scholarly journals Vaccine potential of a nonflagellated, virulence-plasmid-cured (fliD–, pSEVΔ) mutant of Salmonella Enteritidis for chickens

2015 ◽  
Vol 63 (3) ◽  
pp. 285-302 ◽  
Author(s):  
Ariel Imre ◽  
Ama Szmolka ◽  
Ferenc Olasz ◽  
Béla Nagy
Keyword(s):  
Salmonella Enteritidis ◽  
Oral Vaccine ◽  
Virulence Plasmid ◽  
Serological Response ◽  
Protective Capacity ◽  
Live Attenuated Vaccine ◽  
Live Oral Vaccine ◽  
Highly Virulent

The aim of these studies was to assess residual virulence and early protective capacity of a negatively markered live attenuated vaccine candidate Salmonella Enteritidis mutant against a highly virulent S. Enteritidis strain using a dayold chicken model. Nonflagellated FliD negative mutants of Salmonella Enteritidis 11 (SE11) with and without the virulence plasmid proved to be sufficiently attenuated (limited invasiveness in vitro/in vivo) without reduced ability to colonise chicken gut. The early protective activity of a nonflagellated, virulence-plasmidcured (fliD–, pSEVΔ) mutant against organ invasion, caecal colonisation and faecal shedding by the highly virulent challenge strain S. Enteritidis 147 NalR proved to be effective and safe. The innate and adaptive immunity was demonstrable during the first four weeks of life, and the serological response was clearly distinguishable from the response induced by the wild parental strain. In conclusion, we provided data for the first time about a virulence-plasmid-cured, nonflagellated mutant of S. Enteritidis to serve as a basis for development of a negatively markered potential live oral vaccine against virulent S. Enteritidis in chicken.

scholarly journals Characterization and Protective Property of Brucella abortuscydCandlooPMutants

2014 ◽  
Vol 21 (11) ◽  
pp. 1573-1580 ◽  
Author(s):  
Quang Lam Truong ◽  
Youngjae Cho ◽  
Abhijit Kashinath Barate ◽  
Suk Kim ◽  
Tae-Wook Hahn
Keyword(s):  
Bovine Brucellosis ◽  
Protein Motif ◽  
Live Attenuated Vaccine ◽  
Content Type ◽  
Degree Of Protection ◽  
Isogenic Mutants ◽  
High Degree ◽  
Highly Virulent

ABSTRACTBrucella abortusreadily multiplies in professional or nonprofessional phagocytesin vitroand is highly virulent in mice. Isogenic mutants ofB. abortusbiovar 1 strain IVKB9007 lacking the ATP/GDP-binding protein motif A (P-loop) (namedlooP; designated here the IVKB9007looP::Tn5mutant) and the ATP-binding/permease protein (cydC; designated here the IVKB9007cydC::Tn5mutant) were identified and characterized by transposon mutagenesis using the mini-Tn5Km2 transposon. Both mutants were found to be virtually incapable of intracellular replication in both murine macrophages (RAW264.7) and the HeLa cell line, and their virulence was significantly impaired in BALB/c mice. Respective complementation of the IVKB9007looP::Tn5and IVKB9007cydC::Tn5mutants restored their ability to survivein vitroandin vivoto a level comparable with that of the wild type. These findings indicate that thecydCandlooPgenes play important roles in the virulence ofB. abortus. In addition, intraperitoneal immunization of mice with a dose of the live IVKB9007looP::Tn5and IVKB9007cydC::Tn5mutants provided a high degree of protection against challenge with pathogenicB. abortusstrain 544. Both mutants should be evaluated further as a live attenuated vaccine against bovine brucellosis for their ability to stimulate a protective immune response.

Comparative Evaluation of In Vitro and In Vivo Assays for the Detection of Avian Infectious Bronchitis Virus as a Contaminant of Live Poultry Vaccines

1998 ◽  
Vol 26 (5) ◽  
pp. 629-634
Author(s):  
Emiliana Falcone ◽  
Edoardo Vignolo ◽  
Livia Di Trani ◽  
Simona Puzelli ◽  
Maria Tollis
Keyword(s):  
Infectious Bronchitis Virus ◽  
Serological Response ◽  
Avian Infectious Bronchitis Virus ◽  
Animal Testing ◽  
Rt Pcr ◽  
Pcr Assay ◽  
In Vivo Test ◽  
Infectious Bronchitis

A reverse transcriptase polymerase chain reaction (RT-PCR) assay specific for identifying avian infectious bronchitis virus (IBV) in poultry vaccines, and the serological response to IBV induced by the inoculation of chicks with a Newcastle disease vaccine spiked with the Massachusetts strain of IBV, were compared for their ability to detect IBV as a contaminant of avian vaccines. The sensitivity of the IBV-RT-PCR assay provided results which were at least equivalent to the biological effect produced by the inoculation of chicks, allowing this assay to be considered a valid alternative to animal testing in the quality control of avian immunologicals. This procedure can easily be adapted to detect a number of contaminants for which the in vivo test still represents the only available method of detection.

In vitro and in vivo pathogenicity of Salmonella enteritidis clinical strains isolated from North America

2011 ◽  
Vol 193 (11) ◽  
pp. 811-821 ◽  
Author(s):  
Devendra H. Shah ◽  
Xiaohui Zhou ◽  
Tarek Addwebi ◽  
Margaret A. Davis ◽  
Douglas R. Call
Keyword(s):  
North America ◽  
Salmonella Enteritidis ◽  
Clinical Strains

scholarly journals Virulent Shigella flexneri subverts the host innate immune response through manipulation of antimicrobial peptide gene expression

2008 ◽  
Vol 205 (5) ◽  
pp. 1121-1132 ◽  
Author(s):  
Brice Sperandio ◽  
Béatrice Regnault ◽  
Jianhua Guo ◽  
Zhi Zhang ◽  
Samuel L. Stanley ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Shigella Flexneri ◽  
Host Cells ◽  
Virulence Plasmid ◽  
Cationic Peptides ◽  
Immunity Genes ◽  
Genes Encoding ◽  
Peptide Gene

Antimicrobial factors are efficient defense components of the innate immunity, playing a crucial role in the intestinal homeostasis and protection against pathogens. In this study, we report that upon infection of polarized human intestinal cells in vitro, virulent Shigella flexneri suppress transcription of several genes encoding antimicrobial cationic peptides, particularly the human β-defensin hBD-3, which we show to be especially active against S. flexneri. This is an example of targeted survival strategy. We also identify the MxiE bacterial regulator, which controls a regulon encompassing a set of virulence plasmid-encoded effectors injected into host cells and regulating innate signaling, as being responsible for this dedicated regulatory process. In vivo, in a model of human intestinal xenotransplant, we confirm at the transcriptional and translational level, the presence of a dedicated MxiE-dependent system allowing S. flexneri to suppress expression of antimicrobial cationic peptides and promoting its deeper progression toward intestinal crypts. We demonstrate that this system is also able to down-regulate additional innate immunity genes, such as the chemokine CCL20 gene, leading to compromised recruitment of dendritic cells to the lamina propria of infected tissues. Thus, S. flexneri has developed a dedicated strategy to weaken the innate immunity to manage its survival and colonization ability in the intestine.

Administration of a live attenuated Salmonella vaccine using an inactivated oil-emulsion vaccine as a vehicle for commercial chicken flocks

2018 ◽  
Vol 58 (7) ◽  
pp. 1316
Author(s):  
P. J. Groves ◽  
T. Harris ◽  
S. M. Sharpe
Keyword(s):  
Serum Antibody ◽  
In Vivo Studies ◽  
Rapid Decline ◽  
Inactivated Vaccine ◽  
Serological Response ◽  
Oil Emulsion ◽  
Commercial Chicken ◽  
Viral Vaccine

Since the finding that inoculating an aroA- deletion live Salmonella Typhimurium vaccine parenterally provides improved and longer-lasting protection against Salmonella colonisation of the laying-hen intestine, this administration route has been adopted by the industry. To make this method practicable and economical, mixing the live bacterial vaccine with an inactivated viral vaccine has become popular. In vitro and in vivo studies were performed designed to assess the effect on the survival of the live salmonellae and the ability to stimulate serum antibody when mixed into oil-emulsion vaccines, compared with more traditional diluents. A rapid decline in viable salmonellae was observed when mixing with an inactivated Riemerella/Pasteurella bacterin. Mixing with an inactivated viral vaccine produced a less severe and more gradual decline in viable salmonellae over time; however, there was a surprising resuscitation of the bacteria 60 min after mixing. Serum antibody 14 days after inoculation of vaccine diluted in a universal diluent rose significantly, compared with sham vaccinated birds. Birds receiving the vaccine diluted in an inactivated vaccine at the time of preparation did not show a significant serological response; however, when given 60 min post-preparation, serum antibody was significantly increased. There appeared to be a correlation of the magnitude of serum antibody produced with the number of viable salmonellae inoculated. The use of the live vaccine incorporated into an inactivated vaccine may give variable results and needs assessment before adoption.

POTENCIAL ANTIBACTERIANO IN VITRO E TOXICOLÓGICO IN VIVO DAS FOLHAS DO JAMBO VERMELHO (Syzygium malaccensis, Myrtaceae) FRENTE A ZEBRAFISH (D. rerio) ADULTO

2021 ◽  
Author(s):  
Fernando E. T. Cunha ◽  
Maria I. C. Ferreira ◽  
Rafael S. Cruz ◽  
Maria J. G. Ferreira ◽  
Clarissa M. Aquino ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Danio Rerio ◽  
Salmonella Enteritidis

Este trabalho reporta o potencial antibacteriano in vitro e toxicológico in vivo das folhas do jambo (Syzygium malaccense) frente a zebrafish (Danio rerio) adulto (ZFa). As folhas de jambo foram submetidas a desidratação (35 ± 2°C) por 24 horas, trituração e posterior extração de metabólitos por decocção, infusão e maceração com água destilada. Os extratos obtidos foram liofilizados e submetidos a análise de atividade antibacteriana in vitro frente a Gram-negativas (Escherichia coli ATCC 25922, Salmonella Enteritidis IAL 1132) e Gram-positivas (Listeria monocytogenes ATCC 19115 e Staphylococcus aureus ATCC 27664), bem como ao potencial toxicológico in vivo frente ao ZFa. O extrato obtido por infusão se mostrou mais promissor, pois apresentou concentração mínima bactericida (CMB) e concentração mínima inibitória (CMI) com maior potencial frente às gram- positivas (CMB - 6,25 e CMI - 6,25 mg/ml), bem como às gram-negativas (CMB - 25,0 e 3,125 e CMI - 3,125 mg/ml). Todos os extratos testados não se mostraram tóxicos frente ao zebrafish adulto e não alteraram o sistema locomotor dos mesmos. Desta forma, conclui-se que o extrato aquoso das folhas do jambo vermelho (Syzygium malaccense) obtido por infusão é seguro e pode ser utilizado como conservante natural com maior ação antibacteriana. Este trabalho nos conduz a novos estudos de isolamento e caracterização de princípios bioativos.

scholarly journals Outer membrane characteristics of Salmonella enteritidis phage type 4 growing in chickens

1993 ◽  
Vol 111 (3) ◽  
pp. 449-454 ◽  
Author(s):  
H. Chart ◽  
D. Conway ◽  
B. Rowe
Keyword(s):  
Outer Membrane ◽  
Salmonella Enteritidis ◽  
Outer Membrane Proteins ◽  
Phage Type ◽  
Virulence Plasmid ◽  
Uptake System ◽  
Ferric Ions ◽  
Phenotypic Characteristics ◽  
A Subunit

SummaryStrains of Salmonella enteritidis belonging to phage type 4 (SE4) were grown in the peritoneal cavities of chickens, and without subculture on laboratory media examined for inducible in vivo phenotypic characteristics. These bacteria expressed three major outer membrane proteins (OMPs) of 33, 35 and 36 kilodaltons (kDa), and iron regulated OMPs of 74, 78 and 81 kDa. Bacteria growing in vivo did not express flagella, or fimbriae with a subunit molecular mass of 14 kDa (14 kDa fimbriae). Two OMPs of 55 and 23 kDa, expressed during culture in nutrient broth, were repressed during growth in chickens. Possession of a 38 MDa ‘mouse virulence’ plasmid did not influence the expression of OMPs, flagella or fimbriae. It was concluded that strains of SE4 growing in chicken tissues, use an enterobactin mediated iron uptake system to obtain ferric ions, do not express flagella or 14 kDa fimbriae and appear not to express novel OMPs involved in survival in vivo.

scholarly journals Influenza B Virus NS1-Truncated Mutants: Live-Attenuated Vaccine Approach

2008 ◽  
Vol 82 (21) ◽  
pp. 10580-10590 ◽  
Author(s):  
Rong Hai ◽  
Luis Martínez-Sobrido ◽  
Kathryn A. Fraser ◽  
Juan Ayllon ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
Reverse Genetics ◽  
Influenza Viruses ◽  
Influenza B Virus ◽  
Influenza B ◽  
Type I ◽  
Live Attenuated Vaccine ◽  
Live Virus ◽  
B Virus

ABSTRACT Type B influenza viruses can cause substantial morbidity and mortality in the population, and vaccination remains by far the best means of protection against infections with these viruses. Here, we report the construction of mutant influenza B viruses for potential use as improved live-virus vaccine candidates. Employing reverse genetics, we altered the NS1 gene, which encodes a type I interferon (IFN) antagonist. The resulting NS1 mutant viruses induced IFN and, as a consequence, were found to be attenuated in vitro and in vivo. The absence of pathogenicity of the NS1 mutants in both BALB/c and C57BL/6 PKR−/− mice was confirmed. We also provide evidence that influenza B virus NS1 mutants induce a self-adjuvanted immune response and confer effective protection against challenge with both homologous and heterologous B virus strains in mice.

scholarly journals Protective Capacity of the Human Anamnestic Antibody Response during Acute Dengue Virus Infection

2016 ◽  
Vol 90 (24) ◽  
pp. 11122-11131 ◽  
Author(s):  
Meihui Xu ◽  
Roland Züst ◽  
Ying Xiu Toh ◽  
Jennifer M. Pfaff ◽  
Kristen M. Kahle ◽  
...  
Keyword(s):  
Virus Infection ◽  
Antibody Response ◽  
Dengue Virus ◽  
Secondary Infection ◽  
Immune Memory ◽  
Protective Capacity ◽  
Dengue Virus Infection ◽  
Immune Correlates

ABSTRACT Half of the world's population is exposed to the risk of dengue virus infection. Although a vaccine for dengue virus is now available in a few countries, its reported overall efficacy of about 60% is not ideal. Protective immune correlates following natural dengue virus infection remain undefined, which makes it difficult to predict the efficacy of new vaccines. In this study, we address the protective capacity of dengue virus-specific antibodies that are produced by plasmablasts a few days after natural secondary infection. Among a panel of 18 dengue virus-reactive human monoclonal antibodies, four groups of antibodies were identified based on their binding properties. While antibodies targeting the fusion loop of the glycoprotein of dengue virus dominated the antibody response, two smaller groups of antibodies bound to previously undescribed epitopes in domain II of the E protein. The latter, largely serotype-cross-reactive antibodies, demonstrated increased stability of binding at pH 5. These antibodies possessed weak to moderate neutralization capacity in vitro but were the most efficacious in promoting the survival of infected mice. Our data suggest that the cross-reactive anamnestic antibody response has a protective capacity despite moderate neutralization in vitro and a moderate decrease of viremia in vivo . IMPORTANCE Antibodies can protect from symptomatic dengue virus infection. However, it is not easy to assess which classes of antibodies provide protection because in vitro assays are not always predictive of in vivo protection. During a repeat infection, dengue virus-specific immune memory cells are reactivated and large amounts of antibodies are produced. By studying antibodies cloned from patients with heterologous secondary infection, we tested the protective value of the serotype-cross-reactive “recall” or “anamnestic” response. We found that results from in vitro neutralization assays did not always correlate with the ability of the antibodies to reduce viremia in a mouse model. In addition, a decrease of viremia in mice did not necessarily improve survival. The most protective antibodies were stable at pH 5, suggesting that antibody binding in the endosomes, after the antibody-virus complex is internalized, might be important to block virus spread in the organism.

scholarly journals Epitope Determinants of a Chimpanzee Dengue Virus Type 4 (DENV-4)-Neutralizing Antibody and Protection against DENV-4 Challenge in Mice and Rhesus Monkeys by Passively Transferred Humanized Antibody

2007 ◽  
Vol 81 (23) ◽  
pp. 12766-12774 ◽  
Author(s):  
Ching-Juh Lai ◽  
Ana P. Goncalvez ◽  
Ruhe Men ◽  
Claire Wernly ◽  
Olivia Donau ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Virus Type ◽  
High Titer ◽  
Neutralizing Antibody ◽  
Denv Infection ◽  
Passive Transfer ◽  
Escape Mutant ◽  
Protective Capacity

ABSTRACT The chimpanzee monoclonal antibody (MAb) 5H2 is specific for dengue virus type 4 (DENV-4) and neutralizes the virus at a high titer in vitro. The epitope detected by the antibody was mapped by sequencing neutralization escape variants of the virus. One variant contained a Lys174-Glu substitution and another contained a Pro176-Leu substitution in domain I of the DENV-4 envelope protein (E). These mutations reduced binding affinity for the antibody 18- to >100-fold. Humanized immunoglobulin G (IgG) 5H2, originally produced from an expression vector, has been shown to be a variant containing a nine-amino-acid deletion in the Fc region which completely ablates antibody-dependent enhancement of DENV replication in vitro. The variant MAb, termed IgG 5H2 ΔD, is particularly attractive for exploring its protective capacity in vivo. Passive transfer of IgG 5H2 ΔD at 20 μg/mouse afforded 50% protection of suckling mice against challenge with 25 50% lethal doses of mouse neurovirulent DENV-4 strain H241. Passive transfer of antibody to monkeys was conducted to demonstrate proof of concept for protection against DENV challenge. Monkeys that received 2 mg/kg of body weight of IgG 5H2 ΔD were completely protected against 100 50% monkey infectious doses (MID50) of DENV-4, as indicated by the absence of viremia and seroconversion. A DENV-4 escape mutant that contained a Lys174-Glu substitution identical to that found in vitro was isolated from monkeys challenged with 106 MID50 of DENV-4. This substitution was also present in all naturally occurring isolates belonging to DENV-4 genotype III. These studies have important implications for possible antibody-mediated prevention of DENV infection.

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