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Zeng Y, Shen M, Liu S, Zhou X. Characterization and resistance mechanism of phage-resistant strains of Salmonella enteritidis. Poult Sci 2024; 103:103756. [PMID: 38652948 PMCID: PMC11063523 DOI: 10.1016/j.psj.2024.103756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/25/2024] [Accepted: 04/06/2024] [Indexed: 04/25/2024] Open
Abstract
In the face of the increasingly severe problem of antibiotic resistance, phage therapy is regarded as a highly potential alternative. Compared with traditional antimicrobial agents, a key research area of phage therapy is the study of phage-resistant mutant bacteria. To effectively monitor and prevent this resistance, it is crucial to conduct in-depth exploration of the mechanism behind phage resistance. In this study, a strain of Salmonella enteritidis (sm140) and the corresponding phage (Psm140) were isolated from chicken liver and sewage, respectively. Using the double-layer plate method, successfully screened out phage-resistant mutant strains. Whole-genome resequencing of 3 resistant strains found that the wbaP gene of all 3 strains had mutations at a specific position (1,118), with the base changing from G to A. This mutation causes the gene-encoded glycine to be replaced by aspartic acid. Subsequent studies found that the frequency of this gene mutation is extremely high, reaching 84%, and all mutations occur at the same position. To further explore the relationship between the wbaP gene and phage resistance, knockout strains and complement strains of the wbaP gene were constructed. The experimental results confirmed the association between the wbaP gene and phage resistance. At the same time, biological characteristics and virulence were evaluated for wild strains, resistant strains, knockout strains, and complement strains. It was found that mutations or deletions of the wbaP gene lead to a decrease in bacterial environmental adaptability and virulence. Through systematic research on the mechanism and biological characteristics of phage resistance, this study provides important references and guidance for the development of new phage therapies, promoting progress in the field of antimicrobial treatment. At the same time, the emergence of phage resistance due to wbaP gene mutations is reported for the first time in salmonella, providing a new perspective and ideas for further studying phage resistance mechanisms.
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Affiliation(s)
- Yukun Zeng
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Mangmang Shen
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Shenglong Liu
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China
| | - Xin Zhou
- College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China.
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2
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Abstract
This review is focused on describing and analyzing means by which Salmonella enterica serotype strains have been genetically modified with the purpose of developing safe, efficacious vaccines to present Salmonella-induced disease in poultry and to prevent Salmonella colonization of poultry to reduce transmission through the food chain in and on eggs and poultry meat. Emphasis is on use of recently developed means to generate defined deletion mutations to eliminate genetic sequences conferring antimicrobial resistance or residual elements that might lead to genetic instability. Problems associated with prior means to develop vaccines are discussed with presentation of various means by which these problems have been lessened, if not eliminated. Practical considerations are also discussed in hope of facilitating means to move lab-proven successful vaccination procedures and vaccine candidates to the marketplace to benefit the poultry industry.
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Affiliation(s)
- Roy Curtiss
- College of Veterinary Medicine, University of Florida, Gainesville, Florida,
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3
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Ghasemi A, Wang S, Sahay B, Abbott JR, Curtiss R. Protective immunity enhanced Salmonella vaccine vectors delivering Helicobacter pylori antigens reduce H. pylori stomach colonization in mice. Front Immunol 2022; 13:1034683. [DOI: 10.3389/fimmu.2022.1034683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/31/2022] [Indexed: 11/21/2022] Open
Abstract
Helicobacter pylori is a major cause of gastric mucosal inflammation, peptic ulcers, and gastric cancer. Emerging antimicrobial-resistant H. pylori has hampered the effective eradication of frequent chronic infections. Moreover, a safe vaccine is highly demanded due to the absence of effective vaccines against H. pylori. In this study, we employed a new innovative Protective Immunity Enhanced Salmonella Vaccine (PIESV) vector strain to deliver and express multiple H. pylori antigen genes. Immunization of mice with our vaccine delivering the HpaA, Hp-NAP, UreA and UreB antigens, provided sterile protection against H. pylori SS1 infection in 7 out of 10 tested mice. In comparison to the control groups that had received PBS or a PIESV carrying an empty vector, immunized mice exhibited specific and significant cellular recall responses and antigen-specific serum IgG1, IgG2c, total IgG and gastric IgA antibody titers. In conclusion, an improved S. Typhimurium-based live vaccine delivering four antigens shows promise as a safe and effective vaccine against H. pylori infection.
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Troxell B, Mendoza M, Ali R, Koci M, Hassan H. Attenuated Salmonella enterica Serovar Typhimurium, Strain NC983, Is Immunogenic, and Protective against Virulent Typhimurium Challenges in Mice. Vaccines (Basel) 2020; 8:vaccines8040646. [PMID: 33153043 PMCID: PMC7711481 DOI: 10.3390/vaccines8040646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 01/31/2023] Open
Abstract
Non-typhoidal Salmonella (NTS) serovars are significant health burden worldwide. Although much effort has been devoted to developing typhoid-based vaccines for humans, currently there is no NTS vaccine available. Presented here is the efficacy of a live attenuated serovar Typhimurium strain (NC983). Oral delivery of strain NC983 was capable of fully protecting C57BL/6 and BALB/c mice against challenge with virulent Typhimurium. Strain NC983 was found to elicit an anti-Typhimurium IgG response following administration of vaccine and boosting doses. Furthermore, in competition experiments with virulent S. Typhimurium (ATCC 14028), NC983 was highly defective in colonization of the murine liver and spleen. Collectively, these results indicate that strain NC983 is a potential live attenuated vaccine strain that warrants further development.
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Affiliation(s)
- Bryan Troxell
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; (B.T.); (M.M.); (R.A.); (M.K.)
| | - Mary Mendoza
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; (B.T.); (M.M.); (R.A.); (M.K.)
| | - Rizwana Ali
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; (B.T.); (M.M.); (R.A.); (M.K.)
| | - Matthew Koci
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; (B.T.); (M.M.); (R.A.); (M.K.)
| | - Hosni Hassan
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA; (B.T.); (M.M.); (R.A.); (M.K.)
- Microbiology Graduate Program, North Carolina State University, Raleigh, NC 27695, USA
- Correspondence: ; Tel.: +919-515-7081; Fax: +919-515-2625
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5
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Liu Q, Shen X, Bian X, Kong Q. Effect of deletion of gene cluster involved in synthesis of Enterobacterial common antigen on virulence and immunogenicity of live attenuated Salmonella vaccine when delivering heterologous Streptococcus pneumoniae antigen PspA. BMC Microbiol 2020; 20:150. [PMID: 32513100 PMCID: PMC7278252 DOI: 10.1186/s12866-020-01837-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/01/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae family. Previous studies showed that the loss of ECA results in Salmonella attenuation, indicating its usefulness as a vaccine candidate for Salmonella infection, but no studies have shown whether the mutation resulting from the deletion of the ECA operon in conjunction with other mutations could be used as an antigen vehicle for heterologous protein antigen delivery. RESULTS In this study, we introduced a nonpolar, defined ECA operon deletion into wild-type S. Typhimurium χ3761 and an attenuated vaccine strain χ9241, obtaining two isogenic ECA operon mutants, namely, χ12357 and χ12358, respectively. A number of in vitro and in vivo properties of the mutants were analyzed. We found that the loss of ECA did not affect the growth, lipopolysaccharide (LPS) production and motility of S. Typhimurium wild type strain χ3761 and its attenuated vaccine strain χ9241 but significantly affected the virulence when administered orally to BALB/c mice. Furthermore, the effects of the ECA mutation on the immunogenicity of a recombinant S. Typhimurium vaccine strain χ9241 when delivering the pneumococcal antigen PspA were determined. The result showed that the total anti-PspA IgG level of χ12358 (pYA4088) was slightly lower than that of χ9241 (pYA4088), but the protection rate was not compromised. CONCLUSIONS ECA affects virulence and benefits the Th2 immunity of Salmonella Typhimurium, therefore, it is feasible to use a reversible ECA mutant mode to design future Salmonella vaccine strains for heterologous protective antigens.
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Affiliation(s)
- Qing Liu
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Engineering Research Center for Herbivores Resource Protection and Utilization, Chongqing, China
| | - Xuegang Shen
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Xiaoping Bian
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Qingke Kong
- College of Animal Science and Technology, Southwest University, Chongqing, China.
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6
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Li YA, Chen Y, Du YZ, Guo W, Chu D, Fan J, Wang X, Bellefleur M, Wang S, Shi H. Live-attenuated Salmonella enterica serotype Choleraesuis vaccine with regulated delayed fur mutation confer protection against Streptococcus suis in mice. BMC Vet Res 2020; 16:129. [PMID: 32381017 PMCID: PMC7203871 DOI: 10.1186/s12917-020-02340-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 04/22/2020] [Indexed: 12/17/2022] Open
Abstract
Background Recombinant Salmonella enterica serotype Choleraesuis (S. Choleraesuis) vaccine vector could be used to deliver heterologous antigens to prevent and control pig diseases. We have previously shown that a live-attenuated S. Choleraesuis vaccine candidate strain rSC0011 (ΔPcrp527::TT araC PBADcrp Δpmi-2426 ΔrelA199::araC PBADlacI TT ΔasdA33, Δ, deletion, TT, terminator) delivering SaoA, a conserved surface protein in most of S. suis serotypes, provided excellent protection against S. suis challenge, but occasionally lead to morbidity (enteritidis) in vaccinated mice (approximately 1 in every 10 mice). Thus, alternated attenuation method was sought to reduce the reactogenicity of strain rSC0011. Herein, we described another recombinant attenuated S. Choleraesuis vector, rSC0012 (ΔPfur88:: TT araC PBADfur Δpmi-2426 ΔrelA199:: araC PBADlacI TT ΔasdA33) with regulated delayed fur mutation to avoid inducing disease symptoms while exhibiting a high degree of immunogenicity. Results The strain rSC0012 strain with the ΔPfur88::TT araC PBADfur mutation induced less production of inflammatory cytokines than strain rSC0011 with the ΔPcrp527::TT araC PBADcrp mutation in mice. When delivering the same pS-SaoA plasmid, the intraperitoneal LD50 of rSC0012 was 18.2 times higher than that of rSC0011 in 3-week-old BALB/C mice. rSC0012 with either pS-SaoA or pYA3493 was cleared from spleen and liver tissues 7 days earlier than rSC0011 with same vectors after oral inoculation. The strain rSC0012 synthesizing SaoA induced high titers of anti-SaoA antibodies in both systemic (IgG in serum) and mucosal (IgA in vaginal washes) sites, as well as increased level of IL-4, the facilitator of Th2-type T cell immune response in mice. The recombinant vaccine rSC0012(pS-SaoA) conferred high percentage of protection against S. suis or S. Choleraesuis challenge in BALB/C mice. Conclusions The live-attenuated Salmonella enterica serotype Choleraesuis vaccine rSC0012(pS-SaoA) with regulated delayed fur mutation provides a foundation for the development of a safe and effective vaccine against S. Choleraesuis and S. suis.
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Affiliation(s)
- Yu-An Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Key Laboratory of Animal Infectious Diseases, Ministry of Agriculture, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Preventive Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yunyun Chen
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Key Laboratory of Animal Infectious Diseases, Ministry of Agriculture, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Preventive Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yuan Zhao Du
- Yebio Bioengineering Co., Ltd of Qingdao, Qingdao, 266114, China
| | - Weiwei Guo
- Yebio Bioengineering Co., Ltd of Qingdao, Qingdao, 266114, China
| | - Dianfeng Chu
- Yebio Bioengineering Co., Ltd of Qingdao, Qingdao, 266114, China
| | - Juan Fan
- Yangzhou Uni-Bio Pharmaceutical Co., Ltd, Yangzhou, 225000, Jiangsu, China
| | - Xiaobo Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Key Laboratory of Animal Infectious Diseases, Ministry of Agriculture, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Preventive Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Matthew Bellefleur
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611-0880, USA
| | - Shifeng Wang
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611-0880, USA
| | - Huoying Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China. .,Key Laboratory of Animal Infectious Diseases, Ministry of Agriculture, Yangzhou University, Yangzhou, China. .,Jiangsu Key Laboratory of Preventive Veterinary Medicine, Yangzhou University, Yangzhou, China.
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7
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Arora D, Sharma C, Jaglan S, Lichtfouse E. Live-Attenuated Bacterial Vectors for Delivery of Mucosal Vaccines, DNA Vaccines, and Cancer Immunotherapy. ENVIRONMENTAL CHEMISTRY FOR A SUSTAINABLE WORLD 2019. [PMCID: PMC7123696 DOI: 10.1007/978-3-030-01881-8_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vaccines save millions of lives each year from various life-threatening infectious diseases, and there are more than 20 vaccines currently licensed for human use worldwide. Moreover, in recent decades immunotherapy has become the mainstream therapy, which highlights the tremendous potential of immune response mediators, including vaccines for prevention and treatment of various forms of cancer. However, despite the tremendous advances in microbiology and immunology, there are several vaccine preventable diseases which still lack effective vaccines. Classically, weakened forms (attenuated) of pathogenic microbes were used as vaccines. Although the attenuated microbes induce effective immune response, a significant risk of reversion to pathogenic forms remains. While in the twenty-first century, with the advent of genetic engineering, microbes can be tailored with desired properties. In this review, I have focused on the use of genetically modified bacteria for the delivery of vaccine antigens. More specifically, the live-attenuated bacteria, derived from pathogenic bacteria, possess many features that make them highly suitable vectors for the delivery of vaccine antigens. Bacteria can theoretically express any heterologous gene or can deliver mammalian expression vectors harboring vaccine antigens (DNA vaccines). These properties of live-attenuated microbes are being harnessed to make vaccines against several infectious and noninfectious diseases. In this regard, I have described the desired features of live-attenuated bacterial vectors and the mechanisms of immune responses manifested by live-attenuated bacterial vectors. Interestingly anaerobic bacteria are naturally attracted to tumors, which make them suitable vehicles to deliver tumor-associated antigens thus I have discussed important studies investigating the role of bacterial vectors in immunotherapy. Finally, I have provided important discussion on novel approaches for improvement and tailoring of live-attenuated bacterial vectors for the generation of desired immune responses.
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Affiliation(s)
- Divya Arora
- Indian Institute of Integrative Medicine, CSIR, Jammu, India
| | - Chetan Sharma
- Guru Angad Dev Veterinary and Animal Science University, Ludhiana, Punjab India
| | - Sundeep Jaglan
- Indian Institute of Integrative Medicine, CSIR, Jammu, India
| | - Eric Lichtfouse
- Aix Marseille University, CNRS, IRD, INRA, Coll France, CEREGE, Aix en Provence, France
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Zhao X, Liang S, Dai Q, Jia R, Zhu D, Liu M, Wang M, Chen S, Yang Q, Wu Y, Zhang S, Zhang L, Liu Y, Yu Y, Cheng A. Regulated delayed attenuation enhances the immunogenicity and protection provided by recombinant Salmonellaenterica serovar Typhimurium vaccines expressing serovar Choleraesuis O-polysaccharides. Vaccine 2018; 36:5010-5019. [DOI: 10.1016/j.vaccine.2018.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/12/2018] [Accepted: 07/04/2018] [Indexed: 12/27/2022]
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9
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Fuche FJ, Jones JA, Ramachandran G, Higginson EE, Simon R, Tennant SM. Deletions in guaBA and htrA but not clpX or rfaL constitute a live-attenuated vaccine strain of Salmonella Newport to protect against serogroup C 2-C 3 Salmonella in mice. Hum Vaccin Immunother 2018; 15:1427-1435. [PMID: 29927725 PMCID: PMC6663134 DOI: 10.1080/21645515.2018.1491499] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Non-typhoidal Salmonella (NTS) are a leading cause of foodborne infections worldwide, and serogroups B, C1, C2-C3 and D are the most common serogroups associated with human disease. While live vaccine candidates that protect against S. Typhimurium (serogroup B) and S. Enteritidis (serogroup D) have been described by us and others, far less effort has been directed towards vaccines that target either serogroup C1 or C2-C3Salmonella. Here we describe a Salmonella Newport-based live-attenuated vaccine (serogroup C2-C3). Deletion of the genes clpX or rfaL, previously used in live vaccines to attenuate S. Typhimurium and/or S. Enteritidis, failed to attenuate S. Newport. However, we found that deletion of either guaBA or htrA raised the 50% lethal dose of S. Newport in an intraperitoneal infection model in BALB/c mice. Our live-attenuated vaccine candidate CVD 1966 (S. Newport ΔguaBA ΔhtrA) elicited strong antibody responses against COPS, flagellin and outer membrane proteins when administered intraperitoneally or orally. Following lethal challenge with the parental virulent strain of S. Newport, we observed vaccine efficacies of 53% for immunization via the intraperitoneal route and 47% for immunization via the oral route. Following intraperiteonal immunization, the vaccine also significantly reduced the bacterial burden of challenge organisms in the liver and spleen. Interestingly, reducing the LPS chain length by deleting rfaL did not induce a stronger immune response towards surface antigens, and failed to elicit any protection against lethal homologous challenge. In conclusion, we have developed a live-attenuated Salmonella serogroup C2-C3 vaccine that we are further evaluating.
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Affiliation(s)
- Fabien J Fuche
- a Center for Vaccine Development and Institute for Global Health, Department of Medicine , University of Maryland School of Medicine , Baltimore , MD , USA
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10
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Conversion of RpoS - Attenuated Salmonella enterica Serovar Typhi Vaccine Strains to RpoS + Improves Their Resistance to Host Defense Barriers. mSphere 2018; 3:mSphere00006-18. [PMID: 29507892 PMCID: PMC5830471 DOI: 10.1128/msphere.00006-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/30/2018] [Indexed: 12/13/2022] Open
Abstract
Recombinant attenuated Salmonella vaccines (RASVs) represent a unique prevention strategy to combating infectious disease because they utilize the ability of Salmonella to invade and colonize deep effector lymphoid tissues and deliver hetero- and homologous derived antigens at the lowest immunizing dose. Our recent clinical trial in human volunteers indicated that an RpoS+ derivative of Ty2 was better at inducing immune responses than its RpoS− counterpart. In this study, we demonstrate that a functional RpoS allele is beneficial for developing effective live attenuated vaccines against S. Typhi or in using S. Typhi as a recombinant attenuated vaccine vector to deliver other protective antigens. The vast majority of live attenuated typhoid vaccines are constructed from the Salmonella enterica serovar Typhi strain Ty2, which is devoid of a functioning alternative sigma factor, RpoS, due to the presence of a frameshift mutation. RpoS is a specialized sigma factor that plays an important role in the general stress response of a number of Gram-negative organisms, including Salmonella. Previous studies have demonstrated that this sigma factor is necessary for survival following exposure to acid, hydrogen peroxide, nutrient-limiting conditions, and starvation. In addition, studies with Salmonella enterica serovar Typhimurium and the mouse model of typhoid fever have shown that RpoS is important in colonization and survival within the infected murine host. We converted 4 clinically studied candidate typhoid vaccine strains derived from Ty2 [CVD908-htrA, Ty800, and χ9639(pYA3493)] and the licensed live typhoid vaccine Ty21a (also derived from Ty2) to RpoS+ and compared their abilities to withstand environmental stresses that may be encountered within the host to those of the RpoS− parent strains. The results of our study indicate that strains that contain a functional RpoS were better able to survive following stress and that they would be ideal for further development as safe, effective vaccines to prevent S. Typhi infections or as vectors in recombinant attenuated Salmonella vaccines (RASVs) designed to protect against other infectious disease agents in humans. The S. Typhi strains constructed and described here will be made freely available upon request, as will the suicide vector used to convert rpoS mutants to RpoS+. IMPORTANCE Recombinant attenuated Salmonella vaccines (RASVs) represent a unique prevention strategy to combating infectious disease because they utilize the ability of Salmonella to invade and colonize deep effector lymphoid tissues and deliver hetero- and homologous derived antigens at the lowest immunizing dose. Our recent clinical trial in human volunteers indicated that an RpoS+ derivative of Ty2 was better at inducing immune responses than its RpoS− counterpart. In this study, we demonstrate that a functional RpoS allele is beneficial for developing effective live attenuated vaccines against S. Typhi or in using S. Typhi as a recombinant attenuated vaccine vector to deliver other protective antigens.
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11
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Clark-Curtiss JE, Curtiss R. Salmonella Vaccines: Conduits for Protective Antigens. THE JOURNAL OF IMMUNOLOGY 2018; 200:39-48. [PMID: 29255088 DOI: 10.4049/jimmunol.1600608] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 11/06/2017] [Indexed: 11/19/2022]
Abstract
Vaccines afford a better and more cost-effective approach to combatting infectious diseases than continued reliance on antibiotics or antiviral or antiparasite drugs in the current era of increasing incidences of diseases caused by drug-resistant pathogens. Recombinant attenuated Salmonella vaccines (RASVs) have been significantly improved to exhibit the same or better attributes than wild-type parental strains to colonize internal lymphoid tissues and persist there to serve as factories to continuously synthesize and deliver rAgs. Encoded by codon-optimized pathogen genes, Ags are selected to induce protective immunity to infection by that pathogen. After immunization through a mucosal surface, the RASV attributes maximize their abilities to elicit mucosal and systemic Ab responses and cell-mediated immune responses. This article summarizes many of the numerous innovative technologies and discoveries that have resulted in RASV platforms that will enable development of safe efficacious RASVs to protect animals and humans against a diversity of infectious disease agents.
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Affiliation(s)
- Josephine E Clark-Curtiss
- Division of Infectious Diseases and Global Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL 32610.,Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611
| | - Roy Curtiss
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611; and .,Department of Comparative, Diagnostic and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611
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12
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Li P, Liu Q, Luo H, Liang K, Yi J, Luo Y, Hu Y, Han Y, Kong Q. O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections. Front Immunol 2017; 8:1647. [PMID: 29255460 PMCID: PMC5722840 DOI: 10.3389/fimmu.2017.01647] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/10/2017] [Indexed: 12/16/2022] Open
Abstract
Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S. Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S. Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion–insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S. Typhimurium vaccine S738 (Δcrp Δcya) to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD50) of wild-type S. Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S. Typhimurium, S. Enteritidis, and S. Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S. Typhimurium vaccines against NTS infections.
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Affiliation(s)
- Pei Li
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Qing Liu
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Hongyan Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Kang Liang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Jie Yi
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ying Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yunlong Hu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yue Han
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, United States.,Department of Infectious Diseases and Pathology, University of Florida, Gainesville, FL, United States
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13
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Zhao X, Dai Q, Jia R, Zhu D, Liu M, Wang M, Chen S, Sun K, Yang Q, Wu Y, Cheng A. Two Novel Salmonella Bivalent Vaccines Confer Dual Protection against Two Salmonella Serovars in Mice. Front Cell Infect Microbiol 2017; 7:391. [PMID: 28929089 PMCID: PMC5591321 DOI: 10.3389/fcimb.2017.00391] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 08/22/2017] [Indexed: 12/12/2022] Open
Abstract
Non-typhoidal Salmonella includes thousands of serovars that are leading causes of foodborne diarrheal illness worldwide. In this study, we constructed three bivalent vaccines for preventing both Salmonella Typhimurium and Salmonella Newport infections by using the aspartate semialdehyde dehydrogenase (Asd)-based balanced-lethal vector-host system. The constructed Asd+ plasmid pCZ11 carrying a subset of the Salmonella Newport O-antigen gene cluster including the wzx-wbaR-wbaL-wbaQ-wzy-wbaW-wbaZ genes was introduced into three Salmonella Typhimurium mutants: SLT19 (Δasd) with a smooth LPS phenotype, SLT20 (Δasd ΔrfbN) with a rough LPS phenotype, and SLT22 (Δasd ΔrfbN ΔpagL::T araC PBADrfbN) with a smooth LPS phenotype when grown with arabinose. Immunoblotting demonstrated that SLT19 harboring pCZ11 [termed SLT19 (pCZ11)] co-expressed the homologous and heterologous O-antigens; SLT20 (pCZ11) exclusively expressed the heterologous O-antigen; and when arabinose was available, SLT22 (pCZ11) expressed both types of O-antigens, while in the absence of arabinose, SLT22 (pCZ11) expressed only the heterologous O-antigen. Exclusive expression of the heterologous O-antigen in Salmonella Typhimurium decreased the swimming ability of the bacterium and its susceptibility to polymyxin B. Next, the crp gene was deleted from the three recombinant strains for attenuation purposes, generating the three bivalent vaccine strains SLT25 (pCZ11), SLT26 (pCZ11), and SLT27 (pCZ11), respectively. Groups of BALB/c mice (12 mice/group) were orally immunized with 109 CFU of each vaccine strain twice at an interval of 4 weeks. Compared with a mock immunization, immunization with all three vaccine strains induced significant serum IgG responses against both Salmonella Typhimurium and Salmonella Newport LPS. The bacterial loads in the mouse tissues were significantly lower in the three vaccine-strain-immunized groups than in the mock group after either Salmonella Typhimurium or Salmonella Newport lethal challenge. All of the mice in the three vaccine-immunized groups survived the lethal Salmonella Typhimurium challenge. In contrast, SLT26 (pCZ11) and SLT27 (pCZ11) conferred full protection against lethal Salmonella Newport challenge, but SLT25 (pCZ11) provided only 50% heterologous protection. Thus, we developed two novel Salmonella bivalent vaccines, SLT26 (pCZ11) and SLT27 (pCZ11), suggesting that the delivery of a heterologous O-antigen in attenuated Salmonella strains is a prospective approach for developing Salmonella vaccines with broad serovar coverage.
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Affiliation(s)
- Xinxin Zhao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Qinlong Dai
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Renyong Jia
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Dekang Zhu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Mafeng Liu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Mingshu Wang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Shun Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Kunfeng Sun
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Qiao Yang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Ying Wu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Anchun Cheng
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan ProvinceChengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
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14
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Huang C, Liu Q, Luo Y, Li P, Liu Q, Kong Q. Regulated delayed synthesis of lipopolysaccharide and enterobacterial common antigen of Salmonella Typhimurium enhances immunogenicity and cross-protective efficacy against heterologous Salmonella challenge. Vaccine 2017; 34:4285-92. [PMID: 27423383 DOI: 10.1016/j.vaccine.2016.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/03/2016] [Accepted: 07/06/2016] [Indexed: 10/21/2022]
Abstract
Lipopolysaccharide (LPS) O-antigen and enterobacterial common antigen (ECA) are two major polysaccharide structures on the surface of Salmonella enterica serovar Typhimurium. Previous studies have demonstrated that regulated truncation of LPS enhances the cross-reaction against conserved outer membrane proteins (OMPs) from enteric bacteria. We speculate that the regulation of both O-antigen and ECA may enhance the induction of immune responses against conserved OMPs from enteric bacteria. In this work we targeted rfbB and rffG genes which encode dTDP-glucose 4,6-dehydratases and share the same function in regulating O-antigen and ECA synthesis. We constructed a mutant, S496 (ΔrfbB6 ΔrffG7 ΔpagL73::TT araC PBADrfbB-3), in which rfbB gene expression was dependent on exogenously supplied arabinose during in vitro growth and achieved the simultaneous tight regulation of both LPS and ECA synthesis, as demonstrated by the LPS profile and Western blotting using antisera against LPS and ECA. When administered orally, S. Typhimurium S496 was completely attenuated for virulence but still retained the capacity to colonize and disseminate in mice. In addition, we found that oral immunization with S496 resulted in increased immune responses against OMPs from enteric bacteria and enhanced survival compared with immunization with S492 possessing ΔrfbB6 ΔrffG8 mutations when challenged with lethal doses of Salmonella Choleraesuis or Salmonella Enteritidis. These results indicate that S. Typhimurium arabinose-regulated rfbB strain S496 is a good vaccine candidate, conferring cross-protection against lethal challenge with heterologous Salmonella.
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Affiliation(s)
- Chun Huang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qing Liu
- Department of Bioengineering, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Yali Luo
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Pei Li
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qiong Liu
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
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15
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Zhao X, Dai Q, Zhu D, Liu M, Chen S, Sun K, Yang Q, Wu Y, Kong Q, Jia R. Recombinant attenuated Salmonella Typhimurium with heterologous expression of the Salmonella Choleraesuis O-polysaccharide: high immunogenicity and protection. Sci Rep 2017; 7:7127. [PMID: 28754982 PMCID: PMC5533773 DOI: 10.1038/s41598-017-07689-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/03/2017] [Indexed: 11/29/2022] Open
Abstract
Non-typhoidal Salmonella are associated with gastrointestinal disease worldwide and invasive disease in Africa. We constructed novel bivalent vaccines through the recombinant expression of heterologous O-antigens from Salmonella Choleraesuis in Salmonella Typhimurium. A recombinant Asd+ plasmid pCZ1 with the cloned Salmonella Choleraesuis O-antigen gene cluster was introduced into three constructed Salmonella Typhimurium Δasd mutants: SLT11 (ΔrfbP), SLT12 (ΔrmlB-rfbP) and SLT16 (ΔrfbP ∆pagL::TT araCPBADrfbP). Immunoblotting demonstrated that SLT11 (pCZ1) and SLT12 (pCZ1) efficiently expressed the heterologous O-antigen. In the presence of arabinose, SLT16 (pCZ1) expressed both the homologous and heterologous O-antigens, whereas in the absence of arabinose, SLT16 (pCZ1) mainly expressed the heterologous O-antigen. We deleted the crp/cya genes in SLT12 (pCZ1) and SLT16 (pCZ1) for attenuation purposes, generating the recombinant vaccine strains SLT17 (pCZ1) and SLT18 (pCZ1). Immunization with either SLT17 (pCZ1) or SLT18 (pCZ1) induced specific IgG against the heterologous O-antigen, which mediated significant killing of Salmonella Choleraesuis and provided full protection against a lethal homologous challenge in mice. Furthermore, SLT17 (pCZ1) or SLT18 (pCZ1) immunization resulted in 83% or 50% heterologous protection against Salmonella Choleraesuis challenge, respectively. Our study demonstrates that heterologous O-antigen expression is a promising strategy for the development of multivalent Salmonella vaccines.
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Affiliation(s)
- Xinxin Zhao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Qinlong Dai
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Dekang Zhu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Mafeng Liu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Shun Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Kunfeng Sun
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Qiao Yang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Ying Wu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China. .,Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287-5401, USA.
| | - Renyong Jia
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China. .,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Wenjiang, Chengdu, Sichuan, 611130, P.R. China. .,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China.
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16
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Li P, Liu Q, Huang C, Zhao X, Roland KL, Kong Q. Reversible synthesis of colanic acid and O-antigen polysaccharides in Salmonella Typhimurium enhances induction of cross-immune responses and provides protection against heterologous Salmonella challenge. Vaccine 2017; 35:2862-2869. [PMID: 28412074 DOI: 10.1016/j.vaccine.2017.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 03/14/2017] [Accepted: 04/03/2017] [Indexed: 12/26/2022]
Abstract
Colanic Acid (CA) and lipopolysaccharide (LPS) are two major mannose-containing extracellular polysaccharides of Salmonella. Their presence on the bacterial surface can mask conserved protective outer membrane proteins (OMPs) from the host immune system. The mannose moiety in these molecules is derived from GDP-mannose, which is synthesized in several steps. The first two steps require the action of phosphomannose isomerase, encoded by pmi (manA), followed by phosphomannomutase, encoded by manB. There are two copies of manB present in the Salmonella chromosome, one located in the cps gene cluster (cpsG) responsible for CA synthesis, and the other in the rfb gene cluster (rfbK) involved in LPS O-antigen synthesis. In this study, it was demonstrated that the products of cpsG and rfbK are isozymes. To evaluate the impact of these genes on O-antigen synthesis, virulence and immunogenicity, single mutations (Δpmi, ΔrfbK or ΔcpsG) and a double mutation (ΔrfbK ΔcpsG) were introduced into both wild-type Salmonella enterica and an attenuated Δcya Δcrp vaccine strain. The Δpmi, ΔrfbK and ΔcpsG ΔrfbK mutants were defective in LPS synthesis and attenuated for virulence. In orally inoculated mice, strain S122 (Δcrp Δcya ΔcpsG ΔrfbK) and its parent S738 (Δcrp Δcya) were both avirulent and colonized internal tissues. Strain S122 elicited higher levels of anti-S. Typhimurium OMP serum IgG than its parent strain. Mice immunized with S122 were completely protected against challenge with wild-type virulent S. Typhimurium and partially protected against challenge with either wild-type virulent S. Choleraesuis or S. Enteritidis. These data indicate that deletions in rfbK and cpsG are useful mutations for inclusion in future attenuated Salmonella vaccine strains to induce cross-protective immunity.
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Affiliation(s)
- Pei Li
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5401, USA
| | - Qing Liu
- Department of Bioengineering, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Chun Huang
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Kenneth L Roland
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5401, USA
| | - Qingke Kong
- Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, China; Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-5401, USA.
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17
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Jiao Y, Guo R, Tang P, Kang X, Yin J, Wu K, Geng S, Li Q, Sun J, Xu X, Zhou X, Gan J, Jiao X, Liu X, Pan Z. Signature-tagged mutagenesis screening revealed a novel smooth-to-rough transition determinant of Salmonella enterica serovar Enteritidis. BMC Microbiol 2017; 17:48. [PMID: 28253852 PMCID: PMC5335844 DOI: 10.1186/s12866-017-0951-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 02/08/2017] [Indexed: 11/25/2022] Open
Abstract
Background Salmonella enterica serovar Enteritidis (S. Enteritidis) has emerged as one of the most important food-borne pathogens for humans. Lipopolysaccharide (LPS), as a component of the outer membrane, is responsible for the virulence and smooth-to-rough transition in S. Enteritidis. In this study, we screened S. Enteritidis signature-tagged transposon mutant library using monoclonal antibody against somatic O9 antigen (O9 MAb) and O9 factor rabbit antiserum to identify novel genes that are involved in smooth-to-rough transition. Results A total of 480 mutants were screened and one mutant with transposon insertion in rfbG gene had smooth-to-rough transition phenotype. In order to verify the role of rfbG gene, an rfbG insertion or deletion mutant was constructed using λ-Red recombination system. Phenotypic and biological analysis revealed that rfbG insertion or deletion mutants were similar to the wild-type strain in growth rate and biochemical properties, but the swimming motility was reduced. SE Slide Agglutination test and ELISA test showed that rfbG mutants do not stimulate animals to produce agglutinating antibody. In addition, the half-lethal dose (LD50) of the rfbG deletion mutant strain was 106.6 -fold higher than that of the parent strain in a mouse model when injected intraperitoneally. Conclusions These data indicate that the rfbG gene is involved in smooth-to-rough transition, swimming motility and virulence of S. Enteritidis. Furthermore, somatic O-antigen antibody-based approach to screen signature-tagged transposon mutants is feasible to clarify LPS biosynthesis and to find suitable markers in DIVA-vaccine research.
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Affiliation(s)
- Yang Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Rongxian Guo
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Peipei Tang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xilong Kang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Junlei Yin
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Kaiyue Wu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Shizhong Geng
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Qiuchun Li
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Jun Sun
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.,Division of Gastroenterology and Hepatology Department of Medicine, University of Illinois at Chicago, 840 S Wood Street, Room 704 CSB, 60612, Chicago, IL, USA
| | - Xiulong Xu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xiaohui Zhou
- Pathobiology and Veterinary Science, College of Agriculture, Health and Natural Resources, University of Connecticut, 61 North Eagleville Road, Unit-3089, Mansfield, CT, USA
| | - Junji Gan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xiufan Liu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.
| | - Zhiming Pan
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.
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18
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aroA-Deficient Salmonella enterica Serovar Typhimurium Is More Than a Metabolically Attenuated Mutant. mBio 2016; 7:mBio.01220-16. [PMID: 27601574 PMCID: PMC5013297 DOI: 10.1128/mbio.01220-16] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant attenuated Salmonella enterica serovar Typhimurium strains are believed to act as powerful live vaccine carriers that are able to elicit protection against various pathogens. Auxotrophic mutations, such as a deletion of aroA, are commonly introduced into such bacteria for attenuation without incapacitating immunostimulation. In this study, we describe the surprising finding that deletion of aroA dramatically increased the virulence of attenuated Salmonella in mouse models. Mutant bacteria lacking aroA elicited increased levels of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α) after systemic application. A detailed genetic and phenotypic characterization in combination with transcriptomic and metabolic profiling demonstrated that ΔaroA mutants display pleiotropic alterations in cellular physiology and lipid and amino acid metabolism, as well as increased sensitivity to penicillin, complement, and phagocytic uptake. In concert with other immunomodulating mutations, deletion of aroA affected flagellin phase variation and gene expression of the virulence-associated genes arnT and ansB. Finally, ΔaroA strains displayed significantly improved tumor therapeutic activity. These results highlight the importance of a functional shikimate pathway to control homeostatic bacterial physiology. They further highlight the great potential of ΔaroA-attenuated Salmonella for the development of vaccines and cancer therapies with important implications for host-pathogen interactions and translational medicine. Recombinant attenuated bacterial vector systems based on genetically engineered Salmonella have been developed as highly potent vaccines. Due to the pathogenic properties of Salmonella, efficient attenuation is required for clinical applications. Since the hallmark study by Hoiseth and Stocker in 1981 (S. K. Hoiseth and B. A. D. Stocker, Nature 291:238–239, 1981, http://dx.doi.org/10.1038/291238a0), the auxotrophic ΔaroA mutation has been generally considered safe and universally used to attenuate bacterial strains. Here, we are presenting the remarkable finding that a deletion of aroA leads to pronounced alterations of gene expression, metabolism, and cellular physiology, which resulted in increased immunogenicity, virulence, and adjuvant potential of Salmonella. These results suggest that the enhanced immunogenicity of aroA-deficient Salmonella strains might be advantageous for optimizing bacterial vaccine carriers and immunotherapy. Accordingly, we demonstrate a superior performance of ΔaroA Salmonella in bacterium-mediated tumor therapy. In addition, the present study highlights the importance of a functional shikimate pathway to sustain bacterial physiology and metabolism.
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19
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Felgner S, Kocijancic D, Frahm M, Weiss S. Bacteria in Cancer Therapy: Renaissance of an Old Concept. Int J Microbiol 2016; 2016:8451728. [PMID: 27051423 PMCID: PMC4802035 DOI: 10.1155/2016/8451728] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 02/03/2016] [Accepted: 02/11/2016] [Indexed: 01/20/2023] Open
Abstract
The rising incidence of cancer cases worldwide generates an urgent need of novel treatment options. Applying bacteria may represent a valuable therapeutic variant that is intensively investigated nowadays. Interestingly, the idea to apply bacteria wittingly or unwittingly dates back to ancient times and was revived in the 19th century mainly by the pioneer William Coley. This review summarizes and compares the results of the past 150 years in bacteria mediated tumor therapy from preclinical to clinical studies. Lessons we have learned from the past provide a solid foundation on which to base future efforts. In this regard, several perspectives are discussed by which bacteria in addition to their intrinsic antitumor effect can be used as vector systems that shuttle therapeutic compounds into the tumor. Strategic solutions like these provide a sound and more apt exploitation of bacteria that may overcome limitations of conventional therapies.
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Affiliation(s)
- Sebastian Felgner
- Department of Molecular Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Dino Kocijancic
- Department of Molecular Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Michael Frahm
- Department of Molecular Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Siegfried Weiss
- Department of Molecular Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
- Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany
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Mitra A, Łaniewski P, Curtiss R, Roland KL. A Live Oral Fowl Typhoid Vaccine with Reversible O-Antigen Production. Avian Dis 2015; 59:52-6. [PMID: 26292534 DOI: 10.1637/10885-061014-reg] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Salmonella enterica serovar Gallinarum causes fowl typhoid, recognized worldwide as an economically important disease. The current vaccine, 9R, lacks a complete O antigen, which is a Salmonella virulence factor, and, in addition, has a number of other less well characterized chromosomal mutations. For optimal efficacy, 9R is administered by injection. In an effort to develop a vaccine suitable for oral administration, we constructed Salmonella Gallinarum strains with a reversible O-antigen phenotype. In this scenario, the vaccine strain produces full-length O antigen at the time it is administered to birds. After the vaccine has had time to colonize internal lymphoid tissues, the O-antigen is gradually lost, resulting in an attenuated strain. We found that strains carrying single mutations conferring this phenotype, Apmi and arabinose-regulated rfc, retained virulence. However, a mutant strain carrying both of these mutations was completely attenuated and immunogenic in chickens. This work demonstrates a novel approach for developing live Salmonella vaccines for poultry.
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Frahm M, Felgner S, Kocijancic D, Rohde M, Hensel M, Curtiss R, Erhardt M, Weiss S. Efficiency of conditionally attenuated Salmonella enterica serovar Typhimurium in bacterium-mediated tumor therapy. mBio 2015; 6:e00254-15. [PMID: 25873375 PMCID: PMC4453544 DOI: 10.1128/mbio.00254-15] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/23/2015] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED Increasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria like Salmonella enterica serovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenic S. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbB mutants) of Salmonella were investigated for efficiency in tumor therapy. Of such variants, the ΔrfaD and ΔrfaG deep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into the araBAD locus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium. IMPORTANCE Cancer has become the second most frequent cause of death in industrialized countries. This and the drawbacks of routine therapies generate an urgent need for novel treatment options. Applying appropriately modified S. Typhimurium for therapy represents the major challenge of bacterium-mediated tumor therapy. In the present study, we demonstrated that Salmonella bacteria conditionally modified in their LPS phenotype exhibit a safe tumor-targeting phenotype. Moreover, they could represent a suitable vehicle to shuttle therapeutic compounds directly into cancerous tissue without harming the host.
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Affiliation(s)
- Michael Frahm
- Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Sebastian Felgner
- Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Dino Kocijancic
- Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Roy Curtiss
- Biodesign Institute, Center for Infectious Diseases and Vaccinology, Tempe, Arizona, USA
| | - Marc Erhardt
- Junior Research Group Infection Biology of Salmonella, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Siegfried Weiss
- Department of Molecular Immunology, Helmholtz Center for Infection Research, Braunschweig, Germany
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Zhang X, Kong W, Wanda SY, Xin W, Alamuri P, Curtiss R. Generation of influenza virus from avian cells infected by Salmonella carrying the viral genome. PLoS One 2015; 10:e0119041. [PMID: 25742162 PMCID: PMC4351096 DOI: 10.1371/journal.pone.0119041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 01/09/2015] [Indexed: 12/14/2022] Open
Abstract
Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 10⁷ 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo.
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Affiliation(s)
- Xiangmin Zhang
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, Michigan, United States of America
- * E-mail:
| | - Wei Kong
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Soo-Young Wanda
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Wei Xin
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Praveen Alamuri
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Roy Curtiss
- The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Life Science, Arizona State University, Tempe, Arizona, United States of America
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Abstract
This chapter reviews papers mostly written since 2005 that report results using live attenuated bacterial vectors to deliver after administration through mucosal surfaces, protective antigens, and DNA vaccines, encoding protective antigens to induce immune responses and/or protective immunity to pathogens that colonize on or invade through mucosal surfaces. Papers that report use of such vaccine vector systems for parenteral vaccination or to deal with nonmucosal pathogens or do not address induction of mucosal antibody and/or cellular immune responses are not reviewed.
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Evaluation of protective efficacy of live attenuated Salmonella enterica serovar Gallinarum vaccine strains against fowl typhoid in chickens. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:1267-76. [PMID: 24990908 DOI: 10.1128/cvi.00310-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Salmonella enterica serovar Gallinarum is the etiological agent of fowl typhoid, which constitutes a considerable economic problem for poultry growers in developing countries. The vaccination of chickens seems to be the most effective strategy to control the disease in those areas. We constructed S. Gallinarum strains with a deletion of the global regulatory gene fur and evaluated their virulence and protective efficacy in Rhode Island Red chicks and Brown Leghorn layers. The fur deletion mutant was avirulent and, when delivered orally to chicks, elicited excellent protection against lethal S. Gallinarum challenge. It was not as effective when given orally to older birds, although it was highly immunogenic when delivered by intramuscular injection. We also examined the effect of a pmi mutant and a combination of fur deletions with mutations in the pmi and rfaH genes, which affect O-antigen synthesis, and ansB, whose product inhibits host T-cell responses. The S. Gallinarum Δpmi mutant was only partially attenuated, and the ΔansB mutant was fully virulent. The Δfur Δpmi and Δfur ΔansB double mutants were attenuated but not protective when delivered orally to the chicks. However, a Δpmi Δfur strain was highly immunogenic when administered intramuscularly. All together, our results show that the fur gene is essential for the virulence of S. Gallinarum, and the fur mutant is effective as a live recombinant vaccine against fowl typhoid.
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Nandre RM, Lee JH. Construction of a recombinant-attenuated Salmonella Enteritidis strain secreting Escherichia coli heat-labile enterotoxin B subunit protein and its immunogenicity and protection efficacy against salmonellosis in chickens. Vaccine 2014; 32:425-31. [PMID: 24176491 DOI: 10.1016/j.vaccine.2013.10.054] [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: 08/09/2013] [Revised: 10/10/2013] [Accepted: 10/16/2013] [Indexed: 12/23/2022]
Abstract
A live attenuated Salmonella Enteritidis (SE) strain secreting Escherichia coli heat-labile enterotoxin B subunit (LTB) protein was constructed as a new vaccine candidate. The comparative effect of this vaccine candidate was evaluated with a previously reported SE vaccine, JOL919. An asd+, p15A ori plasmid containing eltB-encoding LTB was introduced into a ΔlonΔcpxRΔasd SE strain, and designated as JOL1364. In a single immunization experiment, group A chickens were orally inoculated with phosphate-buffered saline as a control, group B chickens were orally immunized with JOL919, and group C chickens were orally immunized with JOL1364. The immunized groups B and C showed significantly higher systemic, mucosal and cellular immune responses as compared to those of the control group. In addition, the immunized group C showed significantly higher mucosal and cellular immune responses as compared to those of the immunized group B at the 1st week post-immunization. In the examination of protection efficacy, the immunized groups B and C showed lower gross lesion scores in the liver and spleen, and lower bacterial counts of SE challenge strain in the liver, spleen, and caeca as compared to those of the control group. The number of SE-positive birds was significantly lower in the immunized group C as compared to that of the control group at the 14th day post-challenge. In addition, the number of birds carrying the challenge strain in the caeca was significantly lower in the immunized group C than those in the immunized group B and control group at the 7th and 14th day post-challenge. These results indicate that immunization with the JOL1364 vaccine candidate can induce higher mucosal and cellular immune responses than those of the JOL919 for efficient protection against salmonellosis.
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Affiliation(s)
- Rahul M Nandre
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Jeonju 561-756, South Korea
| | - John Hwa Lee
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Jeonju 561-756, South Korea.
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Abstract
Streptococcus pneumoniae still causes severe morbidity and mortality worldwide, especially in young children and the elderly. Much effort has been dedicated to developing protein-based universal vaccines to conquer the current shortcomings of capsular vaccines and capsular conjugate vaccines, such as serotype replacement, limited coverage and high costs. A recombinant live vector vaccine delivering protective antigens is a promising way to achieve this goal. In this review, we discuss the researches using live recombinant vaccines, mainly live attenuated Salmonella and lactic acid bacteria, to deliver pneumococcal antigens. We also discuss both the limitations and the future of these vaccines.
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Pei Y, Parreira VR, Roland KL, Curtiss R, Prescott JF. Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2014; 78:23-30. [PMID: 24396177 PMCID: PMC3878005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 03/15/2013] [Indexed: 06/03/2023]
Abstract
Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors.
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Affiliation(s)
| | | | | | | | - John F. Prescott
- Address all correspondence to Dr. John F. Prescott; telephone: (519) 824-4120 ext. 54716; fax: (519) 824-5930; e-mail:
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Mitra A, Loh A, Gonzales A, Laniewski P, Willingham C, Curtiss Iii R, Roland KL. Safety and protective efficacy of live attenuated Salmonella Gallinarum mutants in Rhode Island Red chickens. Vaccine 2012; 31:1094-9. [PMID: 23261043 DOI: 10.1016/j.vaccine.2012.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 11/01/2012] [Accepted: 12/10/2012] [Indexed: 01/17/2023]
Abstract
Salmonella enterica serovar Gallinarum is the causative agent of fowl typhoid, an important systemic disease of poultry with economic consequences in developing nations. A live attenuated orally applied S. Gallinarum vaccine could provide a low cost method for controlling this disease. We constructed S. Gallinarum strains in which the expression of the crp, rfc and rfaH genes, important for virulence of Salmonella Typhimurium in mice, were under the control of an arabinose-regulated promoter. We evaluated the virulence of these strains compared to wild-type S. Gallinarum and to mutants carrying deletions in these genes. We found that rfc mutants were fully virulent, indicating that, unlike the S. Typhimurium mouse model, the rfc gene is dispensable in S. Gallinarum for virulence in birds. In the case of rfaH, the deletion mutant was attenuated and protective, while the strain with arabinose-regulated rfaH expression retained full virulence. The strain exhibiting arabinose-regulated crp expression was attenuated. Its virulence was not affected by the inclusion of 0.2% arabinose in the drinking water. Birds immunized with this strain were protected against a lethal S. Gallinarum challenge and against colonization with the human pathogen Salmonella Enteritidis. This work shows that an arabinose-regulated crp strain provides a basis for further development of a fowl typhoid vaccine.
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Affiliation(s)
- Arindam Mitra
- The Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, AZ 85287, United States
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New technologies in developing recombinant attenuated Salmonella vaccine vectors. Microb Pathog 2012; 58:17-28. [PMID: 23142647 DOI: 10.1016/j.micpath.2012.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 10/29/2012] [Accepted: 10/30/2012] [Indexed: 01/01/2023]
Abstract
Recombinant attenuated Salmonella vaccine (RASV) vectors producing recombinant gene-encoded protective antigens should have special traits. These features ensure that the vaccines survive stresses encountered in the gastrointestinal tract following oral vaccination to colonize lymphoid tissues without causing disease symptoms and to result in induction of long-lasting protective immune responses. We recently described ways to achieve these goals by using regulated delayed in vivo attenuation and regulated delayed in vivo antigen synthesis, enabling RASVs to efficiently colonize effector lymphoid tissues and to serve as factories to synthesize protective antigens that induce higher protective immune responses. We also developed some additional new strategies to increase vaccine safety and efficiency. Modification of lipid A can reduce the inflammatory responses without compromising the vaccine efficiency. Outer membrane vesicles (OMVs) from Salmonella-containing heterologous protective antigens can be used to increase vaccine efficiency. A dual-plasmid system, possessing Asd+ and DadB+ selection markers, each specifying a different protective antigen, can be used to develop multivalent live vaccines. These new technologies have been adopted to develop a novel, low-cost RASV synthesizing multiple protective pneumococcal protein antigens that could be safe for newborns/infants and induce protective immunity to diverse Streptococcus pneumoniae serotypes after oral immunization.
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Phosphate groups of lipid A are essential for Salmonella enterica serovar Typhimurium virulence and affect innate and adaptive immunity. Infect Immun 2012; 80:3215-24. [PMID: 22753374 DOI: 10.1128/iai.00123-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lipid A is a key component of the outer membrane of Gram-negative bacteria and stimulates proinflammatory responses via the Toll-like receptor 4 (TLR4)-MD2-CD14 pathway. Its endotoxic activity depends on the number and length of acyl chains and its phosphorylation state. In Salmonella enterica serovar Typhimurium, removal of the secondary laurate or myristate chain in lipid A results in bacterial attenuation and growth defects in vitro. However, the roles of the two lipid A phosphate groups in bacterial virulence and immunogenicity remain unknown. Here, we used an S. Typhimurium msbB pagL pagP lpxR mutant, carrying penta-acylated lipid A, as the parent strain to construct a series of mutants synthesizing 1-dephosphorylated, 4'-dephosphorylated, or nonphosphorylated penta-acylated lipid A. Dephosphorylated mutants exhibited increased sensitivity to deoxycholate and showed increased resistance to polymyxin B. Removal of both phosphate groups severely attenuated the mutants when administered orally to BALB/c mice, but the mutants colonized the lymphatic tissues and were sufficiently immunogenic to protect the host from challenge with wild-type S. Typhimurium. Mice receiving S. Typhimurium with 1-dephosphorylated or nonphosphorylated penta-acylated lipid A exhibited reduced levels of cytokines. Attenuated and dephosphorylated Salmonella vaccines were able to induce adaptive immunity against heterologous (PspA of Streptococcus pneumoniae) and homologous antigens (lipopolysaccharide [LPS] and outer membrane proteins [OMPs]).
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Palmitoylation state impacts induction of innate and acquired immunity by the Salmonella enterica serovar typhimurium msbB mutant. Infect Immun 2011; 79:5027-38. [PMID: 21930761 DOI: 10.1128/iai.05524-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Lipopolysaccharide (LPS), composed of lipid A, core, and O-antigen, is a major virulence factor of Salmonella enterica serovar Typhimurium, with lipid A being a major stimulator to induce the proinflammatory response via the Toll-like receptor 4 (TLR4)-MD2-CD14 pathway. While Salmonella msbB mutants lacking the myristate chain in lipid A were investigated widely as an anticancer vaccine, inclusion of the msbB mutation in a Salmonella vaccine to deliver heterologous antigens has not yet been investigated. We introduced the msbB mutation alone or in combination with mutations in other lipid A acyl chain modification genes encoding PagL, PagP, and LpxR into wild-type S. enterica serovar Typhimurium. The msbB mutation reduced virulence, while the pagL, pagP, and lpxR mutations did not affect virulence in the msbB mutant background when administered orally to BALB/c mice. Also, all mutants exhibited sensitivity to polymyxin B but did not display sensitivity to deoxycholate. LPS derived from msbB mutants induced less inflammatory responses in human Mono Mac 6 and murine macrophage RAW264.7 cells in vitro. However, an msbB mutant did not decrease the induction of inflammatory responses in mice compared to the levels induced by the wild-type strain, whereas an msbB pagP mutant induced less inflammatory responses in vivo. The mutations were moved to an attenuated Salmonella vaccine strain to evaluate their effects on immunogenicity. Lipid A modification caused by the msbB mutation alone and in combination with pagL, pagP, and lpxR mutations led to higher IgA production in the vaginal tract but still retained the same IgG titer level in serum to PspA, a test antigen from Streptococcus pneumoniae, and to outer membrane proteins (OMPs) from Salmonella.
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Effect of deletion of genes involved in lipopolysaccharide core and O-antigen synthesis on virulence and immunogenicity of Salmonella enterica serovar typhimurium. Infect Immun 2011; 79:4227-39. [PMID: 21768282 DOI: 10.1128/iai.05398-11] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Lipopolysaccharide (LPS) is a major virulence factor of Salmonella enterica serovar Typhimurium and is composed of lipid A, core oligosaccharide (C-OS), and O-antigen polysaccharide (O-PS). While the functions of the gene products involved in synthesis of core and O-antigen have been elucidated, the effect of removing O-antigen and core sugars on the virulence and immunogenicity of Salmonella enterica serovar Typhimurium has not been systematically studied. We introduced nonpolar, defined deletion mutations in waaG (rfaG), waaI (rfaI), rfaH, waaJ (rfaJ), wbaP (rfbP), waaL (rfaL), or wzy (rfc) into wild-type S. Typhimurium. The LPS structure was confirmed, and a number of in vitro and in vivo properties of each mutant were analyzed. All mutants were significantly attenuated compared to the wild-type parent when administered orally to BALB/c mice and were less invasive in host tissues. Strains with ΔwaaG and ΔwaaI mutations, in particular, were deficient in colonization of Peyer's patches and liver. This deficiency could be partially overcome in the ΔwaaI mutant when it was administered intranasally. In the context of an attenuated vaccine strain delivering the pneumococcal antigen PspA, all of the mutations tested resulted in reduced immune responses against PspA and Salmonella antigens. Our results indicate that nonreversible truncation of the outer core is not a viable option for developing a live oral Salmonella vaccine, while a wzy mutant that retains one O-antigen unit is adequate for stimulating the optimal protective immunity to homologous or heterologous antigens by oral, intranasal, or intraperitoneal routes of administration.
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Chaudhari AA, Kim SW, Matsuda K, Lee JH. Safety Evaluation and Immunogenicity of Arabinose-Based Conditional Lethal Salmonella Gallinarum Mutant Unable to SurviveEx Vivoas a Vaccine Candidate for Protection Against Fowl Typhoid. Avian Dis 2011; 55:165-71. [DOI: 10.1637/9512-083010-reg.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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