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Harrell JE, Roy CJ, Gunn JS, McLachlan JB. Current vaccine strategies and novel approaches to combatting Francisella infection. Vaccine 2024; 42:2171-2180. [PMID: 38461051 DOI: 10.1016/j.vaccine.2024.02.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/23/2024] [Accepted: 02/27/2024] [Indexed: 03/11/2024]
Abstract
Tularemia is caused by subspecies of Francisella tularensis and can manifest in a variety of disease states, with the pneumonic presentation resulting in the greatest mortality. Despite decades of research, there are no approved vaccines against F. tularensis in the United States. Traditional vaccination strategies, such as live-attenuated or subunit vaccines, are not favorable due to inadequate protection or safety concerns. Because of this, novel vaccination strategies are needed to combat tularemia. Here we discuss the current state of and challenges to the tularemia vaccine field and suggest novel vaccine approaches going forward that might be better suited for protecting against F. tularensis infection.
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Affiliation(s)
- Jaikin E Harrell
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Chad J Roy
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - John S Gunn
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA, Infectious Diseases Institute, The Ohio State University, Columbus, Ohio, USA, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - James B McLachlan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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2
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Moradkasani S, Maurin M, Farrokhi AS, Esmaeili S. Development, Strategies, and Challenges for Tularemia Vaccine. Curr Microbiol 2024; 81:126. [PMID: 38564047 DOI: 10.1007/s00284-024-03658-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 03/01/2024] [Indexed: 04/04/2024]
Abstract
Francisella tularensis is a facultative intracellular bacterial pathogen that affects both humans and animals. It was developed into a biological warfare weapon as a result. In this article, the current status of tularemia vaccine development is presented. A live-attenuated vaccine that was designed over 50 years ago using the less virulent F. tularensis subspecies holarctica is the only prophylactic currently available, but it has not been approved for use in humans or animals. Other promising live, killed, and subunit vaccine candidates have recently been developed and tested in animal models. This study will investigate some possible vaccines and the challenges they face during development.
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Affiliation(s)
- Safoura Moradkasani
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Akanlu, KabudarAhang, Hamadan, Iran
- Department of Epidemiology and Biostatics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran
| | - Max Maurin
- CNRS, Grenoble INP, CHU Grenoble Alpes, TIMC-IMAG, Universite Grenoble Alpes, 38000, Grenoble, France
| | | | - Saber Esmaeili
- National Reference Laboratory for Plague, Tularemia and Q Fever, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Akanlu, KabudarAhang, Hamadan, Iran.
- Department of Epidemiology and Biostatics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran.
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3
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Zhao M, Zhai Y, Zai X, Mao Y, Hu E, Wei Z, Li Y, Li K, Liu Y, Xu J, Yu R, Chen W. Comparative evaluation of protective immunity against Francisella tularensis induced by subunit or adenovirus-vectored vaccines. Front Cell Infect Microbiol 2023; 13:1195314. [PMID: 37305410 PMCID: PMC10248143 DOI: 10.3389/fcimb.2023.1195314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/16/2023] [Indexed: 06/13/2023] Open
Abstract
Tularemia is a highly contagious disease caused by infection with Francisella tularensis (Ft), a pathogenic intracellular gram-negative bacterium that infects a wide range of animals and causes severe disease and death in people, making it a public health concern. Vaccines are the most effective way to prevent tularemia. However, there are no Food and Drug Administration (FDA)-approved Ft vaccines thus far due to safety concerns. Herein, three membrane proteins of Ft, Tul4, OmpA, and FopA, and a molecular chaperone, DnaK, were identified as potential protective antigens using a multifactor protective antigen platform. Moreover, the recombinant DnaK, FopA, and Tul4 protein vaccines elicited a high level of IgG antibodies but did not protect against challenge. In contrast, protective immunity was elicited by a replication-defective human type 5 adenovirus (Ad5) encoding the Tul4, OmpA, FopA, and DnaK proteins (Ad5-Tul4, Ad5-OmpA, Ad5-FopA, and Ad5-DnaK) after a single immunization, and all Ad5-based vaccines stimulated a Th1-biased immune response. Moreover, intramuscular and intranasal vaccination with Ad5-Tul4 using the prime-boost strategy effectively eliminated Ft lung, spleen and liver colonization and provided nearly 80% protection against intranasal challenge with the Ft live vaccine strain (LVS). Only intramuscular, not intranasal vaccination, with Ad5-Tul4 protected mice from intraperitoneal challenge. This study provides a comprehensive comparison of protective immunity against Ft provided by subunit or adenovirus-vectored vaccines and suggests that mucosal vaccination with Ad5-Tul4 may yield desirable protective efficacy against mucosal infection, while intramuscular vaccination offers greater overall protection against intraperitoneal tularemia.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Rui Yu
- *Correspondence: Rui Yu, ; Wei Chen,
| | - Wei Chen
- *Correspondence: Rui Yu, ; Wei Chen,
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Nagaratnam N, Martin-Garcia JM, Yang JH, Goode MR, Ketawala G, Craciunescu FM, Zook JD, Sonowal M, Williams D, Grant TD, Fromme R, Hansen DT, Fromme P. Structural and biophysical properties of FopA, a major outer membrane protein of Francisella tularensis. PLoS One 2022; 17:e0267370. [PMID: 35913965 PMCID: PMC9342783 DOI: 10.1371/journal.pone.0267370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is an extremely infectious pathogen and a category A bioterrorism agent. It causes the highly contagious zoonosis, Tularemia. Currently, FDA approved vaccines against tularemia are unavailable. F. tularensis outer membrane protein A (FopA) is a well-studied virulence determinant and protective antigen against tularemia. It is a major outer membrane protein (Omp) of F. tularensis. However, FopA-based therapeutic intervention is hindered due to lack of complete structural information for membrane localized mature FopA. In our study, we established recombinant expression, monodisperse purification, crystallization and X-ray diffraction (~6.5 Å) of membrane localized mature FopA. Further, we performed bioinformatics and biophysical experiments to unveil its structural organization in the outer membrane. FopA consists of 393 amino acids and has less than 40% sequence identity to known bacterial Omps. Using comprehensive sequence alignments and structure predictions together with existing partial structural information, we propose a two-domain organization for FopA. Circular dichroism spectroscopy and heat modifiability assay confirmed FopA has a β-barrel domain consistent with alphafold2’s prediction of an eight stranded β-barrel at the N-terminus. Small angle X-ray scattering (SAXS) and native-polyacrylamide gel electrophoresis revealed FopA purified in detergent micelles is predominantly dimeric. Molecular density derived from SAXS at 31 Å shows putative dimeric N-terminal β-barrels surrounded by detergent corona and connected to C-terminal domains via flexible linker. Disorder analysis predicts N- and C-terminal domains are interspersed by a long intrinsically disordered region and alphafold2 predicts this region to be largely unstructured. Taken together, we propose a dimeric, two-domain organization of FopA in the outer membrane: the N-terminal β-barrel is membrane embedded, provides dimerization interface and tethers to membrane extrinsic C-terminal domain via long flexible linker. Structure determination of membrane localized mature FopA is essential to understand its role in pathogenesis and develop anti-tularemia therapeutics. Our results pave the way towards it.
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Affiliation(s)
- Nirupa Nagaratnam
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jose M. Martin-Garcia
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jay-How Yang
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Matthew R. Goode
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Gihan Ketawala
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Felicia M. Craciunescu
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - James D. Zook
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Manashi Sonowal
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Dewight Williams
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Eyring Materials Center, Arizona State University, Tempe, Arizona, United States of America
| | - Thomas D. Grant
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, New York, New York, United States of America
| | - Raimund Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Debra T. Hansen
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Center for Innovations in Medicine, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Petra Fromme
- Center for Applied Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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Correia A, Alves P, Fróis-Martins R, Teixeira L, Vilanova M. Protective Effect against Neosporosis Induced by Intranasal Immunization with Neospora caninum Membrane Antigens Plus Carbomer-Based Adjuvant. Vaccines (Basel) 2022; 10:vaccines10060925. [PMID: 35746533 PMCID: PMC9230871 DOI: 10.3390/vaccines10060925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/04/2022] [Accepted: 06/08/2022] [Indexed: 02/01/2023] Open
Abstract
Neospora caninum is an obligate intracellular protozoan responsible for abortion and stillbirths in cattle. We previously developed a mucosal vaccination approach using N. caninum membrane proteins and CpG adjuvant that conferred long-term protection against neosporosis in mice. Here, we have extended this approach by alternatively using the carbomer-based adjuvant Carbigen™ in the immunizing preparation. Immunized mice presented higher proportions and numbers of memory CD4+ and CD8+ T cells. Stimulation of spleen, lungs and liver leukocytes with parasite antigens induced a marked production of IFN-γ and IL-17A and, less markedly, IL-4. This balanced response was also evident in that both parasite-specific IgG1 and IgG2c were raised by immunization, together with specific intestinal IgA. Upon intraperitoneal infection with N. caninum, immunized mice presented lower parasitic burdens than sham-immunized controls. In the infected immunized mice, memory CD4+ T cells predominantly expressed T-bet and RORγt, and CD8+ T cells expressing T-bet were found increased. While spleen, lungs and liver leukocytes of both immunized and sham-immunized infected animals produced high amounts of IFN-γ, only the cells from immunized mice responded with high IL-17A production. Since in cattle both IFN-γ and IL-17A have been associated with protective mechanisms against N. caninum infection, the elicited cytokine profile obtained using CarbigenTM as adjuvant indicates that it could be worth exploring for bovine neosporosis vaccination.
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Affiliation(s)
- Alexandra Correia
- ICBAS—Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (A.C.); (P.A.)
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135 Porto, Portugal
| | - Pedro Alves
- ICBAS—Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (A.C.); (P.A.)
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135 Porto, Portugal
| | - Ricardo Fróis-Martins
- Immunology Section, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland;
- Institute of Experimental Immunology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Luzia Teixeira
- UMIB—Unidade Multidisciplinar de Investigação Biomédica, ICBAS—Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 4050-313 Porto, Portugal;
- ITR—Laboratory for Integrative and Translational Research in Population Health, 4050-290 Porto, Portugal
| | - Manuel Vilanova
- ICBAS—Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (A.C.); (P.A.)
- I3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 4200-135 Porto, Portugal
- Correspondence:
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D'haeseleer P, Collette NM, Lao V, Segelke BW, Branda SS, Franco M. Shotgun Immunoproteomic Approach for the Discovery of Linear B-Cell Epitopes in Biothreat Agents Francisella tularensis and Burkholderia pseudomallei. Front Immunol 2021; 12:716676. [PMID: 34659206 PMCID: PMC8513525 DOI: 10.3389/fimmu.2021.716676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Peptide-based subunit vaccines are coming to the forefront of current vaccine approaches, with safety and cost-effective production among their top advantages. Peptide vaccine formulations consist of multiple synthetic linear epitopes that together trigger desired immune responses that can result in robust immune memory. The advantages of linear compared to conformational epitopes are their simple structure, ease of synthesis, and ability to stimulate immune responses by means that do not require complex 3D conformation. Prediction of linear epitopes through use of computational tools is fast and cost-effective, but typically of low accuracy, necessitating extensive experimentation to verify results. On the other hand, identification of linear epitopes through experimental screening has been an inefficient process that requires thorough characterization of previously identified full-length protein antigens, or laborious techniques involving genetic manipulation of organisms. In this study, we apply a newly developed generalizable screening method that enables efficient identification of B-cell epitopes in the proteomes of pathogenic bacteria. As a test case, we used this method to identify epitopes in the proteome of Francisella tularensis (Ft), a Select Agent with a well-characterized immunoproteome. Our screen identified many peptides that map to known antigens, including verified and predicted outer membrane proteins and extracellular proteins, validating the utility of this approach. We then used the method to identify seroreactive peptides in the less characterized immunoproteome of Select Agent Burkholderia pseudomallei (Bp). This screen revealed known Bp antigens as well as proteins that have not been previously identified as antigens. Although B-cell epitope prediction tools Bepipred 2.0 and iBCE-EL classified many of our seroreactive peptides as epitopes, they did not score them significantly higher than the non-reactive tryptic peptides in our study, nor did they assign higher scores to seroreactive peptides from known Ft or Bp antigens, highlighting the need for experimental data instead of relying on computational epitope predictions alone. The present workflow is easily adaptable to detecting peptide targets relevant to the immune systems of other mammalian species, including humans (depending upon the availability of convalescent sera from patients), and could aid in accelerating the discovery of B-cell epitopes and development of vaccines to counter emerging biological threats.
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Affiliation(s)
- Patrik D'haeseleer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Nicole M Collette
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Victoria Lao
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Brent W Segelke
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Steven S Branda
- Molecular and Microbiology Department, Sandia National Laboratories, Livermore, CA, United States
| | - Magdalena Franco
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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Feng J, Hu X, Fu M, Dai L, Yu Y, Luo W, Zhao Z, Lu Z, Du Z, Zhou D, Wen B, Jiao J, Xiong X. Enhanced protection against Q fever in BALB/c mice elicited by immunization of chloroform-methanol residue of Coxiella burnetii via intratracheal inoculation. Vaccine 2019; 37:6076-6084. [PMID: 31477436 DOI: 10.1016/j.vaccine.2019.08.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 08/07/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022]
Abstract
Human Q fever is recognized as a worldwide public health problem. It often occurs by inhalation of airborne aerosols contaminated with Coxiella burnetii, a gram-negative intracellular bacterium, mainly from domestic livestock. In this study, we analyzed the possibility to establish mucosal and systemic immunity against C. burnetii infection using a pulmonary delivery of chloroform-methanol residue of C. burnetii (CMR) vaccine. Mice were immunized by the intratracheal inoculation of CMR (IT-CMR) or the subcutaneous injection of CMR (SC-CMR), and the immunized mice were challenged with C. burnetii by the intratracheal route. The levels of IFN-γ, IL-12p70, IL-5, and IL-4 in the IT-CMR group in splenic T cells stimulated ex vivo were significantly higher than in the SC-CMR group. Significantly elevated sIgA to C. burnetii was detected in the bronchoalveolar lavage fluid of mice immunized by IT-CMR but not by SC-CMR, which might have contributed to the significant reduction in C. burnetii load and pathological lesions in the lungs of the mice after the challenge of C. burnetii. These results suggest that compared with SC-CMR in mice, IT-CMR was more efficient to elicit cellular and lung mucosal immune responses against aerosol infection of C. burnetii.
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Affiliation(s)
- Junxia Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Xueyuan Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Mengjiao Fu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Lupeng Dai
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Wenbo Luo
- Anhui Medical University, Mei-Shan Road, Hefei, Anhui 230032, China
| | - Zengming Zhao
- Center for Disease Control and Prevention of Chinese People's Liberation Army, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Zhiyu Lu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Zongmin Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Bohai Wen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China.
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China.
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Wang P, Škalamera Đ, Sui X, Zhang P, Michalek SM. Synthesis and Evaluation of QS-7-Based Vaccine Adjuvants. ACS Infect Dis 2019; 5:974-981. [PMID: 30920199 DOI: 10.1021/acsinfecdis.9b00039] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We have designed and synthesized two analogs (5 and 6) of QS-7, a natural saponin compound isolated from Quillaja saponaria (QS) Molina tree bark. The only structural difference between compound 5 and 6 is that 5 is acetylated at the 3- and 4-O positions of the quillaic acid C28 fucosyl unit while 6 is not. However, the two analogs show significantly different immunostimulant profiles. Compound 5 may potentiate a mixed Th1/Th2 (Th, T helper cells) immune response against the specific antigens while compound 6 may only induce a Th2-biased immunity. These results suggest that the 3- and/or 4-O acetyl groups of the fucosyl unit may play an important role in tuning the adjuvanticity of the QS-7 analogs, and compound 5 can serve as a structurally defined synthetic adjuvant when a mixed Th1/Th2 immune responses is desired.
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9
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Mansour AA, Banik S, Suresh RV, Kaur H, Malik M, McCormick AA, Bakshi CS. An Improved Tobacco Mosaic Virus (TMV)-Conjugated Multiantigen Subunit Vaccine Against Respiratory Tularemia. Front Microbiol 2018; 9:1195. [PMID: 29922267 PMCID: PMC5996085 DOI: 10.3389/fmicb.2018.01195] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Francisella tularensis, the causative agent of the fatal human disease known as tularemia is classified as a Category A Select Agent by the Centers for Disease Control. No licensed vaccine is currently available for prevention of tularemia in the United States. Previously, we published that a tri-antigen tobacco mosaic virus (TMV) vaccine confers 50% protection in immunized mice against respiratory tularemia caused by F. tularensis. In this study, we refined the TMV-vaccine formulation to improve the level of protection in immunized C57BL/6 mice against respiratory tularemia. We developed a tetra-antigen vaccine by conjugating OmpA, DnaK, Tul4, and SucB proteins of Francisella to TMV. CpG was also included in the vaccine formulation as an adjuvant. Primary intranasal (i.n.) immunization followed by two booster immunizations with the tetra-antigen TMV vaccine protected 100% mice against i.n. 10LD100 challenges dose of F. tularensis live vaccine strain (LVS). Mice receiving three immunization doses of tetra-antigen TMV vaccine showed only transient body weight loss, cleared the infection rapidly, and showed minimal histopathological lesions in lungs, liver, and spleen following a lethal respiratory challenge with F. tularensis LVS. Mice immunized with the tetra-antigen TMV vaccine also induced strong ex vivo recall responses and were protected against a lethal challenge as late as 163 days post-primary immunization. Three immunization with the tetra-antigen TMV vaccine also induced a stronger humoral immune response predominated by IgG1, IgG2b, and IgG2c antibodies than mice receiving only a single or two immunizations. Remarkably, a single dose protected 40% of mice, while two doses protected 80% of mice from lethal pathogen challenge. Immunization of Interferon-gamma (IFN-γ)-deficient mice with the tetra-antigen TMV vaccine demonstrated an absolute requirement of IFN-γ for the generation of protective immune response against a lethal respiratory challenge with F. tularensis LVS. Collectively, this study further demonstrates the feasibility of TMV as an efficient platform for the delivery of multiple F. tularensis antigens and that tetra-antigen TMV vaccine formulation provides complete protection, and induces long-lasting protective and memory immune responses against respiratory tularemia caused by F. tularensis LVS.
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Affiliation(s)
- Ahd A Mansour
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Sukalyani Banik
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Ragavan V Suresh
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Hardeep Kaur
- College of Pharmacy, Touro University California, Vallejo, CA, United States
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, School of Arts and Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Alison A McCormick
- College of Pharmacy, Touro University California, Vallejo, CA, United States
| | - Chandra S Bakshi
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
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10
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McCormick AA, Shakeel A, Yi C, Kaur H, Mansour AM, Bakshi CS. Intranasal administration of a two-dose adjuvanted multi-antigen TMV-subunit conjugate vaccine fully protects mice against Francisella tularensis LVS challenge. PLoS One 2018; 13:e0194614. [PMID: 29684046 PMCID: PMC5912714 DOI: 10.1371/journal.pone.0194614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/06/2018] [Indexed: 12/03/2022] Open
Abstract
Tularemia is a fatal human disease caused by Francisella tularensis, a Gram-negative encapsulated coccobacillus bacterium. Due to its low infectious dose, ease of aerosolized transmission, and lethal effects, the CDC lists F. tularensis as a Category A pathogen, the highest level for a potential biothreat agent. Previous vaccine studies have been conducted with live attenuated, inactivated, and subunit vaccines, which have achieved partial or full protection from F. tularensis live vaccine strain (LVS) challenge, but no vaccine has been approved for human use. We demonstrate the improved efficacy of a multi-antigen subunit vaccine by using Tobacco Mosaic virus (TMV) as an antigen carrier for the F. tularensis SchuS4 proteins DnaK, OmpA, SucB and Tul4 (DOST). The magnitude and quality of immune responses were compared after mice were immunized by subcutaneous or intranasal routes of administration with a TMV-DOST mixture, with or without four different adjuvants. Immune responses varied in magnitude and isotype profile, by antigen, by route of administration, and by protection in an F. tularensis LVS challenge model of disease. Interestingly, our analysis demonstrates an overwhelming IgG2 response to SucB after intranasal dosing, as well as a robust cellular response, which may account for the improved two-dose survival imparted by the tetravalent vaccine, compared to a previous study that tested efficacy of TMV-DOT. Our study provides evidence that potent humoral, cellular and mucosal immunity can be achieved by optimal antigen combination, delivery, adjuvant and appropriate route of administration, to improve vaccine potency and provide protection from pathogen challenge.
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MESH Headings
- Adjuvants, Immunologic
- Administration, Intranasal
- Animals
- Antibodies, Bacterial/analysis
- Antibodies, Bacterial/metabolism
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Bacterial Proteins/metabolism
- Bacterial Vaccines/immunology
- Disease Models, Animal
- Female
- Francisella tularensis/immunology
- Immunity, Cellular
- Immunoglobulin G/analysis
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Immunoglobulin Isotypes/immunology
- Immunoglobulin Isotypes/metabolism
- Mice
- Mice, Inbred C57BL
- Survival Rate
- Tobacco Mosaic Virus/genetics
- Tobacco Mosaic Virus/metabolism
- Tularemia/immunology
- Tularemia/microbiology
- Tularemia/prevention & control
- Vaccines, Conjugate/immunology
- Vaccines, Subunit/immunology
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Affiliation(s)
| | - Aisha Shakeel
- Touro University California, College of Pharmacy, Vallejo, CA
| | - Chris Yi
- Touro University California, College of Pharmacy, Vallejo, CA
| | - Hardeep Kaur
- Touro University California, College of Pharmacy, Vallejo, CA
| | - Ahd M. Mansour
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY
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11
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Post DMB, Slütter B, Schilling B, Chande AT, Rasmussen JA, Jones BD, D'Souza AK, Reinders LM, Harty JT, Gibson BW, Apicella MA. Characterization of Inner and Outer Membrane Proteins from Francisella tularensis Strains LVS and Schu S4 and Identification of Potential Subunit Vaccine Candidates. mBio 2017; 8:e01592-17. [PMID: 29018123 PMCID: PMC5635693 DOI: 10.1128/mbio.01592-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/06/2017] [Indexed: 01/02/2023] Open
Abstract
Francisella tularensis is the causative agent of tularemia and a potential bioterrorism agent. In the present study, we isolated, identified, and quantified the proteins present in the membranes of the virulent type A strain, Schu S4, and the attenuated type B strain, LVS (live vaccine strain). Spectral counting of mass spectrometric data showed enrichment for membrane proteins in both strains. Mice vaccinated with whole LVS membranes encapsulated in poly (lactic-co-glycolic acid) (PLGA) nanoparticles containing the adjuvant polyinosinic-polycytidylic acid [poly(I·C)] showed significant protection against a challenge with LVS compared to the results seen with naive mice or mice vaccinated with either membranes or poly(I·C) alone. The PLGA-encapsulated Schu S4 membranes with poly(I·C) alone did not significantly protect mice from a lethal intraperitoneal challenge with Schu S4; however, this vaccination strategy provided protection from LVS challenge. Mice that received the encapsulated Schu S4 membranes followed by a booster of LVS bacteria showed significant protection with respect to a lethal Schu S4 challenge compared to control mice. Western blot analyses of the sera from the Schu S4-vaccinated mice that received an LVS booster showed four immunoreactive bands. One of these bands from the corresponding one-dimensional (1D) SDS-PAGE experiment represented capsule. The remaining bands were excised, digested with trypsin, and analyzed using mass spectrometry. The most abundant proteins present in these immunoreactive samples were an outer membrane OmpA-like protein, FopA; the type IV pilus fiber building block protein; a hypothetical membrane protein; and lipoproteins LpnA and Lpp3. These proteins should serve as potential targets for future recombinant protein vaccination studies.IMPORTANCE The low infectious dose, the high potential mortality/morbidity rates, and the ability to be disseminated as an aerosol make Francisella tularensis a potential agent for bioterrorism. These characteristics led the Centers for Disease Control (CDC) to classify F. tularensis as a Tier 1 pathogen. Currently, there is no vaccine approved for general use in the United States.
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Affiliation(s)
| | - Bram Slütter
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
| | | | - Aroon T Chande
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
| | - Jed A Rasmussen
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
| | - Bradley D Jones
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
| | | | | | - John T Harty
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
| | - Bradford W Gibson
- Buck Institute for Research on Aging, Novato, California, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, USA
| | - Michael A Apicella
- Department of Microbiology, the University of Iowa, Iowa City, Iowa, USA
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12
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Patil HP, Herrera Rodriguez J, de Vries-Idema J, Meijerhof T, Frijlink HW, Hinrichs WLJ, Huckriede A. Adjuvantation of Pulmonary-Administered Influenza Vaccine with GPI-0100 Primarily Stimulates Antibody Production and Memory B Cell Proliferation. Vaccines (Basel) 2017; 5:vaccines5030019. [PMID: 28749414 PMCID: PMC5620550 DOI: 10.3390/vaccines5030019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/19/2017] [Accepted: 07/21/2017] [Indexed: 11/24/2022] Open
Abstract
Adjuvants are key components in vaccines, they help in reducing the required antigen dose but also modulate the phenotype of the induced immune response. We previously showed that GPI-0100, a saponin-derived adjuvant, enhances antigen-specific mucosal and systemic antibody responses to influenza subunit and whole inactivated influenza virus (WIV) vaccine administered via the pulmonary route. However, the impact of the GPI-0100 dose on immune stimulation and the immune mechanisms stimulated by GPI-0100 along with antigen are poorly understood. Therefore, in this study we immunized C57BL/6 mice via the pulmonary route with vaccine consisting of WIV combined with increasing amounts of GPI-0100, formulated as a dry powder. Adjuvantation of WIV enhanced influenza-specific mucosal and systemic immune responses, with intermediate doses of 5 and 7.5 μg GPI-0100 being most effective. The predominant antibody subtype induced by GPI-0100-adjuvanted vaccine was IgG1. Compared to non-adjuvanted vaccine, GPI-0100-adjuvanted WIV vaccine gave rise to higher numbers of antigen-specific IgA- but not IgG-producing B cells in the lungs along with better mucosal and systemic memory B cell responses. The GPI-0100 dose was negatively correlated with the number of influenza-specific IFNγ- and IL17-producing T cells and positively correlated with the number of IL4-producing T cells observed after immunization and challenge. Overall, our results show that adjuvantation of pulmonary-delivered WIV with GPI-0100 mostly affects B cell responses and effectively induces B cell memory.
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Affiliation(s)
- Harshad P Patil
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
- Department of Communicable Diseases, Interactive Research School for Health Affairs, Bharati Vidyapeeth University, Pune-Satara Road, Katraj-Dhankawadi, Pune 411043, Maharashtra, India.
| | - José Herrera Rodriguez
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Jacqueline de Vries-Idema
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Tjarko Meijerhof
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Henderik W Frijlink
- Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Wouter L J Hinrichs
- Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Anke Huckriede
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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Monophosphoryl Lipid A Enhances Efficacy of a Francisella tularensis LVS-Catanionic Nanoparticle Subunit Vaccine against F. tularensis Schu S4 Challenge by Augmenting both Humoral and Cellular Immunity. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00574-16. [PMID: 28077440 DOI: 10.1128/cvi.00574-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/06/2017] [Indexed: 01/01/2023]
Abstract
Francisella tularensis, a bacterial biothreat agent, has no approved vaccine in the United States. Previously, we showed that incorporating lysates from partially attenuated F. tularensis LVS or fully virulent F. tularensis Schu S4 strains into catanionic surfactant vesicle (V) nanoparticles (LVS-V and Schu S4-V, respectively) protected fully against F. tularensis LVS intraperitoneal (i.p.) challenge in mice. However, we achieved only partial protection against F. tularensis Schu S4 intranasal (i.n.) challenge, even when employing heterologous prime-boost immunization strategies. We now extend these findings to show that both LVS-V and Schu S4-V immunization (i.p./i.p.) elicited similarly high titers of anti-F. tularensis IgG and that the titers could be further increased by adding monophosphoryl lipid A (MPL), a nontoxic Toll-like receptor 4 (TLR4) adjuvant that is included in several U.S. FDA-approved vaccines. LVS-V+MPL immune sera also detected more F. tularensis antigens than LVS-V immune sera and, after passive transfer to naive mice, significantly delayed the time to death against F. tularensis Schu S4 subcutaneous (s.c.) but not i.n. challenge. Active immunization with LVS-V+MPL (i.p./i.p.) also increased the frequency of gamma interferon (IFN-γ)-secreting activated helper T cells, IFN-γ production, and the ability of splenocytes to control intramacrophage F. tularensis LVS replication ex vivo Active LVS-V+MPL immunization via heterologous routes (i.p./i.n.) significantly elevated IgA and IgG levels in bronchoalveolar lavage fluid and significantly enhanced protection against i.n. F. tularensis Schu S4 challenge (to ∼60%). These data represent a significant step in the development of a subunit vaccine against the highly virulent type A strains.
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14
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Abstract
Francisella tularensis is the causative agent of the potentially lethal disease tularemia. Due to a low infectious dose and ease of airborne transmission, Francisella is classified as a category A biological agent. Despite the possible risk to public health, there is no safe and fully licensed vaccine. A potential vaccine candidate, an attenuated live vaccine strain, does not fulfil the criteria for general use. In this review, we will summarize existing and new candidates for live attenuated and subunit vaccines.
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15
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Abstract
Francisella tularensis (Ft) is a gram-negative intercellular pathogen and category A biothreat agent. However, despite 15 years of strong government investment and intense research focused on the development of a US Food and Drug Administration-approved vaccine against Ft, the primary goal remains elusive. This article reviews research efforts focused on developing an Ft vaccine, as well as a number of important factors, some only recently recognized as such, which can significantly impact the development and evaluation of Ft vaccine efficacy. Finally, an assessment is provided as to whether a US Food and Drug Administration-approved Ft vaccine is likely to be forthcoming and the potential means by which this might be achieved.
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Affiliation(s)
- Raju Sunagar
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - Sudeep Kumar
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - Brian J Franz
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - Edmund J Gosselin
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
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16
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Development of a Multivalent Subunit Vaccine against Tularemia Using Tobacco Mosaic Virus (TMV) Based Delivery System. PLoS One 2015; 10:e0130858. [PMID: 26098553 PMCID: PMC4476615 DOI: 10.1371/journal.pone.0130858] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/26/2015] [Indexed: 11/21/2022] Open
Abstract
Francisella tularensis is a facultative intracellular pathogen, and is the causative agent of a fatal human disease known as tularemia. F. tularensis is classified as a Category A Biothreat agent by the CDC based on its use in bioweapon programs by several countries in the past and its potential to be used as an agent of bioterrorism. No licensed vaccine is currently available for prevention of tularemia. In this study, we used a novel approach for development of a multivalent subunit vaccine against tularemia by using an efficient tobacco mosaic virus (TMV) based delivery platform. The multivalent subunit vaccine was formulated to contain a combination of F. tularensis protective antigens: OmpA-like protein (OmpA), chaperone protein DnaK and lipoprotein Tul4 from the highly virulent F. tularensis SchuS4 strain. Two different vaccine formulations and immunization schedules were used. The immunized mice were challenged with lethal (10xLD100) doses of F. tularensis LVS on day 28 of the primary immunization and observed daily for morbidity and mortality. Results from this study demonstrate that TMV can be used as a carrier for effective delivery of multiple F. tularensis antigens. TMV-conjugate vaccine formulations are safe and multiple doses can be administered without causing any adverse reactions in immunized mice. Immunization with TMV-conjugated F. tularensis proteins induced a strong humoral immune response and protected mice against respiratory challenges with very high doses of F. tularensis LVS. This study provides a proof-of-concept that TMV can serve as a suitable platform for simultaneous delivery of multiple protective antigens of F. tularensis. Refinement of vaccine formulations coupled with TMV-targeting strategies developed in this study will provide a platform for development of an effective tularemia subunit vaccine as well as a vaccination approach that may broadly be applicable to many other bacterial pathogens.
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17
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Suresh RV, Ma Z, Sunagar R, Bhatty V, Banik S, Catlett SV, Gosselin EJ, Malik M, Bakshi CS. Preclinical testing of a vaccine candidate against tularemia. PLoS One 2015; 10:e0124326. [PMID: 25897786 PMCID: PMC4405390 DOI: 10.1371/journal.pone.0124326] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/02/2015] [Indexed: 11/18/2022] Open
Abstract
Tularemia is caused by a gram-negative, intracellular bacterial pathogen, Francisella tularensis (Ft). The history weaponization of Ft in the past has elevated concerns that it could be used as a bioweapon or an agent of bioterrorism. Since the discovery of Ft, three broad approaches adopted for tularemia vaccine development have included inactivated, live attenuated, or subunit vaccines. Shortcomings in each of these approaches have hampered the development of a suitable vaccine for prevention of tularemia. Recently, we reported an oxidant sensitive mutant of Ft LVS in putative EmrA1 (FTL_0687) secretion protein. The emrA1 mutant is highly sensitive to oxidants, attenuated for intramacrophage growth and virulence in mice. We reported that EmrA1 contributes to oxidant resistance by affecting the secretion of antioxidant enzymes SodB and KatG. This study investigated the vaccine potential of the emrA1 mutant in prevention of respiratory tularemia caused by Ft LVS and the virulent SchuS4 strain in C57BL/6 mice. We report that emrA1 mutant is safe and can be used at an intranasal (i. n.) immunization dose as high as 1x106 CFU without causing any adverse effects in immunized mice. The emrA1 mutant is cleared by vaccinated mice by day 14-21 post-immunization, induces minimal histopathological lesions in lungs, liver and spleen and a strong humoral immune response. The emrA1 mutant vaccinated mice are protected against 1000-10,000LD100 doses of i.n. Ft LVS challenge. Such a high degree of protection has not been reported earlier against respiratory challenge with Ft LVS using a single immunization dose with an attenuated mutant generated on Ft LVS background. The emrA1 mutant also provides partial protection against i.n. challenge with virulent Ft SchuS4 strain in vaccinated C57BL/6 mice. Collectively, our results further support the notion that antioxidants of Ft may serve as potential targets for development of effective vaccines for prevention of tularemia.
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Affiliation(s)
| | - Zhuo Ma
- Albany College of Pharmacy and Health Sciences, Albany, United States of America
| | - Raju Sunagar
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, United States of America
| | - Vivek Bhatty
- Department of Microbiology and Immunology, New York Medical College, Valhalla, United States of America
| | - Sukalyani Banik
- Department of Microbiology and Immunology, New York Medical College, Valhalla, United States of America
| | - Sally V. Catlett
- Albany College of Pharmacy and Health Sciences, Albany, United States of America
| | - Edmund J. Gosselin
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, United States of America
| | - Meenakshi Malik
- Albany College of Pharmacy and Health Sciences, Albany, United States of America
- * E-mail: (MM); (CSB)
| | - Chandra Shekhar Bakshi
- Department of Microbiology and Immunology, New York Medical College, Valhalla, United States of America
- * E-mail: (MM); (CSB)
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18
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Kubelkova K, Macela A. Putting the Jigsaw Together - A Brief Insight Into the Tularemia. Open Life Sci 2015. [DOI: 10.1515/biol-2015-0013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
AbstractTularemia is a debilitating febrile and potentially fatal zoonotic disease of humans and other vertebrates caused by the Gram-negative bacterium Francisella tularensis. The natural reservoirs are small rodents, hares, and possibly amoebas in water. The etiological agent, Francisella tularensis, is a non-spore forming, encapsulated, facultative intracellular bacterium, a member of the γ-Proteobacteria class of Gram-negative bacteria. Francisella tularensis is capable of invading and replicating within phagocytic as well as non-phagocytic cells and modulate inflammatory response. Infection by the pulmonary, dermal, or oral routes, respectively, results in pneumonic, ulceroglandular, or oropharyngeal tularemia. The highest mortality rates are associated with the pneumonic form of this disease. All members of Francisella tularensis species cause more or less severe disease Due to their abilities to be transmitted to humans via multiple routes and to be disseminated via biological aerosol that can cause the disease after inhalation of even an extremely low infectious dose, Francisella tularensis has been classified as a Category A bioterrorism agent. The current standard of care for tularemia is treatment with antibiotics, as this therapy is highly effective if used soon after infection, although it is not, however, absolutely effective in all cases.
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19
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Ren G, Champion MM, Huntley JF. Identification of disulfide bond isomerase substrates reveals bacterial virulence factors. Mol Microbiol 2014; 94:926-44. [PMID: 25257164 DOI: 10.1111/mmi.12808] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2014] [Indexed: 01/22/2023]
Abstract
Bacterial pathogens are exposed to toxic molecules inside the host and require efficient systems to form and maintain correct disulfide bonds for protein stability and function. The intracellular pathogen Francisella tularensis encodes a disulfide bond formation protein ortholog, DsbA, which previously was reported to be required for infection of macrophages and mice. However, the molecular mechanisms by which F. tularensis DsbA contributes to virulence are unknown. Here, we demonstrate that F. tularensis DsbA is a bifunctional protein that oxidizes and, more importantly, isomerizes complex disulfide connectivity in substrates. A single amino acid in the conserved cis-proline loop of the DsbA thioredoxin domain was shown to modulate both isomerase activity and F. tularensis virulence. Trapping experiments in F. tularensis identified over 50 F. tularensis DsbA substrates, including outer membrane proteins, virulence factors, and many hypothetical proteins. Six of these hypothetical proteins were randomly selected and deleted, revealing two novel proteins, FTL_1548 and FTL_1709, which are required for F. tularensis virulence. We propose that the extreme virulence of F. tularensis is partially due to the bifunctional nature of DsbA, that many of the newly identified substrates are required for virulence, and that the development of future DsbA inhibitors could have broad anti-bacterial implications.
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Affiliation(s)
- Guoping Ren
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, 43614, USA
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20
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Griffiths KL, Khader SA. Novel vaccine approaches for protection against intracellular pathogens. Curr Opin Immunol 2014; 28:58-63. [PMID: 24608070 DOI: 10.1016/j.coi.2014.02.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 12/21/2022]
Abstract
Vaccination against intracellular pathogens requires generation of a pool of memory T cells able to respond upon infection and mediate either killing of the infected cell or induce killing mechanisms in the infected cell. T cell-inducing vaccines must aim to target the antigen to antigen-presenting cells (APCs) so that it can be presented on MHC molecules on the cell surface. Methods to do this include making use of vectors such as plasmid DNA or viruses, live attenuated pathogens or subunit vaccines targeted and enhanced using adjuvants. The choice of approach should be guided by the phenotype and localization of the desired T cell response. This review will discuss current approaches in the pipeline for the development of T cell-inducing vaccines, including vectored, live attenuated, and subunit vaccines.
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Affiliation(s)
- Kristin L Griffiths
- Department of Molecular Microbiology, Campus Box 8230, 660 South Euclid Avenue, St. Louis, MO 63110-1093, USA
| | - Shabaana A Khader
- Department of Molecular Microbiology, Campus Box 8230, 660 South Euclid Avenue, St. Louis, MO 63110-1093, USA.
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21
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Novel catanionic surfactant vesicle vaccines protect against Francisella tularensis LVS and confer significant partial protection against F. tularensis Schu S4 strain. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 21:212-26. [PMID: 24351755 DOI: 10.1128/cvi.00738-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Francisella tularensis is a Gram-negative immune-evasive coccobacillus that causes tularemia in humans and animals. A safe and efficacious vaccine that is protective against multiple F. tularensis strains has yet to be developed. In this study, we tested a novel vaccine approach using artificial pathogens, synthetic nanoparticles made from catanionic surfactant vesicles that are functionalized by the incorporation of either F. tularensis type B live vaccine strain (F. tularensis LVS [LVS-V]) or F. tularensis type A Schu S4 strain (F. tularensis Schu S4 [Schu S4-V]) components. The immunization of C57BL/6 mice with "bare" vesicles, which did not express F. tularensis components, partially protected against F. tularensis LVS, presumably through activation of the innate immune response, and yet it failed to protect against the F. tularensis Schu S4 strain. In contrast, immunization with LVS-V fully protected mice against intraperitoneal (i.p.) F. tularensis LVS challenge, while immunization of mice with either LVS-V or Schu S4-V partially protected C57BL/6 mice against an intranasal (i.n.) F. tularensis Schu S4 challenge and significantly increased the mean time to death for nonsurvivors, particularly following the i.n. and heterologous (i.e., i.p./i.n.) routes of immunization. LVS-V immunization, but not immunization with empty vesicles, elicited high levels of IgG against nonlipopolysaccharide (non-LPS) epitopes that were increased after F. tularensis LVS challenge and significantly increased early cytokine production. Antisera from LVS-V-immunized mice conferred passive protection against challenge with F. tularensis LVS. Together, these data indicate that functionalized catanionic surfactant vesicles represent an important and novel tool for the development of a safe and effective F. tularensis subunit vaccine and may be applicable for use with other pathogens.
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Jaiswal V, Chauhan RS, Rout C. Common antigens prediction in bacterial bioweapons: a perspective for vaccine design. INFECTION GENETICS AND EVOLUTION 2013; 21:315-9. [PMID: 24300889 DOI: 10.1016/j.meegid.2013.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 11/10/2013] [Accepted: 11/11/2013] [Indexed: 01/22/2023]
Abstract
Bioweapons (BWs) are a serious threat to mankind and the lack of efficient vaccines against bacterial bioweapons (BBWs) further worsens the situation in face of BW attack. Experts believe that difficulties in detection and ease in dissemination of deadly pathogens make BW a better option for attack compared to nuclear weapons. Molecular biology techniques facilitate the use of genetically modified BBWs thus creating uncertainty on which bacteria will be used for BW attack. In the present work, available resources such as proteomic sequences of BBWs, protective antigenic proteins (PAPs) reported in Protegen database and VaxiJen dataset, and immunogenic epitopes in immune epitope database (IEDB) were used to predict potential broad-specific vaccine candidates against BBWs. Comparison of proteomes sequences of BBWs and their analyses using in-house PERL scripts identified 44 conserved proteins and many of them were known to be immunogenic. Comparison of conserved proteins against PAPs identified six either as PAPs or their homologues with a potential of providing protection against multiple pathogens. Similarly, mapping of conserved proteins against experimentally known IEDB epitopes identified six epitopes which had exact epitope match in four proteins including three from earlier predicted six PAPs. These epitopes were also reported to provide protection against several pathogens. In the backdrop of conserved heat shock GroEL protein from Salmonella enterica providing protection against five diverse bacterial pathogens involved in different diseases, and synthetic proteins produced by combination of epitopes from Mycobacterium tuberculosis and 4 viruses providing protection against both bacterium and viruses, the identified putative immunogenic conserved proteins and immune-protective epitopes can further be explored for their potential as broad-specific vaccine candidates against BBWs.
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Affiliation(s)
- Varun Jaiswal
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234, India.
| | - Rajinder S Chauhan
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234, India.
| | - Chittaranjan Rout
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234, India.
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da Silva AJ, Horta ACL, Velez AM, Iemma MRC, Sargo CR, Giordano RL, Novo MTM, Giordano RC, Zangirolami TC. Non-conventional induction strategies for production of subunit swine erysipelas vaccine antigen in rE. coli fed-batch cultures. SPRINGERPLUS 2013; 2:322. [PMID: 23961396 PMCID: PMC3724991 DOI: 10.1186/2193-1801-2-322] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 06/23/2013] [Indexed: 11/10/2022]
Abstract
In spite of the large number of reports on fed-batch cultivation of E. coli, alternative cultivation/induction strategies remain to be more deeply exploited. Among these strategies, it could be mentioned the use of complex media with combination of different carbon sources, novel induction procedures and feed flow rate control matching the actual cell growth rate. Here, four different carbon source combinations (glucose, glycerol, glucose + glycerol and auto-induction) in batch media formulation were compared. A balanced combination of glucose and glycerol in a complex medium formulation led to: fast growth in the batch-phase; reduced plasmid instability by preventing early expression leakage; and protein volumetric productivity of 0.40 g.L-1.h-1. Alternative induction strategies were also investigated. A mixture of lactose and glycerol as supplementary medium fully induced a high biomass population, reaching a good balance between specific protein production (0.148 gprot.gDCW-1) and volumetric productivity (0.32 g.L-1.h-1). The auto-induction protocol showed excellent results on specific protein production (0.158 gprot.gDCW-1) in simple batch cultivations. An automated feed control based on the on-line estimated growth rate was implemented, which allowed cells to grow at higher rates than those generally used to avoid metabolic overflow, without leading to acetate accumulation. Some of the protocols described here may provide a useful alternative to standard cultivation and recombinant protein production processes, depending on the performance index that is expected to be optimized. The protocols using glycerol as carbon source and induction by lactose feeding, or glycerol plus glucose in batch medium and induction by lactose pulse led to rSpaA production in the range of 6 g.L-1, in short fed-batch processes (16 to 20 h) with low accumulation of undesired side metabolites.
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Affiliation(s)
- Adilson José da Silva
- Chemical Engineering Department, Federal University of São Carlos, Rodovia Washington Luís, km 235, São Carlos, SP Brazil
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