Vaccination and Protection of Pigs against Pleuropneumonia with a Vaccine Strain of Actinobacillus pleuropneumoniaeProduced by Site-Specific Mutagenesis of the ApxII Operon

ABSTRACT The production of toxin (Apx)-neutralizing antibodies during infection plays a major role in the induction of protective immunity toActinobacillus pleuropneumoniae reinfection. In the present study, the gene encoding the ApxII-activating protein,apxIIC, was insertionally inactivated on the chromosome of a serovar 7 strain, HS93. Expression of the structural toxin, ApxIIA, and of the two genes required for its secretion, apxIB andapxID, still occurs in this strain. The resulting mutant strain, HS93C− Ampr, was found to secrete the unactivated toxin. Pigs vaccinated with live HS93C−Ampr via the intranasal route were protected against a cross-serovar challenge with a virulent serovar 1 strain ofA. pleuropneumoniae. This is the first reported vaccine strain of A. pleuropneumoniae which can be delivered live to pigs and offers cross-serovar protection against porcine pleuropneumonia.

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Construction and immunogenicity of a ∆apxIC/ompP2 mutant of Actinobacillus pleuropneumoniae and Haemophilus parasuis

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v80i1.519 ◽

2013 ◽

Vol 80 (1) ◽

Cited By ~ 2

Author(s):

Qiong Liu ◽

Yuheng Gong ◽

Yuqin Cao ◽

Xintian Wen ◽

Xiaobo Huang ◽

...

Keyword(s):

Mutant Strain ◽

Vaccine Strain ◽

Parent Strain ◽

Actinobacillus Pleuropneumoniae ◽

Haemolytic Activity ◽

Live Vaccine Strain ◽

Haemophilus Parasuis ◽

Rtx Toxins ◽

Counter Selection ◽

Foreign Dna

The apxIC genes of the Actinobacillus pleuropneumoniae serovar 5 (SC-1), encoding the ApxIactivating proteins, was deleted by a method involving sucrose counter-selection. In this study, a mutant strain of A. pleuropneumoniae (SC-1) was constructed and named DapxIC/ ompP2. The mutant strain contained foreign DNA in the deletion site of ompP2 gene of Haemophilus parasuis. It showed no haemolytic activity and lower virulence of cytotoxicity in mice compared with the parent strain, and its safety and immunogenicity were also evaluated in mice. The LD50 data shown that the mutant strain was attenuated 30-fold, compared with the parent strain (LD50 of the mutant strain and parent strain in mice were determined to be 1.0 × 107 CFU and 3.5 × 105 CFU respectively). The mutant strain that was attenuated could secrete inactivated ApxIA RTX toxins with complete antigenicity and could be used as a candidate live vaccine strain against infections of A. pleuropneumoniae and H. parasuis.

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Attenuation of Vaccinia Virus

Acta Naturae ◽

10.32607/20758251-2015-7-4-113-121 ◽

2015 ◽

Vol 7 (4) ◽

pp. 113-121 ◽

Cited By ~ 2

Author(s):

S. N. Yakubitskiy ◽

I. V. Kolosova ◽

R. A. Maksyutov ◽

S. N. Shchelkunov

Keyword(s):

Vaccinia Virus ◽

Vaccine Strain ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Virulence Genes ◽

Binding Protein ◽

Smallpox Vaccination ◽

Lethal Challenge ◽

Mammalian Cell Cultures ◽

Genes Encoding

Since 1980, in the post-smallpox vaccination era the human population has become increasingly susceptible compared to a generation ago to not only the variola (smallpox) virus, but also other zoonotic orthopoxviruses. The need for safer vaccines against orthopoxviruses is even greater now. The Lister vaccine strain (LIVP) of vaccinia virus was used as a parental virus for generating a recombinant 1421ABJCN clone defective in five virulence genes encoding hemagglutinin (A56R), the IFN--binding protein (B8R), thymidine kinase (J2R), the complement-binding protein (C3L), and the Bcl-2-like inhibitor of apoptosis (N1L). We found that disruption of these loci does not affect replication in mammalian cell cultures. The isogenic recombinant strain 1421ABJCN exhibits a reduced inflammatory response and attenuated neurovirulence relative to LIVP. Virus titers of 1421ABJCN were 3 lg lower versus the parent VACV LIVP when administered by the intracerebral route in new-born mice. In a subcutaneous mouse model, 1421ABJCN displayed levels of VACV-neutralizing antibodies comparable to those of LIVP and conferred protective immunity against lethal challenge by the ectromelia virus. The VACV mutant holds promise as a safe live vaccine strain for preventing smallpox and other orthopoxvirus infections.

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Distribution of Tetracycline Resistance Genes in Actinobacillus pleuropneumoniae Isolates from Spain

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.50.2.702-708.2006 ◽

2006 ◽

Vol 50 (2) ◽

pp. 702-708 ◽

Cited By ~ 19

Author(s):

Mónica Blanco ◽

César B. Gutiérrez-Martin ◽

Elías F. Rodríguez-Ferri ◽

Marilyn C. Roberts ◽

Jesús Navas

Keyword(s):

Tetracycline Resistance ◽

Actinobacillus Pleuropneumoniae ◽

Open Reading Frames ◽

The Other ◽

Gram Negative Bacteria ◽

Gene Encoding ◽

Tetracycline Resistance Genes ◽

Porcine Pleuropneumonia ◽

Gene Coding ◽

Reading Frames

ABSTRACT Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia. Tetracycline is used for therapy of this disease, and A. pleuropneumoniae carrying the tet(B) gene, coding for an efflux protein that reduces the intercellular tetracycline level, has been described previously. Of the 46 tetracycline-resistant (Tcr) Spanish A. pleuropneumoniae isolates used in this study, 32 (70%) carried the tet(B) gene, and 30 of these genes were associated with plasmids. Eight (17%) isolates carried the tet(O) gene, two (4%) isolates carried either the tet(H) or the tet(L) gene, and all these genes were associated with plasmids. This is the first description of these tet genes in A. pleuropneumoniae. The last two Tcr isolates carried none of the tet genes examined. Except for tet(O)-containing plasmids, the other 34 Tcr plasmids were transformable into an Escherichia coli recipient. Two plasmids were completely sequenced. Plasmid p11745, carrying the tet(B) gene, was 5,486 bp and included a rep gene, encoding a replication-related protein, and two open reading frames (ORFs) with homology to mobilization genes of Neisseria gonorrhoeae plasmid pSJ7.4. Plasmid p9555, carrying the tet(L) gene, was 5,672 bp and, based on its G+C content, consisted of two regions, one of putative gram-positive origin containing the tet(L) gene and the other comprising four ORFs organized in an operon-like structure with homology to mobilization genes in other plasmids of gram-negative bacteria.

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Sero- and apx-typing of German Actinobacillus pleuropneumoniae field isolates from 2010 to 2019 reveals a predominance of serovar 2 with regular apx-profile

Veterinary Research ◽

10.1186/s13567-020-00890-x ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Lukas Schuwerk ◽

Doris Hoeltig ◽

Karl-Heinz Waldmann ◽

Peter Valentin-Weigand ◽

Judith Rohde

Keyword(s):

Reference Strain ◽

Actinobacillus Pleuropneumoniae ◽

Etiological Agent ◽

Toxin Gene ◽

Gene Profile ◽

Field Isolates ◽

Porcine Pleuropneumonia ◽

Virulent Strains ◽

Highly Virulent

AbstractSerotyping is the most common method to characterize field isolates of Actinobacillus (A.) pleuropneumoniae, the etiological agent of porcine pleuropneumonia. Based on serology, many farms seem to be infected and antibodies against a wide variety of serovars are detectable, but, so far it is unknown to what degree respective serovars contribute to outbreaks of clinical manifest disease. In this study, 213 German A. pleuropneumoniae field isolates retrieved for diagnostic purposes from outbreaks of porcine pleuropneumonia between 2010 and 2019 were genetically serotyped and analyzed regarding their apx-toxin gene profile using molecular methods. Serotyping revealed a prominent role of serovar 2 in clinical cases (64% of all isolates) and an increase in the detection of this serovar since 2010 in German isolates. Serovar 9/11 followed as the second most frequent serovar with about 15% of the isolates. Furthermore, very recently described serovars 16 (n = 2) and 18 (n = 8) were detected. Most isolates (93.4%) showed apx-profiles typical for the respective serovar. However, this does not hold true for isolates of serovar 18, as 75% (n = 6) of all isolates of this serovar deviated uniformly from the “typical” apx-gene profile of the reference strain 7311555. Notably, isolates from systemic lesions such as joints or meninges did not harbor the complete apxICABD operon which is considered typical for highly virulent strains. Furthermore, the extremely low occurrence (n = 1) of NAD independent (biovar II) isolates in German A. pleuropneumoniae was evident in our collection of clinical isolates.

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Protective immunity induced by peptides of AMA1, RON2 and RON4 containing T-and B-cell epitopes via an intranasal route against toxoplasmosis in mice

Parasites & Vectors ◽

10.1186/s13071-015-0636-5 ◽

2015 ◽

Vol 8 (1) ◽

pp. 15 ◽

Cited By ~ 19

Author(s):

Tie-E Zhang ◽

Li-Tian Yin ◽

Run-Hua Li ◽

Hai-Long Wang ◽

Xiao-Li Meng ◽

...

Keyword(s):

B Cell ◽

Protective Immunity ◽

Intranasal Route ◽

B Cell Epitopes

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Correlates of Immune Protection following Cutaneous Immunization with an Attenuated Burkholderia pseudomallei Vaccine

Infection and Immunity ◽

10.1128/iai.00915-13 ◽

2013 ◽

Vol 81 (12) ◽

pp. 4626-4634 ◽

Cited By ~ 26

Author(s):

Ediane B. Silva ◽

Andrew Goodyear ◽

Marjorie D. Sutherland ◽

Nicole L. Podnecky ◽

Mercedes Gonzalez-Juarrero ◽

...

Keyword(s):

Immune Responses ◽

Vaccine Strain ◽

Protective Immunity ◽

Burkholderia Pseudomallei ◽

Partial Protection ◽

Content Type ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Immune Correlates ◽

Draining Lymph Nodes

ABSTRACTInfections with the Gram-negative bacteriumBurkholderia pseudomallei(melioidosis) are associated with high mortality, and there is currently no approved vaccine to prevent the development of melioidosis in humans. Infected patients also do not develop protective immunity to reinfection, and some individuals will develop chronic, subclinical infections withB. pseudomallei. At present, our understanding of what constitutes effective protective immunity againstB. pseudomalleiinfection remains incomplete. Therefore, we conducted a study to elucidate immune correlates of vaccine-induced protective immunity against acuteB. pseudomalleiinfection. BALB/c and C57BL/6 mice were immunized subcutaneously with a highly attenuated, Select Agent-excludedpurMdeletion mutant ofB. pseudomallei(strain Bp82) and then subjected to intranasal challenge with virulentB. pseudomalleistrain 1026b. Immunization with Bp82 generated significant protection from challenge withB. pseudomallei, and protection was associated with a significant reduction in bacterial burden in lungs, liver, and spleen of immunized mice. Humoral immunity was critically important for vaccine-induced protection, as mice lacking B cells were not protected by immunization and serum from Bp82-vaccinated mice could transfer partial protection to nonvaccinated animals. In contrast, vaccine-induced protective immunity was found to be independent of both CD4 and CD8 T cells. Tracking studies demonstrated uptake of the Bp82 vaccine strain predominately by neutrophils in vaccine-draining lymph nodes and by smaller numbers of dendritic cells (DC) and monocytes. We concluded that protection following cutaneous immunization with a live attenuatedBurkholderiavaccine strain was dependent primarily on generation of effective humoral immune responses.

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Phase Variation of Campylobacter jejuni 81-176 Lipooligosaccharide Affects Ganglioside Mimicry and Invasiveness In Vitro

Infection and Immunity ◽

10.1128/iai.70.2.787-793.2002 ◽

2002 ◽

Vol 70 (2) ◽

pp. 787-793 ◽

Cited By ~ 154

Author(s):

Patricia Guerry ◽

Christine M. Szymanski ◽

Martina M. Prendergast ◽

Thomas E. Hickey ◽

Cheryl P. Ewing ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Phase Variation ◽

Outer Core ◽

Gene Encoding ◽

Site Specific ◽

Reading Frame ◽

Specific Mutation ◽

Normal Human ◽

A Site

ABSTRACT The outer cores of the lipooligosaccharides (LOS) of many strains of Campylobacter jejuni mimic human gangliosides in structure. A population of cells of C. jejuni strain 81-176 produced a mixture of LOS cores which consisted primarily of structures mimicking GM2 and GM3 gangliosides, with minor amounts of structures mimicking GD1b and GD2. Genetic analyses of genes involved in the biosynthesis of the outer core of C. jejuni 81-176 revealed the presence of a homopolymeric tract of G residues within a gene encoding CgtA, an N-acetylgalactosaminyltransferase. Variation in the number of G residues within cgtA affected the length of the open reading frame, and these changes in cgtA corresponded to a change in LOS structure from GM2 to GM3 ganglioside mimicry. Site-specific mutation of cgtA in 81-176 resulted in a major LOS core structure that lacked GalNAc and resembled GM3 ganglioside. Compared to wild-type 81-176, the cgtA mutant showed a significant increase in invasion of INT407 cells. In comparison, a site-specific mutation of the neuC1 gene resulted in the loss of sialic acid in the LOS core and reduced resistance to normal human serum but had no affect on invasion of INT407 cells.

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Regulation of the Bacillus subtilis bcrC Bacitracin Resistance Gene by Two Extracytoplasmic Function σ Factors

Journal of Bacteriology ◽

10.1128/jb.184.22.6123-6129.2002 ◽

2002 ◽

Vol 184 (22) ◽

pp. 6123-6129 ◽

Cited By ~ 91

Author(s):

Min Cao ◽

John D. Helmann

Keyword(s):

Bacillus Subtilis ◽

Resistance Gene ◽

Mutant Strain ◽

Stress Responses ◽

Double Mutant ◽

De Novo ◽

De Novo Synthesis ◽

Gene Encoding ◽

Single Promoter ◽

Higher Sensitivity

ABSTRACT Bacitracin resistance is normally conferred by either of two major mechanisms, the BcrABC transporter, which pumps out bacitracin, or BacA, an undecaprenol kinase that provides C55-isoprenyl phosphate by de novo synthesis. We demonstrate that the Bacillus subtilis bcrC (ywoA) gene, encoding a putative bacitracin transport permease, is an important bacitracin resistance determinant. A bcrC mutant strain had an eightfold-higher sensitivity to bacitracin. Expression of bcrC initiated from a single promoter site that could be recognized by either of two extracytoplasmic function (ECF) σ factors, σX or σM. Bacitracin induced expression of bcrC, and this induction was dependent on σM but not on σX. Under inducing conditions, expression was primarily dependent on σM. As a consequence, a sigM mutant was fourfold more sensitive to bacitracin, while the sigX mutant was only slightly sensitive. A sigX sigM double mutant was similar to a bcrC mutant in sensitivity. These results support the suggestion that one function of B. subtilis ECF σ factors is to coordinate antibiotic stress responses.

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Nucleocapsid vaccine elicits spike-independent SARS-CoV-2 protective immunity

10.1101/2021.04.26.441518 ◽

2021 ◽

Author(s):

William E. Matchett ◽

Vineet Joag ◽

J. Michael Stolley ◽

Frances K. Shepherd ◽

Clare F. Quarnstrom ◽

...

Keyword(s):

Weight Loss ◽

Viral Load ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Protein A ◽

Receptor Binding Domain ◽

Immune Effector ◽

N Protein ◽

Viral Antigens ◽

Successful Vaccine

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing antibodies target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with HAd5 expressing the nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and k18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral antigens, even if they are not a target of neutralizing antibodies, to broaden epitope coverage and immune effector mechanisms.

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