_01411 as a surface protective antigen of Streptococcus equi ssp. zooepidemicus. Res Vet Sci 2018; 118:517-521. [PMID: 29758536 DOI: 10.1016/j.rvsc.2018.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 05/05/2018] [Accepted: 05/07/2018] [Indexed: 11/23/2022]
Abstract
Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) is a commensal bacterium related to opportunistic infections of many species, including humans, dogs, cats, and pigs. SeseC_01411 has been proven to be immunogenic. However, its protective efficacy remained to be evaluated. In the present study, the purified recombinant SeseC_01411 could elicit a strong humoral antibody response and protect against lethal challenge with virulent SEZ in mice. Our finding confirmed that SeseC_01411 distributes on the surface of SEZ. In addition, the hyperimmune sera against SeseC_01411 could efficiently kill the bacteria in the phagocytosis test. The present study identified the immunogenic protein, SeseC_01411, as a novel surface protective antigen of SEZ.
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Boyle AG, Timoney JF, Newton JR, Hines MT, Waller AS, Buchanan BR. Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles-Revised Consensus Statement. J Vet Intern Med 2018; 32:633-647. [PMID: 29424487 PMCID: PMC5867011 DOI: 10.1111/jvim.15043] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/14/2017] [Accepted: 12/14/2017] [Indexed: 11/28/2022] Open
Abstract
This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the “gold standard” for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.
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Affiliation(s)
- A G Boyle
- University of Pennsylvania, New Bolton Center, Kennett Square, PA
| | - J F Timoney
- University of Kentucky, Gluck Research Center, Lexington, KY
| | | | - M T Hines
- University of Tennessee, Knoxville, TN
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Steward KF, Robinson C, Maskell DJ, Nenci C, Waller AS. Investigation of the Fim1 putative pilus locus of Streptococcus equi subspecies equi. MICROBIOLOGY-SGM 2017; 163:1217-1228. [PMID: 28749324 DOI: 10.1099/mic.0.000506] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Gram-positive bacterium Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, among the most frequently diagnosed infectious diseases of horses worldwide. Genome analysis of S. equi strain 4047 (Se4047) identified a putative operon, Fim1, with similarity to the pilus loci of other Gram-positive bacteria. The Fim1 locus was present in all strains of S. equi and its close relative S. equi subspecies zooepidemicus (S. zooepidemicus) that have been studied to date. In this study we provide evidence that the putative structural pilus proteins, SEQ_0936 and CNE, are produced on the cell surface during in vitro growth and in vivo infection. Although the proteins encoded within the Fim1 locus are not essential for attachment or biofilm formation, over-transcription of SEQ_0936 and CNE enhanced attachment to equine tissue in vitro. Our data suggest that whilst the Fim1 locus does not produce a polymerized pilus structure, the products of the Fim1 locus may fulfil an adhesive function. The putative pilus-associated regulator, tetR, which contains a nonsense mutation in S. equi, was able to regulate transcription of the Fim1 locus following repair and over-transcription, confirming its predicted role in the operon.
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Affiliation(s)
- Karen Frances Steward
- Centre of Preventative Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK
| | - Carl Robinson
- Centre of Preventative Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Chiara Nenci
- Elanco Animal Health, c/o Novartis Animal Health, Inc., Schwarzwaldallee 215, 4058 Basel, Swizerland
| | - Andrew Stephen Waller
- Centre of Preventative Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK
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In Vivo-Expressed Proteins of Virulent Leptospira interrogans Serovar Autumnalis N2 Elicit Strong IgM Responses of Value in Conclusive Diagnosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 23:65-72. [PMID: 26607308 DOI: 10.1128/cvi.00509-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/11/2015] [Indexed: 11/20/2022]
Abstract
Leptospirosis is a serious zoonosis that is underdiagnosed because of limited access to laboratory facilities in Southeast Asia, Central and South America, and Oceania. Timely diagnosis of locally distributed serovars of high virulence is crucial for successful care and outbreak management. Using pooled patient sera, an expression gene library of a virulent Leptospira interrogans serovar Autumnalis strain N2 isolated in South India was screened. The identified genes were characterized, and the purified recombinant proteins were used as antigens in IgM enzyme-linked immunosorbent assay (ELISA) either singly or in combination. Sera (n = 118) from cases of acute leptospirosis along with sera (n = 58) from healthy subjects were tested for reactivity with the identified proteins in an ELISA designed to detect specific IgM responses. We have identified nine immunoreactive proteins, ArgC, RecA, GlpF, FliD, TrmD, RplS, RnhB, Lp28.6, and Lrr44.9, which were found to be highly conserved among pathogenic leptospires. Apparently, the proteins ArgC, RecA, GlpF, FliD, TrmD, and Lrr44.9 are expressed during natural infection of the host and undetectable in in vitro cultures. Among all the recombinant proteins used as antigens in IgM ELISA, ArgC had the highest sensitivity and specificity, 89.8% and 95.5%, respectively, for the conclusive diagnosis of leptospirosis. The use of ArgC and RecA in combination for IgM ELISA increased the sensitivity and specificity to 95.7% and 94.9%, respectively. ArgC and RecA thus elicited specific IgM responses and were therefore effective in laboratory confirmation of Leptospira infection.
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12
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Comparison of specificities of serum antibody responses of horses to clinical infections caused by Streptococcus equi or zooepidemicus. Vet Microbiol 2015; 180:253-9. [DOI: 10.1016/j.vetmic.2015.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/04/2015] [Accepted: 09/09/2015] [Indexed: 11/20/2022]
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13
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Robinson C, Heather Z, Slater J, Potts N, Steward KF, Maskell DJ, Fontaine MC, Lee JJ, Smith K, Waller AS. Vaccination with a live multi-gene deletion strain protects horses against virulent challenge with Streptococcus equi. Vaccine 2015; 33:1160-7. [PMID: 25597942 DOI: 10.1016/j.vaccine.2015.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 01/05/2015] [Accepted: 01/06/2015] [Indexed: 10/24/2022]
Abstract
Strangles, caused by Streptococcus equi subspecies equi (S. equi) is one of the most frequently diagnosed infectious diseases of horses and there remains a significant need to develop new preventative vaccines. We generated a live vaccine strain of S. equi containing deletions in six genes: sagA, hasA, aroB, pyrC, seM and recA, which was administered to nine Welsh mountain ponies via the intramuscular route. Four vaccinated ponies developed adverse reactions following the first vaccination from which the live vaccine strain was isolated. Two of these ponies were withdrawn from the study and seven ponies received a second vaccination, one of which then developed an adverse reaction. Nine control ponies injected with culture media alone developed no adverse reactions. Following challenge with a virulent strain of S. equi, none of the seven vaccinated ponies had developed clinical signs of strangles eleven days post-challenge, compared to six of nine control ponies over the same period (P=0.0114). A lymph node abscess was identified in one of the seven vaccinated ponies at post-mortem examination, whilst all nine control ponies had at least one lymph node abscess (P=0.0009). Three of the six vaccinated ponies that were protected from strangles had not developed an adverse reaction following vaccination, suggesting that a better understanding of the pro-inflammatory responses to S. equi could lead to the development of a live attenuated vaccine against strangles that is safe for administration via intramuscular injection.
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Affiliation(s)
- Carl Robinson
- Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, United Kingdom
| | - Zoe Heather
- Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, United Kingdom
| | - Josh Slater
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts AL9 7TA, United Kingdom
| | - Nicola Potts
- Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, United Kingdom
| | - Karen F Steward
- Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, United Kingdom
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, United Kingdom
| | - Michael C Fontaine
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Jeong-Jin Lee
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Ken Smith
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts AL9 7TA, United Kingdom
| | - Andrew S Waller
- Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, United Kingdom.
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14
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Waller AS. New perspectives for the diagnosis, control, treatment, and prevention of strangles in horses. Vet Clin North Am Equine Pract 2014; 30:591-607. [PMID: 25300634 DOI: 10.1016/j.cveq.2014.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Strangles, characterized by abscessation of the lymph nodes of the head and neck, is the most frequently diagnosed infectious disease of horses worldwide. The persistence of the causative agent, Streptococcus equi, in a proportion of convalescent horses plays a critical role in the recurrence and spread of disease. Recent research has led to the development of effective diagnostic tests that assist the eradication of S equi from local horse populations. This article describes how these advances have been made and provides advice to assist the resolution and prevention of outbreaks. New perspectives on preventative vaccines and therapeutic interventions are discussed.
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Affiliation(s)
- Andrew S Waller
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK.
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15
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Gallotta M, Gancitano G, Pietrocola G, Mora M, Pezzicoli A, Tuscano G, Chiarot E, Nardi-Dei V, Taddei AR, Rindi S, Speziale P, Soriani M, Grandi G, Margarit I, Bensi G. SpyAD, a moonlighting protein of group A Streptococcus contributing to bacterial division and host cell adhesion. Infect Immun 2014; 82:2890-901. [PMID: 24778116 PMCID: PMC4097626 DOI: 10.1128/iai.00064-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/15/2014] [Indexed: 11/20/2022] Open
Abstract
Group A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of the spy0269 gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interact in vitro with the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cells in vitro and that Lactococcus lactis expressing Spy0269 on its cell surface could adhere to mammalian cells in vitro and to mice nasal mucosa in vivo. On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD (Streptococcus pyogenes Adhesion and Division protein).
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Affiliation(s)
| | | | - Giampiero Pietrocola
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy
| | | | | | | | | | | | - Anna Rita Taddei
- Centre for High Instruments, Electron Microscopy Section, University of Tuscia, Viterbo, Italy
| | - Simonetta Rindi
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy
| | - Pietro Speziale
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Pavia, Italy
| | | | - Guido Grandi
- Novartis Vaccines and Diagnostics Srl, Siena, Italy
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16
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Velineni S, Desoutter D, Perchec AM, Timoney JF. Characterization of a mucoid clone of Streptococcus zooepidemicus from an epizootic of equine respiratory disease in New Caledonia. Vet J 2014; 200:82-7. [PMID: 24618399 DOI: 10.1016/j.tvjl.2014.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 01/21/2014] [Accepted: 01/23/2014] [Indexed: 11/18/2022]
Abstract
Streptococcus equi subspecies zooepidemicus (Sz) is a tonsillar and mucosal commensal of healthy horses with the potential to cause opportunistic infections of the distal respiratory tract stressed by virus infection, transportation, training or high temperature. The invasive clone varies from horse to horse with little evidence of lateral transmission in the group. Tonsillar isolates are non-mucoid although primary isolates from opportunist lower respiratory tract infections may initially be mucoid. In this study, a novel stably mucoid Sz (SzNC) from a clonal epizootic of respiratory disease in horses in different parts of New Caledonia is described. SzNC (ST-307) was isolated in pure culture from transtracheal aspirates and as heavy growths from 80% of nasal swabs (n=31). Only 4% of swabs from unaffected horses (n=25) yielded colonies of Sz. A viral etiology was ruled out based on culture and early/late serum antibody screening. Evidence for clonality of SzNC included a mucoid colony phenotype, SzP and SzM sequences, and multilocus sequence typing. SzNC, with the exception of isolates at the end of the outbreak, was hyaluronidase positive. Its SzP protein was composed of an N2 terminal, and HV4 variable region motifs and 18 carboxy terminal PEPK repeats. Biotin labeling of surface proteins revealed DnaK and alanyl-tRNA synthetase (AlaS) on the surface of clonal isolates, but not on non-clonal non-mucoid Sz from horses in the epizootic or unrelated US isolates. Reactivity of these proteins and SzP with convalescent serum indicated expression during infection.
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Affiliation(s)
- Sridhar Velineni
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
| | - Denise Desoutter
- Laboratoire Territorial de Diagnostic Vétérinaire, BP42 Paita, New Caledonia
| | - Anne-Marie Perchec
- Laboratoire Territorial de Diagnostic Vétérinaire, BP42 Paita, New Caledonia
| | - John F Timoney
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
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17
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Identification of novel immunoreactive proteins of Streptococcus zooepidemicus with potential as vaccine components. Vaccine 2013; 31:4129-35. [DOI: 10.1016/j.vaccine.2013.06.100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/17/2013] [Accepted: 06/25/2013] [Indexed: 11/21/2022]
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18
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Fu Q, Wei Z, Chen Y, Xiao P, Lu Z, Liu X. Identification of a surface protective antigen, CSP of Streptococcus equi ssp. zooepidemicus. Vaccine 2013; 31:1400-5. [PMID: 23306366 DOI: 10.1016/j.vaccine.2012.12.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 12/24/2012] [Accepted: 12/28/2012] [Indexed: 11/16/2022]
Abstract
Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) is an important pathogen associated with opportunistic infections of a wide range of species, including horses, pigs and humans. The absence of suitable vaccine confounds the control of SEZ infection. Cell surface protein (CSP) has been identified as an immunogenic protein in the previous study but its protective efficacy is not clear. In the present study, the purified recombinant CSP could elicit a significant humoral antibody response and could confer significant protection against challenge with lethal dose of SEZ in mice model. CSP could adhere to the HEp-2 cells confirmed by flow cytometry and inhibit adherence of SEZ to HEp-2 cells in an adherence inhibition assay. In addition, real-time PCR demonstrated that CSP was induced in vivo following infection of mice with SEZ. Our findings suggest that CSP may play a potential role in the pathogenesis of SEZ and could be a target for the development of a novel subunit vaccine against SEZ infection.
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Affiliation(s)
- Qiang Fu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, North Third Road, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, PR China
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19
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Rodrigues MA, Figueiredo L, Padrela L, Cadete A, Tiago J, Matos HA, Azevedo EGD, Florindo HF, Gonçalves LM, Almeida AJ. Development of a novel mucosal vaccine against strangles by supercritical enhanced atomization spray-drying of Streptococcus equi extracts and evaluation in a mouse model. Eur J Pharm Biopharm 2012; 82:392-400. [DOI: 10.1016/j.ejpb.2012.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/04/2012] [Accepted: 07/09/2012] [Indexed: 01/19/2023]
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20
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Figueiredo L, Cadete A, Gonçalves LMD, Corvo ML, Almeida AJ. Intranasal immunisation of mice against Streptococcus equi using positively charged nanoparticulate carrier systems. Vaccine 2012; 30:6551-8. [PMID: 22947139 DOI: 10.1016/j.vaccine.2012.08.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 07/23/2012] [Accepted: 08/20/2012] [Indexed: 01/25/2023]
Abstract
In order to potentiate a strong immune response after mucosal vaccination with a low immunogenic S. equi enzymatic extract, two positively charged particulate delivery systems (liposomes and nanoparticles) were created. Positively surface charged particles were expected to efficiently bind to negatively charged cell membranes and facilitate antigen uptake. Phosphatidylcholine-cholesterol-stearylamine liposomes encapsulating S. equi antigens were prepared and dimensionated to 0.22±0.01μm with a polydispersity index <0.242, zeta potential of +12±4mV and an encapsulation efficiency of 13±3% (w/w). Chitosan nanoparticles were prepared by ionotropic gelation with sodium tripolyphosphate, presenting a particle size of 0.17±0.01μm with polydispersity index <0.362, zeta potential of +23±8mV and an encapsulation efficiency of 53±6% (w/w). Both encapsulation methods were recognised as innocuous once antigens structure remained intact after incorporation as assessed by SDS-PAGE. Intranasal immunisation of mice with both formulations successfully elicited mucosal, humoral and cellular immune responses. Mucosal stimulation was confirmed by increased sIgA levels in the lungs, being the chitosan nanoparticles more successful in this achievement probably due to their different mucoadhesive properties. Both formulations share the ability to induce Th1-mediated immune responses characterised by IFN-γ production and high IgG2a antibody titers as well as a Th2 immune response characterised mainly by IL-4 production and IgG1 antibodies.
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Affiliation(s)
- L Figueiredo
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculdade de Farmácia da Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal
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21
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Ijaz M, Velineni S, Timoney JF. Selective pressure for allelic diversity in SeM of Streptococcus equi does not affect immunoreactive proteins SzPSe or Se18.9. INFECTION GENETICS AND EVOLUTION 2011; 11:1159-63. [PMID: 21256981 DOI: 10.1016/j.meegid.2011.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/22/2010] [Accepted: 01/16/2011] [Indexed: 01/25/2023]
Abstract
Streptococcus equi, a clone or biovar of an ancestral Streptococcus zooepidemicus of Lancefield group C causes equine strangles, a highly contagious tonsillitis and lymphadenitis of the head and neck. At least 74 alleles based on N-terminal amino acid sequence of the anti-phagocytic SeM have been observed among isolates of S. equi from N. America, Europe and Japan. A d(N)/d(S) ratio of 5.93 for the 5' region of sem is indicative of positive selective pressure. The aim of this study was to determine whether variations in SeM were accompanied by variations in the surface exposed SzPSe and secreted Se18.9, both of which bind to equine tonsillar epithelium and, along with SeM, elicit strong nasopharyngeal IgA responses during convalescence. Sequences of genes for these proteins from 25 S. equi expressing 19 different SeM alleles isolated over 40 years in different countries were compared. No variation was observed in szpse, except for an Australian isolate with a deletion of a single repeat in the 3' end of the gene. Interestingly, only two SNP loci were detected in se18.9 compared to 93 and 55 in sem and szpse, respectively. The high frequency of nucleotide substitutions in szpse may be related to its mosaic structure since this gene in S. zooepidemicus exists in a variety of combinations of sequence segments and has a central hypervariable region that includes exogenous DNA sequence based on an atypical G-C percentage. In summary, the results of this study document very different responses of streptococcal genes for 3 immunoreactive proteins to selection pressure of the nasopharyngeal mucosal immune response.
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Affiliation(s)
- Muhammad Ijaz
- Maxwell H Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546-0099, United States
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22
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Shao Z, Pan X, Li X, Liu W, Han M, Wang C, Wang J, Zheng F, Cao M, Tang J. HtpS, a novel immunogenic cell surface-exposed protein of Streptococcus suis, confers protection in mice. FEMS Microbiol Lett 2010; 314:174-82. [DOI: 10.1111/j.1574-6968.2010.02162.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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23
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Hobo S, Niwa H, Anzai T, Jones JH. Changes in Serum Antibody Levels after Vaccination for Strangles and after Intranasal Challenge with Streptococcus equi subsp. equi in Horses. J Equine Sci 2010; 21:33-7. [PMID: 24833976 PMCID: PMC4013967 DOI: 10.1294/jes.21.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2010] [Indexed: 11/05/2022] Open
Abstract
In this study, to evaluate the influence of strangles vaccination on serological test
results, we investigated the changes in strangles serum antibody levels in horses after
vaccination and subsequent intranasal challenge with S. equi. The horses were vaccinated
for strangles with either a component vaccine (Group C) or a live vaccine (Group L). We
measured changes in strangles serum antibody levels weekly for 20 weeks after vaccinating
horses twice for strangles over a 3-week interval, and for 7 weeks after intranasal
challenge with S. equi in the same horses. Serum antibody responses to the
proline-glutamic acid-proline-lysine (PEPK) antigen with five repetitions (PEPK-5R) were
higher at all times (up to 2.4-fold) following vaccination in Group C than in Group L, and
the value peaked at 2.9-fold above the initial value after the second vaccination in Group
C horses. However, the value was lower than that in horses infected with S. equi, and it
gradually decreased, reaching the initial (week 0) value by the 15th week. Serum antibody
responses to PEPK-5R after challenge with S. equi increased in both groups of horses, but
the value tended to be lower than that reported for unvaccinated horses. In addition, the
average value in Group C was 2.6-fold higher than that of Group L. These results suggest
the serum antibody responses of horses infected with S. equi varies according to the type
of vaccine with which they have been vaccinated. Although the serological diagnostic test
for strangles in which PEPK-5R is used as an antigen is effective for the investigation of
serum antibodies to strangles in vaccinated horses, the present data suggest it is
necessary to consider the vaccination history when interpreting the results.
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Affiliation(s)
- Seiji Hobo
- Epizootic Research Center, Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Hidekazu Niwa
- Epizootic Research Center, Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Toru Anzai
- Epizootic Research Center, Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - James H Jones
- Department of Surgical and Radiological Science, Giannini Equine Athletic Performance Laboratory, School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A
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24
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Protecting against Streptococcus zooepidemicus opportunism: The challenge of vaccine design. Vet J 2010; 184:128-9. [DOI: 10.1016/j.tvjl.2009.06.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 06/19/2009] [Indexed: 11/17/2022]
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25
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Knowles EJ, Mair TS, Butcher N, Waller AS, Wood JLN. Use of a novel serological test for exposure to Streptococcus equi subspecies equi in hospitalised horses. Vet Rec 2010; 166:294-7. [PMID: 20208076 DOI: 10.1136/vr.166.10.294] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Thirty horses with no external signs of strangles were tested for exposure to Streptococcus equi subspecies equi (S equi) using a new, commercially available serological test. The horses were also tested for persistent carriage of S equi by endoscopy of the guttural pouches and PCR analysis of lavage samples. The owners were questioned about the recent medical history of the horses. Serology suggested that four horses had been recently exposed to S equi. None of the horses had a known history of strangles but three of the four seropositive horses had recently shown non-specific signs of respiratory disease. One asymptomatic horse was positive for S equi by PCR, but none had both guttural pouch abnormalities and a positive PCR result. Ten additional horses known to have strangles were all seropositive by the serological test.
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Affiliation(s)
- E J Knowles
- Bell Equine Veterinary Clinic, Butchers Lane, Mereworth, Kent ME18 5GS.
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26
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Guss B, Flock M, Frykberg L, Waller AS, Robinson C, Smith KC, Flock JI. Getting to grips with strangles: an effective multi-component recombinant vaccine for the protection of horses from Streptococcus equi infection. PLoS Pathog 2009; 5:e1000584. [PMID: 19763180 PMCID: PMC2736577 DOI: 10.1371/journal.ppat.1000584] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 08/24/2009] [Indexed: 11/18/2022] Open
Abstract
Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine could confer broad protection to horses throughout the world. Welsh mountain ponies (n = 7) vaccinated with a combination of seven recombinant S. equi proteins were significantly protected from experimental infection by S. equi, resembling the spontaneous disease. Vaccinated horses had significantly reduced incidence of lymph node swelling (p = 0.0013) lymph node abscessation (p = 0.00001), fewer days of pyrexia (p = 0.0001), reduced pathology scoring (p = 0.005) and lower bacterial recovery from lymph nodes (p = 0.004) when compared with non-vaccinated horses (n = 7). Six of 7 vaccinated horses were protected whereas all 7 non-vaccinated became infected. The protective antigens consisted of five surface localized proteins and two IgG endopeptidases. A second vaccination trial (n = 7+7), in which the IgG endopeptidases were omitted, demonstrated only partial protection against S. equi, highlighting an important role for these vaccine components in establishing a protective immune response. S. equi shares >80% sequence identity with Streptococcus pyogenes. Several of the components utilized here have counterparts in S. pyogenes, suggesting that our findings have broader implications for the prevention of infection with this important human pathogen. This is one of only a few demonstrations of protection from streptococcal infection conferred by a recombinant multi-component subunit vaccine in a natural host. Numerous research groups have vaccinated, using recombinant antigens, against streptococcal infections in mouse model systems and shown protection. We have here demonstrated efficient protective vaccination of the natural host, the horse, using recombinant antigens. Streptococcus equi subspecies equi (S. equi) is an equine host-adapted and highly contagious pathogen of global importance. Six out of seven Welsh mountain ponies vaccinated with a combination of seven recombinant S. equi proteins were protected from experimental infection as assessed by clinical examination, pyrexia, lymph node swelling, inflammation, bacterial recovery, and post mortem examination. The protective antigens consisted of five surface localized proteins and two endopeptidases that are specific for IgG; the latter were shown to be of major importance for efficacy. Several of the antigens used here have similarities in Streptococcus pyogenes, implying that our findings are of importance for development of a vaccine against this important human pathogen.
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Affiliation(s)
- Bengt Guss
- Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Margareta Flock
- Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden
| | - Lars Frykberg
- Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Andrew S. Waller
- Department of Bacteriology, Animal Health Trust, Lanwades Park, Kentford, Newmarket, United Kingdom
| | - Carl Robinson
- Department of Bacteriology, Animal Health Trust, Lanwades Park, Kentford, Newmarket, United Kingdom
| | - Ken C. Smith
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, United Kingdom
| | - Jan-Ingmar Flock
- Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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27
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Abstract
Streptococci are clinically important Gram-positive bacteria that are capable to cause a wide variety of diseases in humans and animals. Phylogenetic analyses based on 16S rRNA sequences of the streptococcal species reveal a clustering pattern, reflecting, with a few exceptions, their pathogenic potential and ecological preferences. Microbial adhesion to host tissues is the initial critical event in the pathogenesis of most infections. Streptococci use multiple adhesins to attach to the epithelium, and their expression is regulated in response to environmental and growth conditions. Bacterial adhesins recognize and bind cell surface molecules and extracellular matrix components through specific domains that for certain adhesin families have been well defined and found conserved across the streptococcal species. In this review, we present the different streptococcal adhesin families categorized on the basis of their adhesive properties and structural characteristics, and, when available, we focus the attention on conserved functional domains.
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Affiliation(s)
- Monica Moschioni
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena, Italy
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28
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Antibody and cytokine-associated immune responses to S. equi antigens entrapped in PLA nanospheres. Biomaterials 2009; 30:5161-9. [PMID: 19524290 DOI: 10.1016/j.biomaterials.2009.05.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 05/21/2009] [Indexed: 01/31/2023]
Abstract
Strangles is an infectious disease caused by Streptococcus equi subspecies equi that affects the upper respiratory tract of the Equidae. The control of this disease seems to be dependent on its earlier detection and prevention, but prolonged animal protection without development of strong and severe side effects has not yet been achieved. Convalescent horses exhibit a protective immune response, mainly against SeM (58 kDa), an antiphagocytic and opsonogenic S. equi M-like protein, known as the major protective antigen against strangles. Purified recombinant SeM and S. equi protein extract-entrapped poly(lactic acid) (PLA) nanospheres were developed and their adjuvant potential was studied via the intramuscular route. The effect including molecules with adjuvant properties such as spermine, oleic acid, alginate and glycol-chitosan was also evaluated. Spherical nanometric particles <500 nm containing the protein antigen were prepared by the solvent evaporation method and protein structure was not affected throughout preparation. The humoral immune response induced by nanospheres was markedly higher than that elicited by soluble antigens, isolated or co-admixed with CpG. The IgG and IgG subtypes, along with cytokine titres, indicated that nanospheres composed by glycolchitosan developed a more balanced Th1/Th2 response for both purified SeM and S. equi enzymatic extract proteins, although those induced by the pure antigen-entrapped particles were higher than the S. equi tested vaccines composed by total antigens entrapped in polymeric nanospheres.
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29
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Abstract
REASONS FOR PERFORMING STUDY Little is known about entry and subsequent multiplication of Streptococcus equi following exposure of a susceptible horse. This information would have value in design of intranasal vaccines and understanding of shedding and protective immune responses. OBJECTIVES To determine entry points and sites of subsequent replication and dispersion of S. equi at different times after intranasal infection or commingling exposure. METHODS Previously unexposed horses and ponies were subjected to euthanasia 1, 3, 20 or 48 h following intranasal inoculation with biotin labelled or unlabelled S. equi CF32. Some ponies were inoculated with suspensions of equal numbers of CF32 and its mutants lacking capsule, S. equi M-like protein or streptolysin S. Others were infected by commingling exposure and subjected to euthanasia after onset of fever. Tonsils and lymph nodes were cultured for S. equi and tissues sectioned for histopathological examination and fluorescent microscopy. RESULTS Tonsillar tissues of both the oro- and nasopharynx served as portals of entry. Entry was unexpectedly rapid but involved few bacteria. Small numbers of organisms were detected in tonsillar crypts, in adjacent subepithelial follicular tissue and draining lymph nodes 3 h after inoculation. By 48 h, clumps of S. equi were visible in the lamina propria. At onset of fever, tonsillar tissues and one or more mandibular and retropharyngeal lymph nodes were heavily infiltrated by neutrophils and long chains of extracellular S. equi. Mutant S. equi lacking virulence factors were not seen in draining lymph nodes. CONCLUSIONS Although very small numbers of S. equi entered the lingual and nasopharyngeal tonsils, carriage to regional lymph nodes occurred within hours of inoculation. This observation, together with visual evidence of intracellular and extracellular multiplication of S. equi in tonsillar lymphoid tissue and lymph nodes over the following days, indicates involvement of potent antiphagocytic activity and failure of innate immune defences. RELEVANCE Future research should logically address the tonsillar immune mechanisms involved including identification of effector cell(s) and antigens.
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Affiliation(s)
- J F Timoney
- Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546-0099, USA
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30
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Movahedi AR, Hampson DJ. New ways to identify novel bacterial antigens for vaccine development. Vet Microbiol 2008; 131:1-13. [PMID: 18372122 DOI: 10.1016/j.vetmic.2008.02.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 02/07/2008] [Accepted: 02/08/2008] [Indexed: 11/27/2022]
Abstract
This article provides an overview of developments in approaches to identify novel bacterial components for use in recombinant subunit vaccines. In particular it describes the processes involved in "reverse vaccinology", and some associated complementary technologies such as proteomics that can be used in the identification of new and potentially useful vaccine antigens. Results obtained from the application of these new methods are forming a basis for a new generation of vaccines for use in the control of bacterial infections of humans and animals.
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Affiliation(s)
- Abdolreza Reza Movahedi
- School of Veterinary and Biomedical Science, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia
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31
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Timoney JF, Yang J, Liu J, Merant C. IdeE reduces the bactericidal activity of equine neutrophils for Streptococcus equi. Vet Immunol Immunopathol 2007; 122:76-82. [PMID: 18077002 DOI: 10.1016/j.vetimm.2007.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/28/2007] [Accepted: 10/31/2007] [Indexed: 11/18/2022]
Abstract
Streptococcus equi (S. equi) causes equine strangles, a highly contagious and widespread purulent lymphadenitis of the head and neck. Highly resistant to phagocytosis, it produces long extracellular chains in affected lymph nodes. In a screen of clones reactive with convalescent serum from a gene library of S. equi CF32 we identified IdeE, an IgG-endopeptidase and homologue of the leucocyte receptor Mac-1 (CD11b). IdeE is expressed during S. equi infection eliciting both serum and mucosal antibody responses which persisted at significant levels in serum for over 200 days. Release from S. equi into culture medium was detected during the exponential phase of growth. The closely related Streptococcus zooepidemicus appeared to store the protein but not to release it. Antiphagocytic activity for equine neutrophils was dose-dependent and neutralized by IdeE-specific antiserum. Biotinylated IdeE bound weakly to about 77% of purified equine neutrophils and strongly to the remainder.
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Affiliation(s)
- John F Timoney
- Department of Veterinary Science, University of Kentucky, Lexington, KY 40546-0099, USA.
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