1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Postnikova E, Liang J, Yu S, Cai Y, Cong Y, Holbrook MR. Anti-Nipah Virus Enzyme-Linked Immunosorbent Assays with Non-human Primate and Hamster Serum. Methods Mol Biol 2023; 2682:233-244. [PMID: 37610586 DOI: 10.1007/978-1-0716-3283-3_17] [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] [Indexed: 08/24/2023]
Abstract
Enzyme-linked Immunosorbent assays or ELISAs are a versatile method for detecting various immunological ligands of interest. As the name suggests, ELISAs rely on the interaction between a ligand and an antibody to produce results. In the study of infectious disease, ELISAs are commonly used to determine if a pathogen-specific immune response has occurred in a host organism. These assays can be performed in serosurveys as part of epidemiological investigations during, or following, an infectious disease outbreak. In the research environment, ELISAs are used to quantify the humoral immune response following infection or vaccination of a host organism. Data from these assays can be used to determine the type of immune response elicited (e.g. IgG1 vs IgG2) and the robustness of the response. Here, we describe ELISAs that were developed for the study of either hamsters or non-human primates vaccinated against Nipah virus infection, or infected with Nipah virus. The ELISAs described include assays for both IgG and IgM in the hamster and non-human primate models for Nipah virus-induced disease. An assay was also developed for the detection of IgA in bronchoalveolar lavage from non-human primates.
Collapse
Affiliation(s)
- Elena Postnikova
- NIAID Integrated Research Facility, Ft. Detrick, Frederick, MD, USA
| | - Janie Liang
- NIAID Integrated Research Facility, Ft. Detrick, Frederick, MD, USA
| | - Shuiqing Yu
- NIAID Integrated Research Facility, Ft. Detrick, Frederick, MD, USA
| | - Yingyun Cai
- NIAID Integrated Research Facility, Ft. Detrick, Frederick, MD, USA
| | - Yu Cong
- NIAID Integrated Research Facility, Ft. Detrick, Frederick, MD, USA
| | | |
Collapse
|
3
|
Swietnicki W. Secretory System Components as Potential Prophylactic Targets for Bacterial Pathogens. Biomolecules 2021; 11:892. [PMID: 34203937 PMCID: PMC8232601 DOI: 10.3390/biom11060892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/13/2021] [Accepted: 06/14/2021] [Indexed: 01/18/2023] Open
Abstract
Bacterial secretory systems are essential for virulence in human pathogens. The systems have become a target of alternative antibacterial strategies based on small molecules and antibodies. Strategies to use components of the systems to design prophylactics have been less publicized despite vaccines being the preferred solution to dealing with bacterial infections. In the current review, strategies to design vaccines against selected pathogens are presented and connected to the biology of the system. The examples are given for Y. pestis, S. enterica, B. anthracis, S. flexneri, and other human pathogens, and discussed in terms of effectiveness and long-term protection.
Collapse
Affiliation(s)
- Wieslaw Swietnicki
- Department of Immunology of Infectious Diseases, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114 Wroclaw, Poland
| |
Collapse
|
4
|
Shahin K, Shinn AP, Metselaar M, Ramirez-Paredes JG, Monaghan SJ, Thompson KD, Hoare R, Adams A. Efficacy of an inactivated whole-cell injection vaccine for nile tilapia, Oreochromis niloticus (L), against multiple isolates of Francisella noatunensis subsp. orientalis from diverse geographical regions. FISH & SHELLFISH IMMUNOLOGY 2019; 89:217-227. [PMID: 30951851 DOI: 10.1016/j.fsi.2019.03.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/26/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
Francisellosis, induced by Francisella noatunensis subsp. orientalis (Fno), is an emerging bacterial disease representing a major threat to the global tilapia industry. There are no commercialised vaccines presently available against francisellosis for use in farmed tilapia, and the only available therapeutic practices used in the field are either the prolonged use of antibiotics or increasing water temperature. Recently, an autogenous whole cell-adjuvanted injectable vaccine was developed that gave 100% relative percent survival (RPS) in tilapia challenged with a homologous isolate of Fno. In this study, we evaluated the efficacy of this vaccine against challenge with heterologous Fno isolates. Healthy Nile tilapia, Oreochromis niloticus (∼15 g) were injected intraperitoneally (i.p.) with the vaccine, adjuvant-alone or phosphate buffer saline (PBS) followed by an i.p. challenge with three Fno isolates from geographically distinct locations. The vaccine provided significant protection in all groups of vaccinated tilapia, with a significantly higher RPS of 82.3% obtained against homologous challenge, compared to 69.8% and 65.9% with the heterologous challenges. Protection correlated with significantly higher specific antibody responses, and western blot analysis demonstrated cross-isolate antigenicity with fish sera post-vaccination and post-challenge. Moreover, a significantly lower bacterial burden was detected by qPCR in conjunction with significantly greater expression of IgM, IL-1 β, TNF-α and MHCII, 72 h post-vaccination (hpv) in spleen samples from vaccinated tilapia compared to fish injected with adjuvant-alone and PBS. The Fno vaccine described in this study may provide a starting point for development a broad-spectrum highly protective vaccine against francisellosis in tilapia.
Collapse
Affiliation(s)
- Khalid Shahin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK; Aquatic Animal Diseases Lab, Aquaculture Department, National Institute of Oceanography and Fisheries (NIOF), P.O. Box 43511, Suez, Egypt.
| | - Andrew P Shinn
- Fish Vet Group Asia, 21/359 Premjairard Road, Chonburi, 20130, Thailand
| | - Matthijs Metselaar
- Benchmark Animal Health, Bush House, Edinburgh Technopole, Midlothian, Edinburgh, EH26 0BB, UK
| | | | - Sean J Monaghan
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Kim D Thompson
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK
| | - Rowena Hoare
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| | - Alexandra Adams
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK
| |
Collapse
|
5
|
Jia Q, Horwitz MA. Live Attenuated Tularemia Vaccines for Protection Against Respiratory Challenge With Virulent F. tularensis subsp. tularensis. Front Cell Infect Microbiol 2018; 8:154. [PMID: 29868510 PMCID: PMC5963219 DOI: 10.3389/fcimb.2018.00154] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/24/2018] [Indexed: 12/11/2022] Open
Abstract
Francisella tularensis is the causative agent of tularemia and a Tier I bioterrorism agent. In the 1900s, several vaccines were developed against tularemia including the killed "Foshay" vaccine, subunit vaccines comprising F. tularensis protein(s) or lipoproteins(s) in an adjuvant formulation, and the F. tularensis Live Vaccine Strain (LVS); none were licensed in the U.S.A. or European Union. The LVS vaccine retains toxicity in humans and animals-especially mice-but has demonstrated efficacy in humans, and thus serves as the current gold standard for vaccine efficacy studies. The U.S.A. 2001 anthrax bioterrorism attack spawned renewed interest in vaccines against potential biowarfare agents including F. tularensis. Since live attenuated-but not killed or subunit-vaccines have shown promising efficacy and since vaccine efficacy against respiratory challenge with less virulent subspecies holarctica or F. novicida, or against non-respiratory challenge with virulent subsp. tularensis (Type A) does not reliably predict vaccine efficacy against respiratory challenge with virulent subsp. tularensis, the route of transmission and species of greatest concern in a bioterrorist attack, in this review, we focus on live attenuated tularemia vaccine candidates tested against respiratory challenge with virulent Type A strains, including homologous vaccines derived from mutants of subsp. holarctica, F. novicida, and subsp. tularensis, and heterologous vaccines developed using viral or bacterial vectors to express F. tularensis immunoprotective antigens. We compare the virulence and efficacy of these vaccine candidates with that of LVS and discuss factors that can significantly impact the development and evaluation of live attenuated tularemia vaccines. Several vaccines meet what we would consider the minimum criteria for vaccines to go forward into clinical development-safety greater than LVS and efficacy at least as great as LVS, and of these, several meet the higher standard of having efficacy ≥LVS in the demanding mouse model of tularemia. These latter include LVS with deletions in purMCD, sodBFt , capB or wzy; LVS ΔcapB that also overexpresses Type VI Secretion System (T6SS) proteins; FSC200 with a deletion in clpB; the single deletional purMCD mutant of F. tularensis SCHU S4, and a heterologous prime-boost vaccine comprising LVS ΔcapB and Listeria monocytogenes expressing T6SS proteins.
Collapse
Affiliation(s)
- Qingmei Jia
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Marcus A. Horwitz
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
6
|
Deletion of the Major Facilitator Superfamily Transporter fptB Alters Host Cell Interactions and Attenuates Virulence of Type A Francisella tularensis. Infect Immun 2018; 86:IAI.00832-17. [PMID: 29311235 PMCID: PMC5820938 DOI: 10.1128/iai.00832-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/22/2017] [Indexed: 12/12/2022] Open
Abstract
Francisella tularensis is a Gram-negative, facultative, intracellular coccobacillus that can infect a wide variety of hosts. In humans, F. tularensis causes the zoonosis tularemia following insect bites, ingestion, inhalation, and the handling of infected animals. The fact that a very small inoculum delivered by the aerosol route can cause severe disease, coupled with the possibility of its use as an aerosolized bioweapon, has led to the classification of Francisella tularensis as a category A select agent and has renewed interest in the formulation of a vaccine. To this end, we engineered a type A strain SchuS4 derivative containing a targeted deletion of the major facilitator superfamily (MFS) transporter fptB. Based on the attenuating capacity of this deletion in the F. tularensis LVS background, we hypothesized that the deletion of this transporter would alter the intracellular replication and cytokine induction of the type A strain and attenuate virulence in the stringent C57BL/6J mouse model. Here we demonstrate that the deletion of fptB significantly alters the intracellular life cycle of F. tularensis, attenuating intracellular replication in both cell line-derived and primary macrophages and inducing a novel cytosolic escape delay. Additionally, we observed prominent differences in the in vitro cytokine profiles in human macrophage-like cells. The mutant was highly attenuated in the C57BL/6J mouse model and provided partial protection against virulent type A F. tularensis challenge. These results indicate a fundamental necessity for this nutrient transporter in the timely progression of F. tularensis through its replication cycle and in pathogenesis.
Collapse
|
7
|
Freudenberger Catanzaro KC, Champion AE, Mohapatra N, Cecere T, Inzana TJ. Glycosylation of a Capsule-Like Complex (CLC) by Francisella novicida Is Required for Virulence and Partial Protective Immunity in Mice. Front Microbiol 2017; 8:935. [PMID: 28611741 PMCID: PMC5447757 DOI: 10.3389/fmicb.2017.00935] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/09/2017] [Indexed: 01/11/2023] Open
Abstract
Francisella tularensis is a Gram-negative bacterium and the etiologic agent of tularemia. F. tularensis may appear encapsulated when examined by transmission electron microscopy (TEM), which is due to production of an extracellular capsule-like complex (CLC) when the bacterium is grown under specific environmental conditions. Deletion of two glycosylation genes in the live vaccine strain (LVS) results in loss of apparent CLC and attenuation of LVS in mice. In contrast, F. novicida, which is also highly virulent for mice, is reported to be non-encapsulated. However, the F. novicida genome contains a putative polysaccharide locus with homology to the CLC glycosylation locus in F. tularensis. Following daily subculture of F. novicida in Chamberlain's defined medium, an electron dense material surrounding F. novicida, similar to the F. tularensis CLC, was evident. Extraction with urea effectively removed the CLC, and compositional analysis indicated the extract contained galactose, glucose, mannose, and multiple proteins, similar to those found in the F. tularensis CLC. The same glycosylation genes deleted in LVS were targeted for deletion in F. novicida by allelic exchange using the same mutagenesis vector used for mutagenesis of LVS. In contrast, this mutation also resulted in the loss of five additional genes immediately upstream of the targeted mutation (all within the glycosylation locus), resulting in strain F. novicida Δ1212-1218. The subcultured mutant F. novicida Δ1212-1218 was CLC-deficient and the CLC contained significantly less carbohydrate than the subcultured parent strain. The mutant was severely attenuated in BALB/c mice inoculated intranasally, as determined by the lower number of F. novicida Δ1212-1218 recovered in tissues compared to the parent, and by clearance of the mutant by 10-14 days post-challenge. Mice immunized intranasally with F. novicida Δ1212-1218 were partially protected against challenge with the parent, produced significantly reduced levels of inflammatory cytokines, and their spleens contained only areas of lymphoid hyperplasia, whereas control mice challenged with the parent exhibited hypercytokinemia and splenic necrosis. Therefore, F. novicida is capable of producing a CLC similar to that of F. tularensis, and glycosylation of the CLC contributed to F. novicida virulence and immunoprotection.
Collapse
Affiliation(s)
- Kelly C Freudenberger Catanzaro
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Anna E Champion
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Nrusingh Mohapatra
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Thomas Cecere
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States
| | - Thomas J Inzana
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland College of Veterinary Medicine, Virginia TechBlacksburg, VA, United States.,Department of Biomedical Sciences, Virginia Tech Carilion School of MedicineRoanoke, VA, United States
| |
Collapse
|
8
|
Ainsworth S, Ketter PM, Yu JJ, Grimm RC, May HC, Cap AP, Chambers JP, Guentzel MN, Arulanandam BP. Vaccination with a live attenuated Acinetobacter baumannii deficient in thioredoxin provides protection against systemic Acinetobacter infection. Vaccine 2017; 35:3387-3394. [PMID: 28522011 DOI: 10.1016/j.vaccine.2017.05.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/27/2017] [Accepted: 05/05/2017] [Indexed: 01/12/2023]
Abstract
Multi-drug resistant Acinetobacter baumannii (MDR-Ab), an opportunistic pathogen associated with nosocomial and combat related infections, has a high mortality due to its virulence and limited treatment options. Deletion of the thioredoxin gene (TrxA) from a clinical isolate of MDR-Ab resulted in a 100-fold increase in 50% lethal dose (LD50) in a systemic challenge murine model. Thus, we investigated the potential use of this attenuated strain as a live vaccine against MDR-Ab. Mice were vaccinated by subcutaneous (s.c.) injection of 2×105 CFU of the ΔtrxA mutant, boosted 14days later with an equivalent inoculum, and then challenged 30days post-vaccination by i.p. injection with 10 LD50 of the wild type (WT) Ci79 strain. Efficacy of vaccination was evaluated by monitoring MDR-Ab specific antibody titers and cytokine production, observing pathology and organ burdens after WT challenge, and measuring levels of serum pentraxin-3, a molecular correlate of A. baumannii infection severity, before and after challenge. Mice vaccinated with ΔtrxA were fully protected against the lethal challenge of WT. However, minimal immunoglobulin class switching was observed with IgM predominating. Spleens harvested from vaccinated mice exhibited negligible levels of IL-4, IFN-γ and IL-17 production when stimulated with UV-inactivated WT Ci79. Importantly, tissues obtained from vaccinated mice displayed reduced pathology and organ burden compared to challenged non-vaccinated mice. Additionally, serum pentraxin-3 concentrations were not increased 24h after challenge in vaccinated mice, correlating with reduction of WT MDR-Ab infection in ΔtrxA immunized mice. Furthermore, passive immunization with ΔtrxA-immune sera provided protection against lethal systemic Ci79 challenge. Collectively, the defined live attenuated ΔtrxA strain is a vaccine candidate against emerging MDR Acinetobacter infection.
Collapse
Affiliation(s)
- Sarah Ainsworth
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States
| | - Patrick M Ketter
- Coagulation and Blood Research Program, US Army Institute for Surgical Research, JBSA Fort Sam Houston, TX 78234, United States
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States
| | - Rose C Grimm
- Comparative Pathology Division, US Army Institute for Surgical Research, JBSA Fort Sam Houston, TX 78234, United States
| | - Holly C May
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States
| | - Andrew P Cap
- Coagulation and Blood Research Program, US Army Institute for Surgical Research, JBSA Fort Sam Houston, TX 78234, United States
| | - James P Chambers
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States
| | - M Neal Guentzel
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States
| | - Bernard P Arulanandam
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio; San Antonio, TX 78249, United States.
| |
Collapse
|
9
|
Chou AY, Kennett NJ, Melillo AA, Elkins KL. Murine survival of infection with Francisella novicida and protection against secondary challenge is critically dependent on B lymphocytes. Microbes Infect 2016; 19:91-100. [PMID: 27965147 DOI: 10.1016/j.micinf.2016.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 10/13/2016] [Accepted: 12/05/2016] [Indexed: 12/18/2022]
Abstract
Respiratory infection of mice with Francisella novicida has recently been used as a model for the highly virulent human pathogen Francisella tularensis. Similar to F. tularensis, even small doses of F. novicida administered by respiratory routes are lethal for inbred laboratory mice. This feature obviously limits study of infection-induced immunity. Parenteral sublethal infections of mice with F. novicida are feasible, but the resulting immune responses are incompletely characterized. Here we use parenteral intradermal (i.d.) and intraperitoneal (i.p.) F. novicida infections of C57BL/6J mice to determine the role of B cells in controlling primary and secondary F. novicida infections. Despite developing comparable levels of F. novicida-primed T cells, B cell knockout mice were much more susceptible to both primary i.d. infection and secondary i.p. challenge than wild type (normal) C57BL/6J mice. Transfer of F. novicida-immune sera to either wild type C57BL/6J mice or to B cell knockout mice did not appreciably impact survival of subsequent lethal F. novicida challenge. However, F. novicida-immune mice that were depleted of T cells after priming but just before challenge survived and cleared secondary i.p. F. novicida challenge. Collectively these results indicate that B cells, if not serum antibodies, play a major role in controlling F. novicida infections in mice.
Collapse
Affiliation(s)
- Alicia Y Chou
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Nikki J Kennett
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Amanda A Melillo
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Karen L Elkins
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States.
| |
Collapse
|
10
|
Jia Q, Bowen R, Lee BY, Dillon BJ, Masleša-Galić S, Horwitz MA. Francisella tularensis Live Vaccine Strain deficient in capB and overexpressing the fusion protein of IglA, IglB, and IglC from the bfr promoter induces improved protection against F. tularensis respiratory challenge. Vaccine 2016; 34:4969-4978. [PMID: 27577555 DOI: 10.1016/j.vaccine.2016.08.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/18/2016] [Accepted: 08/12/2016] [Indexed: 10/21/2022]
Abstract
A safer and more effective vaccine than the unlicensed Francisella tularensis Live Vaccine Strain (LVS) is needed to protect against the biowarfare agent F. tularensis. Previously, we developed an LVS ΔcapB mutant that is significantly safer than LVS and provides potent protective immunity against F. tularensis respiratory challenge when administered intranasally but limited protection when administered intradermally unless as part of a prime-boost vaccination strategy. To improve the immunogenicity and efficacy of LVS ΔcapB, we developed recombinant LVS ΔcapB (rLVS ΔcapB) strains overexpressing various F. tularensis Francisella Pathogenicity Island (FPI) proteins - IglA, IglB and IglC, and a fusion protein (IglABC) comprising immunodominant epitopes of IglA, IglB, and IglC downstream of different Francisella promoters, including the bacterioferritin (bfr) promoter. We show that rLVS ΔcapB/bfr-iglA, iglB, iglC, and iglABC express more IglA, IglB, IglC or IglABC than parental LVS ΔcapB in broth and in human macrophages, and stably express FPI proteins in macrophages and mice absent antibiotic selection. In response to IglC and heat-inactivated LVS, spleen cells from mice immunized intradermally with rLVS ΔcapB/bfr-iglC or bfr-iglABC secrete greater amounts of interferon-gamma and/or interleukin-17 than those from mice immunized with LVS ΔcapB, comparable to those from LVS-immunized mice. Mice immunized with rLVS ΔcapB/bfr-iglA, iglB, iglC or iglABC produce serum antibodies at levels similar to LVS-immunized mice. Mice immunized intradermally with rLVS ΔcapB/bfr-iglABC and challenged intranasally with virulent F. tularensis Schu S4 survive longer than sham- and LVS ΔcapB-immunized mice. Mice immunized intranasally with rLVS ΔcapB/bfr-iglABC - but not with LVS - just before or after respiratory challenge with F. tularensis Schu S4 are partially protected; protection is correlated with induction of a strong innate immune response. Thus, rLVS ΔcapB/bfr-iglABC shows improved immunogenicity and protective efficacy compared with parental LVS ΔcapB and, in contrast to LVS, has partial efficacy as immediate pre- and post-exposure prophylaxis.
Collapse
Affiliation(s)
- Qingmei Jia
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California - Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1688, United States.
| | - Richard Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, United States.
| | - Bai-Yu Lee
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California - Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1688, United States.
| | - Barbara Jane Dillon
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California - Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1688, United States.
| | - Saša Masleša-Galić
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California - Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1688, United States.
| | - Marcus A Horwitz
- Division of Infectious Diseases, Department of Medicine, 37-121 Center for Health Sciences, School of Medicine, University of California - Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1688, United States.
| |
Collapse
|
11
|
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.
Collapse
|
12
|
Cunningham AL, Guentzel MN, Yu JJ, Hung CY, Forsthuber TG, Navara CS, Yagita H, Williams IR, Klose KE, Eaves-Pyles TD, Arulanandam BP. M-Cells Contribute to the Entry of an Oral Vaccine but Are Not Essential for the Subsequent Induction of Protective Immunity against Francisella tularensis. PLoS One 2016; 11:e0153402. [PMID: 27100824 PMCID: PMC4839702 DOI: 10.1371/journal.pone.0153402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
M-cells (microfold cells) are thought to be a primary conduit of intestinal antigen trafficking. Using an established neutralizing anti-RANKL (Receptor Activator of NF-κB Ligand) antibody treatment to transiently deplete M-cells in vivo, we sought to determine whether intestinal M-cells were required for the effective induction of protective immunity following oral vaccination with ΔiglB (a defined live attenuated Francisella novicida mutant). M-cell depleted, ΔiglB-vaccinated mice exhibited increased (but not significant) morbidity and mortality following a subsequent homotypic or heterotypic pulmonary F. tularensis challenge. No significant differences in splenic IFN-γ, IL-2, or IL-17 or serum antibody (IgG1, IgG2a, IgA) production were observed compared to non-depleted, ΔiglB-vaccinated animals suggesting complementary mechanisms for ΔiglB entry. Thus, we examined other possible routes of gastrointestinal antigen sampling following oral vaccination and found that ΔiglB co-localized to villus goblet cells and enterocytes. These results provide insight into the role of M-cells and complementary pathways in intestinal antigen trafficking that may be involved in the generation of optimal immunity following oral vaccination.
Collapse
Affiliation(s)
- Aimee L. Cunningham
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - M. Neal Guentzel
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Jieh-Juen Yu
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Chiung-Yu Hung
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Thomas G. Forsthuber
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Christopher S. Navara
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Hideo Yagita
- Department of Immunology, Juntendo University, Tokyo, Japan
| | - Ifor R. Williams
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Karl E. Klose
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Tonyia D. Eaves-Pyles
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Bernard P. Arulanandam
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
13
|
Santiago AE, Mann BJ, Qin A, Cunningham AL, Cole LE, Grassel C, Vogel SN, Levine MM, Barry EM. Characterization of Francisella tularensis Schu S4 defined mutants as live-attenuated vaccine candidates. Pathog Dis 2015; 73:ftv036. [PMID: 25986219 PMCID: PMC4462183 DOI: 10.1093/femspd/ftv036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2015] [Indexed: 01/11/2023] Open
Abstract
Francisella tularensis (Ft), the etiological agent of tularemia and a Tier 1 select agent, has been previously weaponized and remains a high priority for vaccine development. Ft tularensis (type A) and Ft holarctica (type B) cause most human disease. We selected six attenuating genes from the live vaccine strain (LVS; type B), F. novicida and other intracellular bacteria: FTT0507, FTT0584, FTT0742, FTT1019c (guaA), FTT1043 (mip) and FTT1317c (guaB) and created unmarked deletion mutants of each in the highly human virulent Ft strain Schu S4 (Type A) background. FTT0507, FTT0584, FTT0742 and FTT1043 Schu S4 mutants were not attenuated for virulence in vitro or in vivo. In contrast, Schu S4 gua mutants were unable to replicate in murine macrophages and were attenuated in vivo, with an i.n. LD50 > 105 CFU in C57BL/6 mice. However, the gua mutants failed to protect mice against lethal challenge with WT Schu S4, despite demonstrating partial protection in rabbits in a previous study. These results contrast with the highly protective capacity of LVS gua mutants against a lethal LVS challenge in mice, and underscore differences between these strains and the animal models in which they are evaluated, and therefore have important implications for vaccine development. Mutations in guanine biosynthesis genes, but not in four other hypothetical virulence factors in highly virulent Francisella tularensis strain Schu S4 resulted in attenuation in macrophage replication and mouse virulence.
Collapse
Affiliation(s)
- Araceli E Santiago
- Departments of Pediatrics, University of Virginia Children's Hospital, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Barbara J Mann
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Aiping Qin
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Aimee L Cunningham
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Leah E Cole
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Christen Grassel
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Stefanie N Vogel
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Eileen M Barry
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| |
Collapse
|
14
|
Law HT, Sriram A, Fevang C, Nix EB, Nano FE, Guttman JA. IglC and PdpA are important for promoting Francisella invasion and intracellular growth in epithelial cells. PLoS One 2014; 9:e104881. [PMID: 25115488 PMCID: PMC4130613 DOI: 10.1371/journal.pone.0104881] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 07/17/2014] [Indexed: 01/06/2023] Open
Abstract
The highly infectious bacteria, Francisella tularensis, colonize a variety of organs and replicate within both phagocytic as well as non-phagocytic cells, to cause the disease tularemia. These microbes contain a conserved cluster of important virulence genes referred to as the Francisella Pathogenicity Island (FPI). Two of the most characterized FPI genes, iglC and pdpA, play a central role in bacterial survival and proliferation within phagocytes, but do not influence bacterial internalization. Yet, their involvement in non-phagocytic epithelial cell infections remains unexplored. To examine the functions of IglC and PdpA on bacterial invasion and replication during epithelial cell infections, we infected liver and lung epithelial cells with F. novicida and F. tularensis 'Type B' Live Vaccine Strain (LVS) deletion mutants (ΔiglC and ΔpdpA) as well as their respective gene complements. We found that deletion of either gene significantly reduced their ability to invade and replicate in epithelial cells. Gene complementation of iglC and pdpA partially rescued bacterial invasion and intracellular growth. Additionally, substantial LAMP1-association with both deletion mutants was observed up to 12 h suggesting that the absence of IglC and PdpA caused deficiencies in their ability to dissociate from LAMP1-positive Francisella Containing Vacuoles (FCVs). This work provides the first evidence that IglC and PdpA are important pathogenic factors for invasion and intracellular growth of Francisella in epithelial cells, and further highlights the discrete mechanisms involved in Francisella infections between phagocytic and non-phagocytic cells.
Collapse
Affiliation(s)
- H. T. Law
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Aarati Sriram
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Charlotte Fevang
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Eli B. Nix
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Francis E. Nano
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Julian Andrew Guttman
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| |
Collapse
|
15
|
Cunningham AL, Dang KM, Yu JJ, Guentzel MN, Heidner HW, Klose KE, Arulanandam BP. Enhancement of vaccine efficacy by expression of a TLR5 ligand in the defined live attenuated Francisella tularensis subsp. novicida strain U112ΔiglB::fljB. Vaccine 2014; 32:5234-40. [PMID: 25050972 DOI: 10.1016/j.vaccine.2014.07.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 06/11/2014] [Accepted: 07/09/2014] [Indexed: 01/13/2023]
Abstract
Oral vaccination with the defined live attenuated Francisella novicida vaccine strain U112ΔiglB has been demonstrated to induce protective immunity against pulmonary challenge with the highly human virulent Francisella tularensis strain SCHU S4. However, this vaccination regimen requires a booster dose in mice and Exhibits 50% protective efficacy in the Fischer 344 rat model. To enhance the efficacy of this vaccine strain, we engineered U112ΔiglB to express the Salmonella typhimurium FljB flagellin D1 domain, a TLR5 agonist. The U112ΔiglB::fljB strain was highly attenuated for intracellular macrophage replication, and although the FljB protein was expressed within the cytosol, it exhibited TLR5 activation in a TLR5-expressing HEK cell line. Additionally, infection of splenocytes and lymphocytes with U112ΔiglB::fljB induced significantly greater TNF-α production than infection with U112ΔiglB. Oral vaccination with U112ΔiglB::fljB also induced significantly greater protection than U112ΔiglB against pulmonary SCHU S4 challenge in rats. The enhanced protection was accompanied by higher IgG2a production and serum-mediated reduction of Francisella infectivity. Thus, the U112ΔiglB::fljB strain may serve as a potential vaccine candidate against pneumonic tularemia.
Collapse
Affiliation(s)
- Aimee L Cunningham
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States; Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, United States
| | - Kim Minh Dang
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - M Neal Guentzel
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Hans W Heidner
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Karl E Klose
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Bernard P Arulanandam
- South Texas Center for Emerging Infectious Disease and the Center for Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, TX 78249, United States.
| |
Collapse
|
16
|
Kingry LC, Petersen JM. Comparative review of Francisella tularensis and Francisella novicida. Front Cell Infect Microbiol 2014; 4:35. [PMID: 24660164 PMCID: PMC3952080 DOI: 10.3389/fcimb.2014.00035] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 02/22/2014] [Indexed: 01/08/2023] Open
Abstract
Francisella tularensis is the causative agent of the acute disease tularemia. Due to its extreme infectivity and ability to cause disease upon inhalation, F. tularensis has been classified as a biothreat agent. Two subspecies of F. tularensis, tularensis and holarctica, are responsible for tularemia in humans. In comparison, the closely related species F. novicida very rarely causes human illness and cases that do occur are associated with patients who are immune compromised or have other underlying health problems. Virulence between F. tularensis and F. novicida also differs in laboratory animals. Despite this varying capacity to cause disease, the two species share ~97% nucleotide identity, with F. novicida commonly used as a laboratory surrogate for F. tularensis. As the F. novicida U112 strain is exempt from U.S. select agent regulations, research studies can be carried out in non-registered laboratories lacking specialized containment facilities required for work with virulent F. tularensis strains. This review is designed to highlight phenotypic (clinical, ecological, virulence, and pathogenic) and genomic differences between F. tularensis and F. novicida that warrant maintaining F. novicida and F. tularensis as separate species. Standardized nomenclature for F. novicida is critical for accurate interpretation of experimental results, limiting clinical confusion between F. novicida and F. tularensis and ensuring treatment efficacy studies utilize virulent F. tularensis strains.
Collapse
Affiliation(s)
- Luke C Kingry
- Division of Vector-Borne Diseases, Bacterial Diseases Branch, Centers for Disease Control and Prevention Fort Collins, CO, USA
| | - Jeannine M Petersen
- Division of Vector-Borne Diseases, Bacterial Diseases Branch, Centers for Disease Control and Prevention Fort Collins, CO, USA
| |
Collapse
|
17
|
Chou AY, Kennett NJ, Nix EB, Schmerk CL, Nano FE, Elkins KL. Generation of protection against Francisella novicida in mice depends on the pathogenicity protein PdpA, but not PdpC or PdpD. Microbes Infect 2013; 15:816-27. [PMID: 23880085 DOI: 10.1016/j.micinf.2013.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/11/2013] [Accepted: 07/15/2013] [Indexed: 01/24/2023]
Abstract
Previous results suggest that mutations in most genes in the Francisella pathogenicity island (FPI) attenuate the bacterium. Using a mouse model, here we determined the impact of mutations in pdpA, pdpC, and pdpD in Francisella novicida on in vitro replication in macrophages, and in vivo immunogenicity. In contrast to most FPI genes, deletion of pdpC (FnΔpdpC) and pdpD (FnΔpdpD) from F. novicida did not impact growth in mouse bone-marrow derived macrophages. Nonetheless, both FnΔpdpC and FnΔpdpD were highly attenuated when administered intradermally. Infected mice produced relatively normal anti-F. novicida serum antibodies. Further, splenocytes from infected mice controlled intramacrophage Francisella replication, indicating T cell priming, and mice immunized by infection with FnΔpdpC or FnΔpdpD survived secondary lethal parenteral challenge with either F. novicida or Francisella tularensis LVS. In contrast, deletion of pdpA (FnΔpdpA) ablated growth in macrophages in vitro. FnΔpdpA disseminated and replicated poorly in infected mice, accompanied by development of some anti-F. novicida serum antibodies. However, primed Th1 cells were not detected, and vaccinated mice did not survive even low dose challenge with either F. novicida or LVS. Taken together, these results suggest that successful priming of Th1 cells, and protection against lethal challenge, depends on expression of PdpA.
Collapse
Affiliation(s)
- Alicia Y Chou
- Laboratory of Mycobacterial Diseases and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 1401 Rockville Pike, HFM-431, Rockville, MD 20852, USA
| | | | | | | | | | | |
Collapse
|
18
|
Production of outer membrane vesicles and outer membrane tubes by Francisella novicida. J Bacteriol 2012; 195:1120-32. [PMID: 23264574 DOI: 10.1128/jb.02007-12] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella spp. are highly infectious and virulent bacteria that cause the zoonotic disease tularemia. Knowledge is lacking for the virulence factors expressed by Francisella and how these factors are secreted and delivered to host cells. Gram-negative bacteria constitutively release outer membrane vesicles (OMV), which may function in the delivery of virulence factors to host cells. We identified growth conditions under which Francisella novicida produces abundant OMV. Purification of the vesicles revealed the presence of tube-shaped vesicles in addition to typical spherical OMV, and examination of whole bacteria revealed the presence of tubes extending out from the bacterial surface. Recently, both prokaryotic and eukaryotic cells have been shown to produce membrane-enclosed projections, termed nanotubes, which appear to function in cell-cell communication and the exchange of molecules. In contrast to these previously characterized structures, the F. novicida tubes are produced in liquid as well as on solid medium and are derived from the OM rather than the cytoplasmic membrane. The production of the OMV and tubes (OMV/T) by F. novicida was coordinately regulated and responsive to both growth medium and growth phase. Proteomic analysis of purified OMV/T identified known Francisella virulence factors among the constituent proteins, suggesting roles for the vesicles in pathogenesis. In support of this, production of OM tubes by F. novicida was stimulated during infection of macrophages and addition of purified OMV/T to macrophages elicited increased release of proinflammatory cytokines. Finally, vaccination with purified OMV/T protected mice from subsequent challenge with highly lethal doses of F. novicida.
Collapse
|
19
|
Signarovitz AL, Ray HJ, Yu JJ, Guentzel MN, Chambers JP, Klose KE, Arulanandam BP. Mucosal immunization with live attenuated Francisella novicida U112ΔiglB protects against pulmonary F. tularensis SCHU S4 in the Fischer 344 rat model. PLoS One 2012; 7:e47639. [PMID: 23118885 PMCID: PMC3484155 DOI: 10.1371/journal.pone.0047639] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 09/18/2012] [Indexed: 12/17/2022] Open
Abstract
The need for an efficacious vaccine against Francisella tularensis is a consequence of its low infectious dose and high mortality rate if left untreated. This study sought to characterize a live attenuated subspecies novicida-based vaccine strain (U112ΔiglB) in an established second rodent model of pulmonary tularemia, namely the Fischer 344 rat using two distinct routes of vaccination (intratracheal [i.t.] and oral). Attenuation was verified by comparing replication of U112ΔiglB with wild type parental strain U112 in F344 primary alveolar macrophages. U112ΔiglB exhibited an LD50>107 CFU compared to the wild type (LD50 = 5×106 CFU i.t.). Immunization with 107 CFU U112ΔiglB by i.t. and oral routes induced antigen-specific IFN-γ and potent humoral responses both systemically (IgG2a>IgG1 in serum) and at the site of mucosal vaccination (respiratory/intestinal compartment). Importantly, vaccination with U112ΔiglB by either i.t. or oral routes provided equivalent levels of protection (50% survival) in F344 rats against a subsequent pulmonary challenge with ∼25 LD50 (1.25×104 CFU) of the highly human virulent strain SCHU S4. Collectively, these results provide further evidence on the utility of a mucosal vaccination platform with a defined subsp. novicida U112ΔiglB vaccine strain in conferring protective immunity against pulmonary tularemia.
Collapse
Affiliation(s)
- Aimee L. Signarovitz
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Heather J. Ray
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - M. N. Guentzel
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - James P. Chambers
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Bernard P. Arulanandam
- South Texas Center for Emerging Infectious Disease and Center of Excellence in Infection Genomics, University of Texas at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
20
|
Arulanandam BP, Chetty SL, Yu JJ, Leonard S, Klose K, Seshu J, Cap A, Valdes JJ, Chambers JP. Francisella DnaK inhibits tissue-nonspecific alkaline phosphatase. J Biol Chem 2012; 287:37185-94. [PMID: 22923614 DOI: 10.1074/jbc.m112.404400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Following pulmonary infection with Francisella tularensis, we observed an unexpected but significant reduction of alkaline phosphatase, an enzyme normally up-regulated following inflammation. However, no reduction was observed in mice infected with a closely related gram-negative pneumonic organism (Klebsiella pneumoniae) suggesting the inhibition may be Francisella-specific. In similar fashion to in vivo observations, addition of Francisella lysate to exogenous alkaline phosphatase (tissue-nonspecific isozyme) was inhibitory. Partial purification and subsequent proteomic analysis indicated the inhibitory factor to be the heat shock protein DnaK. Incubation with increasing amounts of anti-DnaK antibody reduced the inhibitory effect in a dose-dependent manner. Furthermore, DnaK contains an adenosine triphosphate binding domain at its N terminus, and addition of adenosine triphosphate enhances dissociation of DnaK with its target protein, e.g. alkaline phosphatase. Addition of adenosine triphosphate resulted in decreased DnaK co-immunoprecipitated with alkaline phosphatase as well as reduction of Francisella-mediated alkaline phosphatase inhibition further supporting the binding of Francisella DnaK to alkaline phosphatase. Release of DnaK via secretion and/or bacterial cell lysis into the extracellular milieu and inhibition of plasma alkaline phosphatase could promote an orchestrated, inflammatory response advantageous to Francisella.
Collapse
|
21
|
Perforin- and granzyme-mediated cytotoxic effector functions are essential for protection against Francisella tularensis following vaccination by the defined F. tularensis subsp. novicida ΔfopC vaccine strain. Infect Immun 2012; 80:2177-85. [PMID: 22493083 DOI: 10.1128/iai.00036-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A licensed vaccine against Francisella tularensis is currently not available. Two Francisella tularensis subsp. novicida (herein referred to by its earlier name, Francisella novicida) attenuated strains, the ΔiglB and ΔfopC strains, have previously been evaluated as potential vaccine candidates against pneumonic tularemia in experimental animals. F. novicida ΔiglB, a Francisella pathogenicity island (FPI) mutant, is deficient in phagosomal escape and intracellular growth, whereas F. novicida ΔfopC, lacking the outer membrane lipoprotein FopC, which is required for evasion of gamma interferon (IFN-γ)-mediated signaling, is able to escape and replicate in the cytosol. To dissect the difference in protective immune mechanisms conferred by these two vaccine strains, we examined the efficacy of the F. novicida ΔiglB and ΔfopC mutants against pulmonary live-vaccine-strain (LVS) challenge and found that both strains provided comparable protection in wild-type, major histocompatibility complex class I (MHC I) knockout, and MHC II knockout mice. However, F. novicida ΔfopC-vaccinated but not F. novicida ΔiglB-vaccinated perforin-deficient mice were more susceptible and exhibited greater bacterial burdens than similarly vaccinated wild-type mice. Moreover, perforin produced by natural killer (NK) cells and release of granzyme contributed to inhibition of LVS replication within macrophages. This NK cell-mediated LVS inhibition was enhanced with anti-F. novicida ΔfopC immune serum, suggesting antibody-dependent cell-mediated cytotoxicity (ADCC) in F. novicida ΔfopC-mediated protection. Overall, this study provides additional immunological insight into the basis for protection conferred by live attenuated F. novicida strains with different phenotypes and supports further investigation of this organism as a vaccine platform for tularemia.
Collapse
|
22
|
Straskova A, Cerveny L, Spidlova P, Dankova V, Belcic D, Santic M, Stulik J. Deletion of IglH in virulent Francisella tularensis subsp. holarctica FSC200 strain results in attenuation and provides protection against the challenge with the parental strain. Microbes Infect 2012; 14:177-87. [DOI: 10.1016/j.micinf.2011.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 08/18/2011] [Accepted: 08/30/2011] [Indexed: 12/24/2022]
|
23
|
Conlan JW. Tularemia vaccines: recent developments and remaining hurdles. Future Microbiol 2011; 6:391-405. [PMID: 21526941 DOI: 10.2217/fmb.11.22] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Francisella tularensis subsp. tularensis is a facultative intracellular bacterial pathogen of humans and other mammals. Its inhaled infectious dose is very low and can result in very high mortality. Historically, subsp. tularensis was developed as a biological weapon and there are now concerns about its abuse as such by terrorists. A live attenuated vaccine developed pragmatically more than half a century ago from the less virulent holarctica subsp. is the sole prophylactic available, but it remains unlicensed. In recent years several other potential live, killed and subunit vaccine candidates have been developed and tested in mice for their efficacy against respiratory challenge with subsp. tularensis. This article will review these vaccine candidates and the development hurdles they face.
Collapse
Affiliation(s)
- J Wayne Conlan
- National Research Council, Institute for Biological Sciences, Ottawa, Ontario, Canada.
| |
Collapse
|
24
|
Kim TH, Pinkham JT, Heninger SJ, Chalabaev S, Kasper DL. Genetic modification of the O-polysaccharide of Francisella tularensis results in an avirulent live attenuated vaccine. J Infect Dis 2011; 205:1056-65. [PMID: 21969334 DOI: 10.1093/infdis/jir620] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Francisella tularensis, the causative agent of tularemia, is a highly virulent microbe. One significant virulence factor of F. tularensis is the O-polysaccharide (O-PS) portion of the organism's lipopolysaccharide. METHODS A wzy (O-antigen polymerase) deletion mutant of Ft. live attenuated vaccine strain (Ft.LVS), designated Ft.LVS::Δwzy, was created and evaluated as a live attenuated vaccine. Specifically, the mutant's virulence potential and its protective efficacy against type A and type B strains were investigated by challenge of immunized mice. RESULTS F. tularensis LVS::Δwzy expressed only 1 repeating unit of O-PS and yet, upon immunization, induced O-PS-specific antibodies. Compared with Ft.LVS, the mutant was highly sensitive to complement-mediated lysis, significantly attenuated in virulence, and was recovered in much lower numbers from the organs of infected mice. Intranasal immunization with Ft.LVS::Δwzy provided protection against subsequent intranasal infection with the highly virulent type A strain SchuS4 and with Ft.LVS. Immunization with Ft.LVS::Δwzy elicited both humoral and cell-mediated immunity. CONCLUSIONS Ft.LVS::Δwzy was avirulent in mice and, despite expressing only 1 repeating unit of the O-PS, induced antibodies to the full-length O-PS. Vaccination with Ft.LVS::Δwzy protected mice against intranasal challenge with both type A and type B strains of F. tularensis and induced functional immunity through both humoral and cellular mechanisms.
Collapse
Affiliation(s)
- Tae-Hyun Kim
- Department of Microbiology and Molecular Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | | | |
Collapse
|
25
|
Macrophage replication screen identifies a novel Francisella hydroperoxide resistance protein involved in virulence. PLoS One 2011; 6:e24201. [PMID: 21915295 PMCID: PMC3167825 DOI: 10.1371/journal.pone.0024201] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 08/02/2011] [Indexed: 11/25/2022] Open
Abstract
Francisella tularensis is a Gram-negative facultative intracellular pathogen and the causative agent of tularemia. Recently, genome-wide screens have identified Francisella genes required for virulence in mice. However, the mechanisms by which most of the corresponding proteins contribute to pathogenesis are still largely unknown. To further elucidate the roles of these virulence determinants in Francisella pathogenesis, we tested whether each gene was required for replication of the model pathogen F. novicida within macrophages, an important virulence trait. Fifty-three of the 224 genes tested were involved in intracellular replication, including many of those within the Francisella pathogenicity island (FPI), validating our results. Interestingly, over one third of the genes identified are annotated as hypothetical, indicating that F. novicida likely utilizes novel virulence factors for intracellular replication. To further characterize these virulence determinants, we selected two hypothetical genes to study in more detail. As predicted by our screen, deletion mutants of FTN_0096 and FTN_1133 were attenuated for replication in macrophages. The mutants displayed differing levels of attenuation in vivo, with the FTN_1133 mutant being the most attenuated. FTN_1133 has sequence similarity to the organic hydroperoxide resistance protein Ohr, an enzyme involved in the bacterial response to oxidative stress. We show that FTN_1133 is required for F. novicida resistance to, and degradation of, organic hydroperoxides as well as resistance to the action of the NADPH oxidase both in macrophages and mice. Furthermore, we demonstrate that F. holarctica LVS, a strain derived from a highly virulent human pathogenic species of Francisella, also requires this protein for organic hydroperoxide resistance as well as replication in macrophages and mice. This study expands our knowledge of Francisella's largely uncharacterized intracellular lifecycle and demonstrates that FTN_1133 is an important novel mediator of oxidative stress resistance.
Collapse
|
26
|
Conlan JW, Chen W, Bosio CM, Cowley SC, Elkins KL. Infection of mice with Francisella as an immunological model. CURRENT PROTOCOLS IN IMMUNOLOGY 2011; Chapter 19:Unit 19.14. [PMID: 21462168 PMCID: PMC3405980 DOI: 10.1002/0471142735.im1914s93] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This unit describes the utility of various mouse models of infection for studying pathogenesis and adaptive immune responses to the facultative intracellular bacteria pathogen Francisella tularensis. By judicious use of different combinations of mouse and bacterial strains, as well as different routes of infection, murine tularemia models may be used to explore a complete picture of F. tularensis infection and immunity. Moreover, studies using Francisella, particularly the Live Vaccine Strain (LVS), serve as a convenient and tractable model system that appears to be representative of mammalian host responses to intracellular pathogens in general.
Collapse
Affiliation(s)
- J Wayne Conlan
- National Research Council of Canada, Institute for Biological Sciences, Ottawa, Ontario, Canada
| | | | | | | | | |
Collapse
|
27
|
Nallaparaju KC, Yu JJ, Rodriguez SA, Zogaj X, Manam S, Guentzel MN, Seshu J, Murthy AK, Chambers JP, Klose KE, Arulanandam BP. Evasion of IFN-γ signaling by Francisella novicida is dependent upon Francisella outer membrane protein C. PLoS One 2011; 6:e18201. [PMID: 21483828 PMCID: PMC3069069 DOI: 10.1371/journal.pone.0018201] [Citation(s) in RCA: 19] [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: 11/18/2010] [Accepted: 02/24/2011] [Indexed: 12/12/2022] Open
Abstract
Background Francisella tularensis is a Gram-negative facultative intracellular bacterium and the causative agent of the lethal disease tularemia. An outer membrane protein (FTT0918) of F. tularensis subsp. tularensis has been identified as a virulence factor. We generated a F. novicida (F. tularensis subsp. novicida) FTN_0444 (homolog of FTT0918) fopC mutant to study the virulence-associated mechanism(s) of FTT0918. Methods and Findings The ΔfopC strain phenotype was characterized using immunological and biochemical assays. Attenuated virulence via the pulmonary route in wildtype C57BL/6 and BALB/c mice, as well as in knockout (KO) mice, including MHC I, MHC II, and µmT (B cell deficient), but not in IFN-γ or IFN-γR KO mice was observed. Primary bone marrow derived macrophages (BMDM) prepared from C57BL/6 mice treated with rIFN-γ exhibited greater inhibition of intracellular ΔfopC than wildtype U112 strain replication; whereas, IFN-γR KO macrophages showed no IFN-γ-dependent inhibition of ΔfopC replication. Moreover, phosphorylation of STAT1 was downregulated by the wildtype strain, but not the fopC mutant, in rIFN-γ treated macrophages. Addition of NG-monomethyl-L-arginine, an NOS inhibitor, led to an increase of ΔfopC replication to that seen in the BMDM unstimulated with rIFN-γ. Enzymatic screening of ΔfopC revealed aberrant acid phosphatase activity and localization. Furthermore, a greater abundance of different proteins in the culture supernatants of ΔfopC than that in the wildtype U112 strain was observed. Conclusions F. novicida FopC protein facilitates evasion of IFN-γ-mediated immune defense(s) by down-regulation of STAT1 phosphorylation and nitric oxide production, thereby promoting virulence. Additionally, the FopC protein also may play a role in maintaining outer membrane stability (integrity) facilitating the activity and localization of acid phosphatases and other F. novicida cell components.
Collapse
Affiliation(s)
- Kalyan C. Nallaparaju
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Jieh-Juen Yu
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Stephen A. Rodriguez
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Xhavit Zogaj
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Srikanth Manam
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - M. Neal Guentzel
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Janakiram Seshu
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Ashlesh K. Murthy
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - James P. Chambers
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Bernard P. Arulanandam
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
28
|
Pierson T, Matrakas D, Taylor YU, Manyam G, Morozov VN, Zhou W, van Hoek ML. Proteomic Characterization and Functional Analysis of Outer Membrane Vesicles of Francisella novicida Suggests Possible Role in Virulence and Use as a Vaccine. J Proteome Res 2011; 10:954-67. [DOI: 10.1021/pr1009756] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tony Pierson
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Demetrios Matrakas
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Yuka U. Taylor
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
| | - Ganiraju Manyam
- Department of Bioinformatics & Computational Biology, The UT MD Anderson Cancer Center, Houston, Texas, United States
| | - Victor N. Morozov
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, United States
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Weidong Zhou
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia 20110, United States
| | - Monique L. van Hoek
- Department of Molecular and Microbiology, George Mason University, Manassas, Virginia 20110, United States
- National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110, United States
| |
Collapse
|
29
|
Valentino MD, Maben ZJ, Hensley LL, Woolard MD, Kawula TH, Frelinger JA, Frelinger JG. Identification of T-cell epitopes in Francisella tularensis using an ordered protein array of serological targets. Immunology 2011; 132:348-60. [PMID: 21214540 DOI: 10.1111/j.1365-2567.2010.03387.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Francisella tularensis is a Gram-negative intracellular bacterium that is the causative agent of tularaemia. Concerns regarding its use as a bioterrorism agent have led to a renewed interest in the biology of infection, host response and pathogenesis. A robust T-cell response is critical to confer protection against F. tularensis. However, characterization of the cellular immune response has been hindered by the paucity of tools to examine the anti-Francisella immune response at the molecular level. We set out to combine recent advances of genomics with solid-phase antigen delivery coupled with a T-cell functional assay to identify T-cell epitopes. A subset of clones, encoding serological targets, was selected from an F. tularensis SchuS4 ordered genomic library and subcloned into a bacterial expression vector to test the feasibility of this approach. Proteins were expressed and purified individually employing the BioRobot 3000 in a semi-automated purification method. The purified proteins were coupled to beads, delivered to antigen-presenting cells for processing, and screened with Francisella-specific T-cell hybridomas of unknown specificity. We identified cellular reactivity against the pathogenicity protein IglB, and the chaperone proteins GroEL and DnaK. Further analyses using genetic deletions and synthetic peptides were performed to identify the minimal peptide epitopes. Priming with the peptide epitopes before infection with F. tularensis LVS increased the frequency of antigen-specific CD4 T cells as assessed by intracellular interferon-γ staining. These results illustrate the feasibility of screening an arrayed protein library that should be applicable to a variety of pathogens.
Collapse
Affiliation(s)
- Michael D Valentino
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
| | | | | | | | | | | | | |
Collapse
|
30
|
A Francisella tularensis live vaccine strain (LVS) mutant with a deletion in capB, encoding a putative capsular biosynthesis protein, is significantly more attenuated than LVS yet induces potent protective immunity in mice against F. tularensis challenge. Infect Immun 2010; 78:4341-55. [PMID: 20643859 DOI: 10.1128/iai.00192-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is in the top category (category A) of potential agents of bioterrorism. The F. tularensis live vaccine strain (LVS) is the only vaccine currently available to protect against tularemia; however, this unlicensed vaccine is relatively toxic and provides incomplete protection against aerosolized F. tularensis, the most dangerous mode of transmission. Hence, a safer and more potent vaccine is needed. As a first step toward addressing this need, we have constructed and characterized an attenuated version of LVS, LVS ΔcapB, both as a safer vaccine and as a vector for the expression of recombinant F. tularensis proteins. LVS ΔcapB, with a targeted deletion in a putative capsule synthesis gene (capB), is antibiotic resistance marker free. LVS ΔcapB retains the immunoprotective O antigen, is serum resistant, and is outgrown by parental LVS in human macrophage-like THP-1 cells in a competition assay. LVS ΔcapB is significantly attenuated in mice; the 50% lethal dose (LD(50)) intranasally (i.n.) is >10,000-fold that of LVS. Providing CapB in trans to LVS ΔcapB partially restores its virulence in mice. Mice immunized with LVS ΔcapB i.n. or intradermally (i.d.) developed humoral and cellular immune responses comparable to those of mice immunized with LVS, and when challenged 4 or 8 weeks later with a lethal dose of LVS i.n., they were 100% protected from illness and death and had significantly lower levels (3 to 5 logs) of LVS in the lung, liver, and spleen than sham-immunized mice. Most importantly, mice immunized with LVS ΔcapB i.n. or i.d. and then challenged 6 weeks later by aerosol with 10× the LD(50) of the highly virulent type A F. tularensis strain SchuS4 were significantly protected (100% survival after i.n. immunization). These results show that LVS ΔcapB is significantly safer than LVS and yet provides potent protective immunity against virulent F. tularensis SchuS4 challenge.
Collapse
|
31
|
Soto E, Wiles J, Elzer P, Macaluso K, Hawke JP. Attenuated Francisella asiatica iglC mutant induces protective immunity to francisellosis in tilapia. Vaccine 2010; 29:593-8. [PMID: 20600508 DOI: 10.1016/j.vaccine.2010.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/15/2010] [Accepted: 06/10/2010] [Indexed: 11/18/2022]
Abstract
Francisella asiatica is a Gram-negative, facultative intracellular bacteria that causes fish francisellosis. Fish francisellosis is a severe sub-acute to chronic granulomatous disease with high mortalities and high infectivity rates in cultured and wild fish. To date, there is no approved vaccine for this widespread emergent disease. The goal of this study was to characterize the efficacy of a defined F. asiatica mutant (ΔiglC) as a live attenuated vaccine against subsequent immersion challenge with the wild-type (WT) organism. In previous work, the ΔiglC was found to be attenuated upon intraperitoneal injection and immersion challenges. In vitro, the ΔiglC exhibited reduced growth in tilapia head-kidney derived macrophages, and was significantly attenuated (p<0.001) as demonstrated by cytopathogenic and apoptosis assays. In this study, the ΔiglC was tested to determine its ability to protect tilapia against challenge with high doses (lethal dose 80) of WT bacteria. Naïve tilapia vaccinated by immersion with a suspension of the ΔiglC and subsequently challenged with WT F. asiatica were protected (90% mean percent survival) from the lethal challenges. F. asiatica-specific antibodies produced in response to immunization with the ΔiglC were subsequently found to protect naïve tilapia against high-dose F. asiatica challenge in passive immunization experiments. Significant protection (p<0.001) was obtained when fish were passively immunized and challenged with 10(4) and 10(5)CFU/fish of WT F. asiatica; but not when challenged with 10(6)CFU/fish. This is the first report of a defined live attenuated strain providing protection against F. asiatica in fish.
Collapse
Affiliation(s)
- Esteban Soto
- Department of Pathobiological Sciences, Louisiana State University (LSU)-School of Veterinary Medicine, Skip Bertman Dr., Baton Rouge, LA 70803, USA
| | | | | | | | | |
Collapse
|
32
|
Ray HJ, Chu P, Wu TH, Lyons CR, Murthy AK, Guentzel MN, Klose KE, Arulanandam BP. The Fischer 344 rat reflects human susceptibility to francisella pulmonary challenge and provides a new platform for virulence and protection studies. PLoS One 2010; 5:e9952. [PMID: 20376351 PMCID: PMC2848594 DOI: 10.1371/journal.pone.0009952] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 03/05/2010] [Indexed: 11/21/2022] Open
Abstract
Background The pathogenesis of Francisella tularensis, the causative agent of tularemia, has been primarily characterized in mice. However, the high degree of sensitivity of mice to bacterial challenge, especially with the human virulent strains of F. tularensis, limits this animal model for screening of defined attenuated vaccine candidates for protection studies. Methods and Findings We analyzed the susceptibility of the Fischer 344 rat to pulmonary (intratracheal) challenge with three different subspecies (subsp) of F. tularensis that reflect different levels of virulence in humans, and characterized the bacterial replication profile in rat bone marrow-derived macrophages (BMDM). In contrast to the mouse, Fischer 344 rats exhibit a broader range of sensitivity to pulmonary challenge with the human virulent subsp. tularensis and holarctica. Unlike mice, Fischer rats exhibited a high degree of resistance to pulmonary challenge with LVS (an attenuated derivative of subsp. holarctica) and subsp. novicida. Within BMDM, subsp. tularensis and LVS showed minimal replication, subsp. novicida showed marginal replication, and subsp. holartica replicated robustly. The limited intramacrophage replication of subsp. tularensis and novicida strains was correlated with the induction of nitric oxide production. Importantly, Fischer 344 rats that survived pulmonary infection with subsp. novicida were markedly protected against subsequent pulmonary challenge with subsp. tularensis, suggesting that subsp. novicida may be a useful platform for the development of vaccines against subsp. tularensis. Conclusions The Fischer 344 rat exhibits similar sensitivity to F. tularensis strains as that reported for humans, and thus the Fischer 344 ray may serve as a better animal model for tularemia vaccine development.
Collapse
Affiliation(s)
- Heather J. Ray
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Ping Chu
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Terry H. Wu
- Center for Infectious Disease and Immunity, Department of Internal Medicine, The University of New Mexico Health Science Center, Albuquerque, New Mexico, United States of America
| | - C. Rick Lyons
- Center for Infectious Disease and Immunity, Department of Internal Medicine, The University of New Mexico Health Science Center, Albuquerque, New Mexico, United States of America
| | - Ashlesh K. Murthy
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - M. Neal Guentzel
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Karl E. Klose
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Bernard P. Arulanandam
- South Texas Center for Emerging Infectious Diseases and Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
| |
Collapse
|
33
|
Francisella tularensis T-cell antigen identification using humanized HLA-DR4 transgenic mice. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 17:215-22. [PMID: 20016043 DOI: 10.1128/cvi.00361-09] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
There is no licensed vaccine against the intracellular pathogen Francisella tularensis. The use of conventional mouse strains to screen protective vaccine antigens may be problematic, given the differences in the major histocompatibility complex (MHC) binding properties between murine and human antigen-presenting cells. We used engineered humanized mice that lack endogenous MHC class II alleles but that express a human HLA allele (HLA-DR4 transgenic [tg] mice) to identify potential subunit vaccine candidates. Specifically, we applied a biochemical and immunological screening approach with bioinformatics to select putative F. tularensis subsp. novicida T-cell-reactive antigens using humanized HLA-DR4 tg mice. Cell wall- and membrane-associated proteins were extracted with Triton X-114 detergent and were separated by fractionation with a Rotofor apparatus and whole-gel elution. A series of proteins were identified from fractions that stimulated antigen-specific gamma interferon (IFN-gamma) production, and these were further downselected by the use of bioinformatics and HLA-DR4 binding algorithms. We further examined the validity of this combinatorial approach with one of the identified proteins, a 19-kDa Francisella tularensis outer membrane protein (designated Francisella outer membrane protein B [FopB]; FTN_0119). FopB was shown to be a T-cell antigen by a specific IFN-gamma recall assay with purified CD4(+) T cells from F. tularensis subsp. novicida DeltaiglC-primed HLA-DR4 tg mice and cells of a human B-cell line expressing HLA-DR4 (DRB1*0401) functioning as antigen-presenting cells. Intranasal immunization of HLA-DR4 tg mice with the single antigen FopB conferred significant protection against lethal pulmonary challenge with an F. tularensis subsp. holarctica live vaccine strain. These results demonstrate the value of combining functional biochemical and immunological screening with humanized HLA-DR4 tg mice to map HLA-DR4-restricted Francisella CD4(+) T-cell epitopes.
Collapse
|
34
|
Pechous RD, McCarthy TR, Zahrt TC. Working toward the future: insights into Francisella tularensis pathogenesis and vaccine development. Microbiol Mol Biol Rev 2009; 73:684-711. [PMID: 19946137 PMCID: PMC2786580 DOI: 10.1128/mmbr.00028-09] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Francisella tularensis is a facultative intracellular gram-negative pathogen and the etiological agent of the zoonotic disease tularemia. Recent advances in the field of Francisella genetics have led to a rapid increase in both the generation and subsequent characterization of mutant strains exhibiting altered growth and/or virulence characteristics within various model systems of infection. In this review, we summarize the major properties of several Francisella species, including F. tularensis and F. novicida, and provide an up-to-date synopsis of the genes necessary for pathogenesis by these organisms and the determinants that are currently being targeted for vaccine development.
Collapse
Affiliation(s)
- Roger D. Pechous
- Center for Biopreparedness and Infectious Disease and Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226-0509
| | - Travis R. McCarthy
- Center for Biopreparedness and Infectious Disease and Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226-0509
| | - Thomas C. Zahrt
- Center for Biopreparedness and Infectious Disease and Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226-0509
| |
Collapse
|