scholarly journals T-bet Regulates Immunity to Francisella tularensis Live Vaccine Strain Infection, Particularly in Lungs

2014 ◽  
Vol 82 (4) ◽  
pp. 1477-1490 ◽  
Author(s):  
Amanda A. Melillo ◽  
Oded Foreman ◽  
Catharine M. Bosio ◽  
Karen L. Elkins
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Interleukin 17 ◽  
Live Vaccine Strain ◽  
Respiratory Protection ◽  
Necrosis Factor Alpha ◽  
Secondary Challenge ◽  
Ifn Γ

ABSTRACTUpregulation of the transcription factor T-bet is correlated with the strength of protection against secondary challenge with the live vaccine strain (LVS) ofFrancisella tularensis. Thus, to determine if this mediator had direct consequences in immunity to LVS, we examined its role in infection. Despite substantialin vivogamma interferon (IFN-γ) levels, T-bet-knockout (KO) mice infected intradermally (i.d.) or intranasally (i.n.) with LVS succumbed to infection with doses 2 log units less than those required for their wild-type (WT) counterparts, and exhibited significantly increased bacterial burdens in the lung and spleen. Lungs of LVS-infected T-bet-KO mice contained fewer lymphocytes and more neutrophils and interleukin-17 than WT mice. LVS-vaccinated T-bet-KO mice survived lethal LVS intraperitoneal secondary challenge but not high doses of LVS i.n. challenge, independently of the route of vaccination. Immune T lymphocytes from the spleens of i.d. LVS-vaccinated WT or KO mice controlled intracellular bacterial replication in anin vitrococulture system, but cultures with T-bet-KO splenocyte supernatants contained less IFN-γ and increased amounts of tumor necrosis factor alpha. In contrast, immune T-bet-KO lung lymphocytes were greatly impaired in controlling intramacrophage growth of LVS; this functional defect is the likely mechanism underpinning the lack of respiratory protection. Taken together, T-bet is important in host resistance to primary LVS infection and i.n. secondary challenge. Thus, T-bet represents a true, useful correlate for immunity to LVS.

scholarly journals Interleukin-17 Protects against the Francisella tularensis Live Vaccine Strain but Not against a Virulent F. tularensis Type A Strain

2013 ◽  
Vol 81 (9) ◽  
pp. 3099-3105 ◽  
Author(s):  
Jerod A. Skyberg ◽  
MaryClare F. Rollins ◽  
Joshua W. Samuel ◽  
Marjorie D. Sutherland ◽  
John T. Belisle ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Type A ◽  
Live Vaccine ◽  
Interleukin 17 ◽  
Live Vaccine Strain ◽  
Wild Type ◽  
Content Type ◽  
Protein Levels ◽  
Ifn Γ

ABSTRACTFrancisella tularensisis a highly infectious intracellular bacterium that causes the zoonotic infection tularemia. While much literature exists on the host response toF. tularensisinfection, the vast majority of work has been conducted using attenuated strains ofFrancisellathat do not cause disease in humans. However, emerging data indicate that the protective immune response against attenuatedF. tularensisversusF. tularensistype A differs. Several groups have recently reported that interleukin-17 (IL-17) confers protection against the live vaccine strain (LVS) ofFrancisella. While we too have found that IL-17Rα−/−mice are more susceptible toF. tularensisLVS infection, our studies, using a virulent type A strain ofF. tularensis(SchuS4), indicate that IL-17Rα−/−mice display organ burdens and pulmonary gamma interferon (IFN-γ) responses similar to those of wild-type mice following infection. In addition, oral LVS vaccination conferred equivalent protection against pulmonary challenge with SchuS4 in both IL-17Rα−/−and wild-type mice. While IFN-γ was found to be critically important for survival in a convalescent model of SchuS4 infection, IL-17 neutralization from either wild-type or IFN-γ−/−mice had no effect on morbidity or mortality in this model. IL-17 protein levels were also higher in the lungs of mice infected with the LVS rather thanF. tularensistype A, while IL-23p19 mRNA expression was found to be caspase-1 dependent in macrophages infected with LVS but not SchuS4. Collectively, these results demonstrate that IL-17 is dispensable for host immunity to type AF. tularensisinfection, and that induced and protective immunity differs between attenuated and virulent strains ofF. tularensis.

scholarly journals Intranasal Interleukin-12 Treatment for Protection against Respiratory Infection with the Francisella tularensis Live Vaccine Strain

2005 ◽  
Vol 73 (4) ◽  
pp. 2306-2311 ◽  
Author(s):  
Nathalie S. Duckett ◽  
Sofia Olmos ◽  
Douglas M. Durrant ◽  
Dennis W. Metzger
Keyword(s):  
Respiratory Infection ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Interleukin 12 ◽  
Live Vaccine Strain ◽  
Wild Type ◽  
Intranasal Infection ◽  
Ifn Γ

ABSTRACT Francisella tularensis is a gram-negative intracellular bacterium that can induce lethal respiratory infection in humans and rodents. However, little is known about the role of innate or adaptive immunity in protection from respiratory tularemia. In the present study, the role of interleukin-12 (IL-12) in inducing protective immunity in the lungs against intranasal infection of mice with the live vaccine strain (LVS) of F. tularensis was investigated. It was found that gamma interferon (IFN-γ) and IL-12 were strictly required for protection, since mice deficient in IFN-γ, IL-12 p35, or IL-12 p40 all succumbed to LVS doses that were sublethal for wild-type mice. Furthermore, exogenous IL-12 treatment 24 h before intranasal infection with a lethal dose of LVS (10,000 CFU) significantly decreased bacterial loads in the lungs, livers, and spleens of wild-type BALB/c and C57BL/6 mice and allowed the animals to survive infection; such protection was not observed in IFN-γ-deficient mice. The resistance induced by IL-12 to LVS infection was still observed in NK cell-deficient beige mice but not in CD8−/− mice. These results demonstrate that exogenous IL-12 delivered intranasally can prevent respiratory tularemia through a mechanism that is at least partially dependent upon the expression of IFN-γ and CD8 T cells.

scholarly journals Diverse Myeloid and Lymphoid Cell Subpopulations Produce Gamma Interferon during Early Innate Immune Responses to Francisella tularensis Live Vaccine Strain

2008 ◽  
Vol 76 (9) ◽  
pp. 4311-4321 ◽  
Author(s):  
Roberto De Pascalis ◽  
Betsy C. Taylor ◽  
Karen L. Elkins
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Nk Cells ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Innate Immune ◽  
Live Vaccine Strain ◽  
Ifn Γ ◽  
Cell Subpopulations

ABSTRACT Francisella tularensis, a small gram-negative intracellular bacterium responsible for causing tularemia, is highly pathogenic and classified as a category A agent of bioterrorism. As for other intracellular pathogens, successful protective immune responses to Francisella tularensis require rapid and efficient induction of gamma interferon (IFN-γ) production. Studies using intracellular bacteria such as Listeria monocytogenes as well as Francisella suggest that natural killer (NK) and T cells are important sources of IFN-γ. However, comprehensive characterization of specific sources of IFN-γ produced during Francisella infection in vivo remains incomplete, and depletion of NK cells before infection of mice with the F. tularensis live vaccine strain (LVS) has little impact on the course or outcome of infection. In this study, we determined the cell subpopulations that respond quickly to intradermal F. tularensis LVS infection of mice by producing IFN-γ within hours to a few days. Splenic and liver lymphocytes were obtained from LVS-infected mice and analyzed for IFN-γ mRNA by reverse transcription-PCR, for intracellular cytokine expression by multiparameter flow cytometry, and for ex vivo production of IFN-γ protein by enzyme-linked immunosorbent assay. Cells producing IFN-γ were readily detectable by day 3 after infection, and numbers progressively increased through days 5 to 7. Importantly, the cell types responsible for IFN-γ production were much more varied than expected: these included not only NK cells and T cells, which might be predicted, but also other cells, including dendritic cells (DCs), “NK DCs,” NK T cells, and neutrophils. Most importantly, since RAG-1 knockout mice appeared to exhibit a frequency of IFN-γ-producing cells comparable to that of intact wild-type mice, early IFN-γ production by innate immune cells does not depend on the presence of T or B cells.

scholarly journals Francisella tularensis Live Vaccine Strain Folate Metabolism and Pseudouridine Synthase Gene Mutants Modulate Macrophage Caspase-1 Activation

2012 ◽  
Vol 81 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Tyler K. Ulland ◽  
Ann M. Janowski ◽  
Blake W. Buchan ◽  
Matthew Faron ◽  
Suzanne L. Cassel ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Live Vaccine ◽  
Live Vaccine Strain ◽  
Wild Type ◽  
Content Type ◽  
Pseudouridine Synthase ◽  
Caspase 1

Francisella tularensisis a Gram-negative bacterium and the causative agent of the disease tularemia. Escape ofF. tularensisfrom the phagosome into the cytosol of the macrophage triggers the activation of the AIM2 inflammasome through a mechanism that is not well understood. Activation of the AIM2 inflammasome results in autocatalytic cleavage of caspase-1, resulting in the processing and secretion of interleukin-1β (IL-1β) and IL-18, which play a crucial role in innate immune responses toF. tularensis. We have identified the5-formyltetrahydrofolate cycloligasegene (FTL_0724) as being important forF. tularensislive vaccine strain (LVS) virulence. Infection of micein vivowith aF. tularensisLVSFTL_0724mutant resulted in diminished mortality compared to infection of mice with wild-type LVS. TheFTL_0724mutant also induced increased inflammasome-dependent IL-1β and IL-18 secretion and cytotoxicity in macrophagesin vitro. In contrast, infection of macrophages with aF. tularensisLVSrluD pseudouridine synthase(FTL_0699) mutant resulted in diminished IL-1β and IL-18 secretion from macrophagesin vitrocompared to infection of macrophages with wild-type LVS. In addition, theFTL_0699mutant was not attenuatedin vivo. These findings further illustrate thatF. tularensisLVS possesses numerous genes that influence its ability to activate the inflammasome, which is a key host strategy to control infection with this pathogenin vivo.

scholarly journals Respiratory Francisella tularensis Live Vaccine Strain Infection Induces Th17 Cells and Prostaglandin E2, Which Inhibits Generation of Gamma Interferon-Positive T Cells

2008 ◽  
Vol 76 (6) ◽  
pp. 2651-2659 ◽  
Author(s):  
Matthew D. Woolard ◽  
Lucinda L. Hensley ◽  
Thomas H. Kawula ◽  
Jeffrey A. Frelinger
Keyword(s):  
T Cells ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Th17 Cells ◽  
Live Vaccine ◽  
Prostaglandin E ◽  
Live Vaccine Strain ◽  
Intranasal Inoculation ◽  
Adaptive Immune ◽  
Ifn Γ

ABSTRACT Two key routes of Francisella tularensis infection are through the skin and airway. We wished to understand how the route of inoculation influenced the primary acute adaptive immune response. We show that an intranasal inoculation of the F. tularensis live vaccine strain (LVS) with a 1,000-fold-smaller dose than an intradermal dose results in similar growth kinetics and peak bacterial burdens. In spite of similar bacterial burdens, we demonstrate a difference in the quality, magnitude, and kinetics of the primary acute T-cell response depending on the route of inoculation. Further, we show that prostaglandin E2 secretion in the lung is responsible for the difference in the gamma interferon (IFN-γ) response. Intradermal inoculation led to a large number of IFN-γ+ T cells 7 days after infection in both the spleen and the lung. In contrast, intranasal inoculation induced a lower number of IFN-γ+ T cells in the spleen and lung but an increased number of Th17 cells in the lung. Intranasal infection also led to a significant increase of prostaglandin E2 (PGE2) in the bronchoalveolar lavage fluid. Inhibition of PGE2 production with indomethacin treatment resulted in increased numbers of IFN-γ+ T cells and decreased bacteremia in the lungs of intranasally inoculated mice. This research illuminates critical differences in acute adaptive immune responses between inhalational and dermal infection with F. tularensis LVS mediated by the innate immune system and PGE2.

scholarly journals Increased Susceptibility of IgA-Deficient Mice to Pulmonary Francisella tularensis Live Vaccine Strain Infection

2013 ◽  
Vol 81 (9) ◽  
pp. 3434-3441 ◽  
Author(s):  
Yoichi Furuya ◽  
Girish S. Kirimanjeswara ◽  
Sean Roberts ◽  
Dennis W. Metzger
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Early Time ◽  
Iga Deficiency ◽  
Live Vaccine ◽  
Interleukin 12 ◽  
Live Vaccine Strain ◽  
Content Type ◽  
Ifn Γ ◽  
Increased Susceptibility

ABSTRACTFrancisella tularensis, the causative agent of tularemia, is most deadly in the pneumonic form; therefore, mucosal immunity is an important first line of defense against this pathogen. We have now evaluated the lethality of primaryF. tularensislive vaccine strain (LVS) pulmonary infection in mice that are defective in IgA (IgA−/−mice), the predominant mucosal Ig isotype. The results showed that IgA−/−mice were more susceptible than IgA+/+mice to intranasalF. tularensisLVS infection, despite developing higher levels of LVS-specific total, IgG, and IgM antibodies in the bronchoalveolar lavage specimens following infection. In addition, the absence of IgA resulted in a significant increase in bacterial loads and reduced survival. Interestingly, IgA−/−mice had lower pulmonary gamma interferon (IFN-γ) levels and decreased numbers of IFN-γ-secreting CD4+and CD8+T cells in the lung on day 9 postinfection compared to IgA+/+mice. Furthermore, IgA−/−mice displayed reduced interleukin 12 (IL-12) levels at early time points, and supplementing IgA−/−mice with IL-12 prior to LVS challenge induced IFN-γ production by NK cells and rescued them from mortality. Thus, IgA−/−mice are highly susceptible to primary pulmonary LVS infections not only because of IgA deficiency but also because of reduced IFN-γ responses.

scholarly journals An In Vitro Model System Used To Study Adherence and Invasion of Francisella tularensis Live Vaccine Strain in Nonphagocytic Cells

2007 ◽  
Vol 75 (6) ◽  
pp. 3178-3182 ◽  
Author(s):  
Stephen R. Lindemann ◽  
Molly K. McLendon ◽  
Michael A. Apicella ◽  
Bradley D. Jones
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
In Vitro Model ◽  
Cytochalasin D ◽  
Live Vaccine ◽  
Live Vaccine Strain ◽  
Intracellular Growth ◽  
Phagocytic Cells ◽  
Vitro Model

ABSTRACT In observing Francisella tularensis interactions with nonphagocytic cell lines in vitro, we noted significant adherence, invasion, and intracellular growth of the bacteria within these cells. F. tularensis live vaccine strain invasion of nonprofessional phagocytic cells is inhibited by cytochalasin D and nocodazole, suggesting that both the actin and microtubule cytoskeletons are important for invasion.

scholarly journals Purified Lipopolysaccharide from Francisella tularensis Live Vaccine Strain (LVS) Induces Protective Immunity against LVS Infection That Requires B Cells and Gamma Interferon

2000 ◽  
Vol 68 (4) ◽  
pp. 1988-1996 ◽  
Author(s):  
Valley C. Dreisbach ◽  
Siobhan Cowley ◽  
Karen L. Elkins
Keyword(s):  
B Cells ◽  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Protective Immunity ◽  
Gamma Interferon ◽  
Live Vaccine ◽  
Immunoglobulin M ◽  
Live Vaccine Strain ◽  
Murine Splenocytes ◽  
Ifn Γ

ABSTRACT Previous results have demonstrated that nonspecific protective immunity against lethal Francisella tularensis live vaccine strain (LVS) or Listeria monocytogenes infection can be stimulated either by sublethal infection with bacteria or by treatment with bacterial DNA given 3 days before lethal challenge. Here we characterize the ability of purified lipopolysaccharide (LPS) fromF. tularensis LVS to stimulate similar early protective immunity. Treatment of mice with surprisingly small amounts of LVS LPS resulted in very strong and long-lived protection against lethal LVS challenge within 2 to 3 days. Despite this strong protective response, LPS purified from F. tularensis LVS did not activate murine B cells for proliferation or polyclonal immunoglobulin secretion, nor did it activate murine splenocytes for secretion of interleukin-4 (IL-4), IL-6, IL-12, or gamma interferon (IFN-γ). Immunization of mice with purified LVS LPS induced a weak specific anti-LPS immunoglobulin M (IgM) response and very little IgG; however, infection of mice with LVS bacteria resulted in vigorous IgM and IgG, particularly IgG2a, anti-LPS antibody responses. Studies using various immunodeficient mouse strains, including LPS-hyporesponsive C3H/HeJ mice, μMT− (B-cell-deficient) knockout mice, and IFN-γ-deficient mice, demonstrated that the mechanism of protection does not involve recognition through the Lpsn gene product; nonetheless, protection was dependent on B cells as well as IFN-γ.

scholarly journals Construction and Characterization of an Attenuated Purine Auxotroph in a Francisella tularensis Live Vaccine Strain

2006 ◽  
Vol 74 (8) ◽  
pp. 4452-4461 ◽  
Author(s):  
Roger Pechous ◽  
Jean Celli ◽  
Renee Penoske ◽  
Stanley F. Hayes ◽  
Dara W. Frank ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Vaccine Strain ◽  
Defined Medium ◽  
Live Vaccine ◽  
Live Vaccine Strain ◽  
Lethal Challenge ◽  
Significant Attenuation ◽  
Infected Cells

ABSTRACT Francisella tularensis is a facultative intracellular pathogen and is the etiological agent of tularemia. It is capable of escaping from the phagosome, replicating to high numbers in the cytosol, and inducing apoptosis in macrophages of a variety of hosts. F. tularensis has received significant attention recently due to its potential use as a bioweapon. Currently, there is no licensed vaccine against F. tularensis, although a partially protective live vaccine strain (LVS) that is attenuated in humans but remains fully virulent for mice was previously developed. An F. tularensis LVS mutant deleted in the purMCD purine biosynthetic locus was constructed and partially characterized by using an allelic exchange strategy. The F. tularensis LVS ΔpurMCD mutant was auxotrophic for purines when grown in defined medium and exhibited significant attenuation in virulence when assayed in murine macrophages in vitro or in BALB/c mice. Growth and virulence defects were complemented by the addition of the purine precursor hypoxanthine or by introduction of purMCDN in trans. The F. tularensis LVS ΔpurMCD mutant escaped from the phagosome but failed to replicate in the cytosol or induce apoptotic and cytopathic responses in infected cells. Importantly, mice vaccinated with a low dose of the F. tularensis LVSΔ purMCD mutant were fully protected against subsequent lethal challenge with the LVS parental strain. Collectively, these results suggest that F. tularensis mutants deleted in the purMCD biosynthetic locus exhibit characteristics that may warrant further investigation of their use as potential live vaccine candidates.

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