scholarly journals Protective Immunity against Tularemia Provided by an Adenovirus-Vectored Vaccine Expressing Tul4 of Francisella tularensis

2012 ◽  
Vol 19 (3) ◽  
pp. 359-364 ◽  
Author(s):  
Ravinder Kaur ◽  
Shan Chen ◽  
Maria T. Arévalo ◽  
Qingfu Xu ◽  
Yanping Chen ◽  
...  
Keyword(s):  
Single Dose ◽  
Francisella Tularensis ◽  
Virulent Strain ◽  
Lethal Dose ◽  
Protein Vaccine ◽  
Lethal Challenge ◽  
Live Attenuated Vaccine ◽  
Content Type ◽  
Skin Contact ◽  
Vectored Vaccine

ABSTRACTFrancisella tularensis, a category A bioterrorism agent, is a highly infectious organism that is passed on via skin contact and inhalation routes. A live attenuated vaccine strain (LVS) has been developed, but it has not been licensed for public use by the FDA due to safety concerns. Thus, there exists a need for a safer and improved vaccine. In this study, we have constructed a replication-incompetent adenovirus, Ad/opt-Tul4, carrying a codon-optimized gene for expression of a membrane protein, Tul4, ofF. tularensisLVS. Its ability to protect against lethal challenge and its immunogenicity were evaluated in a murine model. An intramuscular injection of a single dose (1 × 107PFU) of Ad/opt-Tul4 elicited a robust Tul4-specific antibody response. Assays suggest a Th1-driven response. A single dose elicited 20% protection against challenge with 100 × 50% lethal dose (LD50)F. tularensisLVS; two additional booster shots resulted in 60% protection. In comparison, three doses of 5 μg recombinant Tul4 protein did not elicit significant protection against challenge. Therefore, the Ad/opt-Tul4 vaccine was more effective than the protein vaccine, and protection was dose dependent. Compared to LVS, the protection rate is lower, but an adenovirus-vectored vaccine may be more attractive due to its enhanced safety profile and mucosal route of delivery. Furthermore, simple genetic modification of the vaccine may potentially produce antibodies protective against a fully virulent strain ofF. tularensis. Our data support the development and further research of an adenovirus-vectored vaccine against Tul4 ofF. tularensisLVS.

scholarly journals Liposome Encapsulation of Ciprofloxacin Improves Protection against Highly Virulent Francisella tularensis Strain Schu S4

2014 ◽  
Vol 58 (6) ◽  
pp. 3053-3059 ◽  
Author(s):  
Karleigh A. Hamblin ◽  
Stuart J. Armstrong ◽  
Kay B. Barnes ◽  
Carwyn Davies ◽  
Jonathan P. Wong ◽  
...  
Keyword(s):  
Single Dose ◽  
Francisella Tularensis ◽  
Infection Model ◽  
Prophylactic Regimen ◽  
Lethal Challenge ◽  
Content Type ◽  
Deliberate Release ◽  
Oral Ciprofloxacin ◽  
Schu S4 ◽  
Full Protection

ABSTRACTLiposome-encapsulated ciprofloxacin for inhalation (CFI) was investigated as a putative postexposure therapeutic for two strains ofFrancisella tularensis. The efficacies of oral ciprofloxacin and intranasally instilled CFI could not be distinguished in a mouse model of infection with theF. tularensislive vaccine strain (LVS), where a single dose of either formulation offered full protection against a lethal challenge. However, mouse studies with the more virulent Schu S4 strain ofF. tularensisdemonstrated that a higher level of protection against a lethal aerosol infection is provided by CFI than by oral ciprofloxacin. In addition, using this infection model, it was possible to discriminate the efficacy of intranasally instilled CFI from that of aerosolized CFI, with aerosolized CFI providing full protection after just a single dose. The improved efficacy of CFI compared to oral ciprofloxacin is likely due to the high sustained concentrations of ciprofloxacin in the lung. In summary, CFI may be a promising therapy, perhaps enabling the prophylactic regimen to be shortened, for use in the event of a deliberate release ofF. tularensis. The prophylactic efficacy of CFI against other biological warfare (BW) threat agents also warrants investigation.

scholarly journals Needle-Free Delivery of Acetalated Dextran-Encapsulated AR-12 Protects Mice from Francisella tularensis Lethal Challenge

2016 ◽  
Vol 60 (4) ◽  
pp. 2052-2062 ◽  
Author(s):  
Ky V. Hoang ◽  
Heather Curry ◽  
Michael A. Collier ◽  
Hassan Borteh ◽  
Eric M. Bachelder ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Lethal Challenge ◽  
Content Type ◽  
Human Macrophages ◽  
Gentamicin Treatment ◽  
Significant Toxicity ◽  
Serovar Typhimurium ◽  
Spectrum Activity

ABSTRACTFrancisella tularensiscauses tularemia and is a potential biothreat. Given the limited antibiotics for treating tularemia and the possible use of antibiotic-resistant strains as a biowarfare agent, new antibacterial agents are needed. AR-12 is an FDA-approved investigational new drug (IND) compound that induces autophagy and has shown host-directed, broad-spectrum activityin vitroagainstSalmonella entericaserovar Typhimurium andF. tularensis. We have shown that AR-12 encapsulated within acetalated dextran (Ace-DEX) microparticles (AR-12/MPs) significantly reduces host cell cytotoxicity compared to that with free AR-12, while retaining the ability to controlS.Typhimurium within infected human macrophages. In the present study, the toxicity and efficacy of AR-12/MPs in controlling virulent type AF. tularensisSchuS4 infection were examinedin vitroandin vivo. No significant toxicity of blank MPs or AR-12/MPs was observed in lung histology sections when the formulations were given intranasally to uninfected mice. In histology sections from the lungs of intranasally infected mice treated with the formulations, increased macrophage infiltration was observed for AR-12/MPs, with or without suboptimal gentamicin treatment, but not for blank MPs, soluble AR-12, or suboptimal gentamicin alone. AR-12/MPs dramatically reduced the burden ofF. tularensisin infected human macrophages, in a manner similar to that of free AR-12. However,in vivo, AR-12/MPs significantly enhanced the survival ofF. tularensisSchuS4-infected mice compared to that seen with free AR-12. In combination with suboptimal gentamicin treatment, AR-12/MPs further improved the survival ofF. tularensisSchuS4-infected mice. These studies provide support for Ace-DEX-encapsulated AR-12 as a promising new therapeutic agent for tularemia.

scholarly journals A Single Dose of Modified Vaccinia Ankara Expressing Lassa Virus-like Particles Protects Mice from Lethal Intra-cerebral Virus Challenge

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 133 ◽  
Author(s):  
Maria S. Salvato ◽  
Arban Domi ◽  
Camila Guzmán-Cardozo ◽  
Sandra Medina-Moreno ◽  
Juan Carlos Zapata ◽  
...  
Keyword(s):  
Single Dose ◽  
Matrix Protein ◽  
Lethal Dose ◽  
Health Impact ◽  
Lassa Virus ◽  
Protein Z ◽  
Glycoprotein Precursor ◽  
Lethal Challenge ◽  
Virus Like Particles ◽  
Virus Challenge

Lassa fever surpasses Ebola, Marburg, and all other hemorrhagic fevers except Dengue in its public health impact. Caused by Lassa virus (LASV), the disease is a scourge on populations in endemic areas of West Africa, where reported incidence is higher. Here, we report construction, characterization, and preclinical efficacy of a novel recombinant vaccine candidate GEO-LM01. Constructed in the Modified Vaccinia Ankara (MVA) vector, GEO-LM01 expresses the glycoprotein precursor (GPC) and zinc-binding matrix protein (Z) from the prototype Josiah strain lineage IV. When expressed together, GP and Z form Virus-Like Particles (VLPs) in cell culture. Immunogenicity and efficacy of GEO-LM01 was tested in a mouse challenge model. A single intramuscular dose of GEO-LM01 protected 100% of CBA/J mice challenged with a lethal dose of ML29, a Mopeia/Lassa reassortant virus, delivered directly into the brain. In contrast, all control animals died within one week. The vaccine induced low levels of antibodies but Lassa-specific CD4+ and CD8+ T cell responses. This is the first report showing that a single dose of a replication-deficient MVA vector can confer full protection against a lethal challenge with ML29 virus.

scholarly journals The Live Attenuated Actinobacillus pleuropneumoniae Triple-Deletion Mutant ΔapxICΔapxIICΔapxIV-ORF1Strain, SLW05, Immunizes Pigs against Lethal Challenge with Haemophilus parasuis

2012 ◽  
Vol 20 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Shulin Fu ◽  
Jiwen Ou ◽  
Minmin Zhang ◽  
Juan Xu ◽  
Huazhen Liu ◽  
...  
Keyword(s):  
Deletion Mutant ◽  
Lethal Dose ◽  
Interleukin 2 ◽  
Actinobacillus Pleuropneumoniae ◽  
Economic Losses ◽  
Respiratory Pathogens ◽  
Haemophilus Parasuis ◽  
Lethal Challenge ◽  
Content Type ◽  
Novel Approach

ABSTRACTHaemophilus parasuisandActinobacillus pleuropneumoniaeboth belong to the familyPasteurellaceaeand are major respiratory pathogens that cause large economic losses in the pig industry worldwide. We previously constructed an attenuatedA. pleuropneumoniaeserovar 1 live vaccine prototype, SLW05 (ΔapxICΔapxIICΔapxIV-ORF1), which is able to produce nontoxic but immunogenic ApxIA, ApxIIA, and ApxIVA. This triple-deletion mutant strain was shown to elicit protective immunity against virulentA. pleuropneumoniae. In the present study, we investigated whether immunization with SLW05 could also protect against lethal challenge with virulentH. parasuisSH0165 (serovar 5) or MD0322 (serovar 4). The SLW05 strain was found to elicit a strong humoral antibody response in pigs and to confer significant protection against challenge with a lethal dose ofH. parasuisSH0165 or MD0322. IgG subtype analysis revealed that SLW05 induces a bias toward a Th1-type immune response and stimulates interleukin 2 (IL-2) and gamma interferon (IFN-γ) production. Moreover, antisera from SLW05-vaccinated pigs efficiently inhibited bothA. pleuropneumoniaeandH. parasuisgrowth in a whole-blood assay. This is the first report that a live attenuatedA. pleuropneumoniaevaccine with SLW05 can protect against lethalH. parasuisinfection, which provides a novel approach for developing an attenuatedH. parasuisvaccine.

scholarly journals Engineering and Preclinical Evaluation of Attenuated Nontyphoidal Salmonella Strains Serving as Live Oral Vaccines and as Reagent Strains

2011 ◽  
Vol 79 (10) ◽  
pp. 4175-4185 ◽  
Author(s):  
Sharon M. Tennant ◽  
Jin-Yuan Wang ◽  
James E. Galen ◽  
Raphael Simon ◽  
Marcela F. Pasetti ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lethal Dose ◽  
Invasive Disease ◽  
Oral Immunization ◽  
Oral Vaccines ◽  
Wild Type ◽  
Lethal Challenge ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTWhile nontyphoidalSalmonella(NTS) has long been recognized as a cause of self-limited gastroenteritis, it is becoming increasingly evident that multiple-antibiotic-resistant strains are also emerging as important causes of invasive bacteremia and focal infections, resulting in hospitalizations and deaths. We have constructed attenuatedSalmonella entericaserovar Typhimurium andSalmonella entericaserovar Enteritidis strains that can serve as live oral vaccines and as “reagent strains” for subunit vaccine production in a safe and economical manner. Prototype attenuated vaccine strains CVD 1921 and CVD 1941, derived from the invasive wild-type strainsS. TyphimuriumI77 andS. EnteritidisR11, respectively, were constructed by deletingguaBA, encoding guanine biosynthesis, andclpP, encoding a master protease regulator. TheclpPmutation resulted in a hyperflagellation phenotype. An additional deletion infliDyielded reagent strains CVD 1923 and CVD 1943, respectively, which export flagellin monomers. Oral 50% lethal dose (LD50) analyses showed that the NTS vaccine strains were all highly attenuated in mice. Oral immunization with CVD 1921 or CVD 1923 protected mice against lethal challenge with wild-typeS. TyphimuriumI77. Immunization with CVD 1941 but not CVD 1943 protected mice against lethal infection withS. EnteritidisR11. Immune responses induced by these strains included high levels of serum IgG anti-lipopolysaccharide (LPS) and anti-flagellum antibodies, with titers increasing progressively during the immunization schedule. SinceS. TyphimuriumandS. Enteritidisare the most common NTS serovars associated with invasive disease, these findings can pave the way for development of a highly effective, broad-spectrum vaccine against invasive NTS.

scholarly journals Francisella tularensis Schu S4 Lipopolysaccharide Core Sugar and O-Antigen Mutants Are Attenuated in a Mouse Model of Tularemia

2014 ◽  
Vol 82 (4) ◽  
pp. 1523-1539 ◽  
Author(s):  
Jed A. Rasmussen ◽  
Deborah M. B. Post ◽  
Bradford W. Gibson ◽  
Stephen R. Lindemann ◽  
Michael A. Apicella ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Francisella Tularensis ◽  
Lethal Dose ◽  
Protective Effects ◽  
Wild Type ◽  
Content Type ◽  
O Antigen ◽  
Capsule Production ◽  
Mutant Strains ◽  
Schu S4

ABSTRACTThe virulence factors mediatingFrancisellapathogenesis are being investigated, with an emphasis on understanding how the organism evades innate immunity mechanisms.Francisella tularensisproduces a lipopolysaccharide (LPS) that is essentially inert and a polysaccharide capsule that helps the organism to evade detection by components of innate immunity. Using anF. tularensisSchu S4 mutant library, we identified strains that are disrupted for capsule and O-antigen production. These serum-sensitive strains lack both capsule production and O-antigen laddering. Analysis of the predicted protein sequences for the disrupted genes (FTT1236andFTT1238c) revealed similarity to those forwaa(rfa) biosynthetic genes in other bacteria. Mass spectrometry further revealed that these proteins are involved in LPS core sugar biosynthesis and the ligation of O antigen to the LPS core sugars. The 50% lethal dose (LD50) values of these strains are increased 100- to 1,000-fold for mice. Histopathology revealed that the immune response to theF. tularensismutant strains was significantly different from that observed with wild-type-infected mice. The lung tissue from mutant-infected mice had widespread necrotic debris, but the spleens lacked necrosis and displayed neutrophilia. In contrast, the lungs of wild-type-infected mice had nominal necrosis, but the spleens had widespread necrosis. These data indicate that murine death caused by wild-type strains occurs by a mechanism different from that by which the mutant strains kill mice. Mice immunized with these mutant strains displayed >10-fold protective effects against virulent type AF. tularensischallenge.

scholarly journals Characterization of leptospiral proteins that afford partial protection in hamsters against lethal challenge with Leptospira interrogans

2010 ◽  
Vol 59 (9) ◽  
pp. 1005-1015 ◽  
Author(s):  
Marina V. Atzingen ◽  
Amane P. Gonçales ◽  
Zenaide M. de Morais ◽  
Eduardo R. Araújo ◽  
Thales De Brito ◽  
...  
Keyword(s):  
Virulent Strain ◽  
Lethal Dose ◽  
Whole Genome Sequence ◽  
Leptospira Interrogans ◽  
Lethal Challenge ◽  
T Helper 2 ◽  
Bioinformatic Tools ◽  
Genes Encoding ◽  
Antibody Titres

Leptospirosis is a worldwide zoonosis caused by pathogenic Leptospira. The whole-genome sequence of Leptospira interrogans serovar Copenhageni together with bioinformatic tools allow us to search for novel antigen candidates suitable for improved vaccines against leptospirosis. This study focused on three genes encoding conserved hypothetical proteins predicted to be exported to the outer membrane. The genes were amplified by PCR from six predominant pathogenic serovars in Brazil. The genes were cloned and expressed in Escherichia coli strain BL21-SI using the expression vector pDEST17. The recombinant proteins tagged with N-terminal 6×His were purified by metal-charged chromatography. The proteins were recognized by antibodies present in sera from hamsters that were experimentally infected. Immunization of hamsters followed by challenge with a lethal dose of a virulent strain of Leptospira showed that the recombinant protein rLIC12730 afforded statistically significant protection to animals (44 %), followed by rLIC10494 (40 %) and rLIC12922 (30 %). Immunization with these proteins produced an increase in antibody titres during subsequent boosters, suggesting the involvement of a T-helper 2 response. Although more studies are needed, these data suggest that rLIC12730 and rLIC10494 are promising candidates for a multivalent vaccine for the prevention of leptospirosis.

scholarly journals Pathogenicity of Yersinia pestis Synthesis of 1-Dephosphorylated Lipid A

2013 ◽  
Vol 81 (4) ◽  
pp. 1172-1185 ◽  
Author(s):  
Wei Sun ◽  
David A. Six ◽  
C. Michael Reynolds ◽  
Hak Suk Chung ◽  
Christian R. H. Raetz ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Yersinia Pestis ◽  
Francisella Tularensis ◽  
Inflammatory Reaction ◽  
Lipid A ◽  
Lethal Dose ◽  
Wild Type ◽  
Content Type ◽  
Significant Attenuation

ABSTRACTSynthesis ofEscherichia coliLpxL, which transfers a secondary laurate chain to the 2′ position of lipid A, inYersinia pestisproduced bisphosphoryl hexa-acylated lipid A at 37°C, leading to significant attenuation of virulence. Our previous observations also indicated that strain χ10015(pCD1Ap) (ΔlpxP32::PlpxLlpxL) stimulated a strong inflammatory reaction but sickened mice before recovery and retained virulence via intranasal (i.n.) infection. The development of live, attenuatedY. pestisvaccines may be facilitated by detoxification of its lipopolysaccharide (LPS). Heterologous expression of the lipid A 1-phosphatase, LpxE, fromFrancisella tularensisinY. pestisyields predominantly 1-dephosphorylated lipid A, as confirmed by mass spectrometry. Results indicated that expression of LpxE on top of LpxL provided no significant reduction in virulence ofY. pestisin mice when it was administered i.n. but actually reduced the 50% lethal dose (LD50) by 3 orders of magnitude when the strain was administered subcutaneously (s.c.). Additionally, LpxE synthesis in wild-typeY. pestisKIM6+(pCD1Ap) led to slight attenuation by s.c. inoculation but no virulence change by i.n. inoculation in mice. In contrast toSalmonella enterica, expression of LpxE does not attenuate the virulence ofY. pestis.

scholarly journals A single dose of a vesicular stomatitis virus-based influenza vaccine confers rapid protection against H5 viruses from different clades

npj Vaccines ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Wakako Furuyama ◽  
Pierce Reynolds ◽  
Elaine Haddock ◽  
Kimberly Meade-White ◽  
Mai Quynh Le ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Single Dose ◽  
Vesicular Stomatitis Virus ◽  
Severe Disease ◽  
Lethal Dose ◽  
H5n1 Influenza Virus ◽  
Lethal Challenge ◽  
H5n1 Influenza ◽  
Vesicular Stomatitis ◽  
Fast Acting

AbstractThe avian influenza virus outbreak in 1997 highlighted the potential of the highly pathogenic H5N1 virus to cause severe disease in humans. Therefore, effective vaccines against H5N1 viruses are needed to counter the potential threat of a global pandemic. We have previously developed a fast-acting and efficacious vaccine against Ebola virus (EBOV) using the vesicular stomatitis virus (VSV) platform. In this study, we generated recombinant VSV-based H5N1 influenza virus vectors to demonstrate the feasibility of this platform for a fast-acting pan-H5 influenza virus vaccine. We chose multiple approaches regarding antigen design and genome location to define a more optimized vaccine approach. After the VSV-based H5N1 influenza virus constructs were recovered and characterized in vitro, mice were vaccinated by a single dose or prime/boost regimen followed by challenge with a lethal dose of the homologous H5 clade 1 virus. We found that a single dose of VSV vectors expressing full-length hemagglutinin (HAfl) were sufficient to provide 100% protection. The vaccine vectors were fast-acting as demonstrated by uniform protection when administered 3 days prior to lethal challenge. Moreover, single vaccination induced cross-protective H5-specific antibodies and protected mice against lethal challenge with various H5 clade 2 viruses, highlighting the potential of the VSV-based HAfl as a pan-H5 influenza virus emergency vaccine.

scholarly journals Identification of Mechanisms for Attenuation of the FSC043 Mutant of Francisella tularensis SCHU S4

2014 ◽  
Vol 82 (9) ◽  
pp. 3622-3635 ◽  
Author(s):  
Marie Lindgren ◽  
Linda Tancred ◽  
Igor Golovliov ◽  
Wayne Conlan ◽  
Susan M. Twine ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Virulent Strain ◽  
Small Subset ◽  
Intracellular Replication ◽  
Content Type ◽  
Infected Cells ◽  
Essential Contribution ◽  
Respiratory Challenge ◽  
Schu S4 ◽  
Highly Virulent

ABSTRACTPreviously, we identified a spontaneous, essentially avirulent mutant, FSC043, of the highly virulent strain SCHU S4 ofFrancisella tularensissubsp.tularensis. We have now characterized the phenotype of the mutant and the mechanisms of its attenuation in more detail. Genetic and proteomic analyses revealed that thepdpEgene and most of thepdpCgene were very markedly downregulated and, as previously demonstrated, that the strain expressed partially deleted and fusedfupAandfupBgenes. FSC043 showed minimal intracellular replication and induced no cell cytotoxicity. The mutant showed delayed phagosomal escape; at 18 h, colocalization with LAMP-1 was 80%, indicating phagosomal localization, whereas the corresponding percentages for SCHU S4 and the ΔfupAmutant were <10%. However, a small subset of the FSC043-infected cells contained up to 100 bacteria with LAMP-1 colocalization of around 30%. The unusual intracellular phenotype was similar to that of the ΔpdpCand ΔpdpCΔpdpEmutants. Complementation of FSC043 with the intactfupAandfupBgenes did not affect the phenotype, whereas complementation with thepdpCandpdpEgenes restored intracellular replication and led to marked virulence. Even higher virulence was observed after complementation with both double-gene constructs. After immunization with the FSC043 strain, moderate protection against respiratory challenge with the SCHU S4 strain was observed. In summary, FSC043 showed a highly unusual intracellular phenotype, and based on our findings, we hypothesize that the mutation in thepdpCgene makes an essential contribution to the phenotype.

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