Evaluation of Brucella abortus Phosphoglucomutase (pgm) Mutant as a New Live Rough-Phenotype Vaccine

ABSTRACT Brucella abortus S19 is the vaccine most frequently used against bovine brucellosis. Although it induces good protection levels, it cannot be administered to pregnant cattle, revaccination is not advised due to interference in the discrimination between infected and vaccinated animals during immune-screening procedures, and the vaccine is virulent for humans. Due to these reasons, there is a continuous search for new bovine vaccine candidates that may confer protection levels comparable to those conferred by S19 but without its disadvantages. A previous study characterized the phenotype associated with the phosphoglucomutase (pgm) gene disruption in Brucella abortus S2308, as well as the possible role for the smooth lipopolysaccharide (LPS) in virulence and intracellular multiplication in HeLa cells (J. E. Ugalde, C. Czibener, M. F. Feldman, and R. A. Ugalde, Infect. Immun. 68:5716-5723, 2000). In this report, we analyze the protection, proliferative response, and cytokine production induced in BALB/c mice by a Δpgm deletion strain. We show that this strain synthesizes O antigen with a size of approximately 45 kDa but is rough. This is due to the fact that the Δpgm strain is unable to assemble the O side chain in the complete LPS. Vaccination with the Δpgm strain induced protection levels comparable to those induced by S19 and generated a proliferative splenocyte response and a cytokine profile typical of a Th1 response. On the other hand, we were unable to detect a specific anti-O-antigen antibody response by using the fluorescence polarization assay. In view of these results, the possibility that the Δpgm mutant could be used as a vaccination strain is discussed.

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Identification and Characterization of the Brucella abortus Phosphoglucomutase Gene: Role of Lipopolysaccharide in Virulence and Intracellular Multiplication

Infection and Immunity ◽

10.1128/iai.68.10.5716-5723.2000 ◽

2000 ◽

Vol 68 (10) ◽

pp. 5716-5723 ◽

Cited By ~ 82

Author(s):

Juan E. Ugalde ◽

Cecilia Czibener ◽

Mario F. Feldman ◽

Rodolfo A. Ugalde

Keyword(s):

Brucella Abortus ◽

Wild Type ◽

Protective Properties ◽

O Antigen ◽

Important Virulence Factor ◽

Intracellular Multiplication ◽

Identification And Characterization ◽

Precise Role

ABSTRACT Smooth lipopolysaccharide (LPS) of Brucella abortus has been reported to be an important virulence factor, although its precise role in pathogenesis is not yet clear. While the protective properties of LPS against complement are well accepted, there is still some controversy about the capacity of rough mutants to replicate intracellularly. The B. abortus phosphoglucomutase gene (pgm) was cloned, sequenced, and disrupted. The gene has a high index of identity to Agrobacterium tumefaciens pgm but is not part of the glycogen operon. A B. abortus null mutant lacks LPS O antigen but has an LPS core with an electrophoretic profile undistinguishable from that of the wild-type core, suggesting that glucose, galactose, or a derivative of these sugars may be part of the linkage between the core and the O antigen. This mutant is unable to survive in mice but replicates in HeLa cells, indicating that the complete LPS is not essential either for invasion or for intracellular multiplication. This behavior suggests that the LPS may play a role in extracellular survival in the animal, probably protecting the cell against complement-mediated lysis, but is not involved in intracellular survival.

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The Relevance of Bioinformatics Applications in the Discovery of Vaccine Candidates and Potential Drugs for COVID-19 Treatment

Bioinformatics and Biology Insights ◽

10.1177/11779322211002168 ◽

2021 ◽

Vol 15 ◽

pp. 117793222110021

Author(s):

Onyeka S Chukwudozie ◽

Vincent C Duru ◽

Charlotte C Ndiribe ◽

Abdullahi T Aborode ◽

Victor O Oyebanji ◽

...

Keyword(s):

Viral Genome ◽

Drug Repurposing ◽

Protein Docking ◽

Vaccine Research ◽

Vaccine Candidates ◽

Genome Data ◽

Disease Agent ◽

Time Critical ◽

Antigen Antibody ◽

Antigenic Epitopes

The application of bioinformatics to vaccine research and drug discovery has never been so essential in the fight against infectious diseases. The greatest combat of the 21st century against a debilitating disease agent SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus discovered in Wuhan, China, December 2019, has piqued an unprecedented usage of bioinformatics tools in deciphering the molecular characterizations of infectious pathogens. With the viral genome data of SARS-COV-2 been made available barely weeks after the reported outbreak, bioinformatics platforms have become an all-time critical tool to gain time in the fight against the disease pandemic. Before the outbreak, different platforms have been developed to explore antigenic epitopes, predict peptide-protein docking and antibody structures, and simulate antigen-antibody reactions and lots more. However, the advent of the pandemic witnessed an upsurge in the application of these pipelines with the development of newer ones such as the Coronavirus Explorer in the development of efficacious vaccines, drug repurposing, and/or discovery. In this review, we have explored the various pipelines available for use, their relevance, and limitations in the timely development of useful therapeutic candidates from genomic data knowledge to clinical therapy.

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Immune Responses and Protection against Experimental Brucella suis Biovar 1 Challenge in Nonvaccinated or B. abortus Strain RB51-Vaccinated Cattle

Clinical and Vaccine Immunology ◽

10.1128/cvi.00326-10 ◽

2010 ◽

Vol 17 (12) ◽

pp. 1891-1895 ◽

Cited By ~ 11

Author(s):

S. C. Olsen ◽

S. G. Hennager

Keyword(s):

Immune Responses ◽

Experimental Infection ◽

Brucella Abortus ◽

Agglutination Test ◽

Saline Control ◽

Infected Cattle ◽

Infection Rates ◽

Treatment Groups ◽

Brucella Suis ◽

Fluorescence Polarization Assay

ABSTRACT Twenty Hereford heifers approximately 9 months of age were vaccinated with saline (control) or 2 × 1010 CFU of the Brucella abortus strain RB51 (RB51) vaccine. Immunologic responses after inoculation demonstrated significantly greater (P < 0.05) antibody and proliferative responses to RB51 antigens in cattle vaccinated with RB51 than in the controls. Pregnant cattle received a conjunctival challenge at approximately 6 months of gestation with 107 CFU of B. suis bv. 1 strains isolated from naturally infected cattle. The fluorescence polarization assay and the buffered acid plate agglutination test had the highest sensitivities in detecting B. suis-infected cattle between 2 and 12 weeks after experimental infection. Serologic responses and lymphocyte proliferative responses to B. suis antigens did not differ between control and RB51 vaccinees after experimental infection. No abortions occurred in cattle in either treatment group after challenge, although there appeared to be an increased incidence of retained placenta after parturition in both the control and the RB51 vaccination treatment groups. Our data suggest that the mammary gland is a preferred site for B. suis localization in cattle. Vaccination with RB51 did not reduce B. suis infection rates in maternal or fetal tissues. In conclusion, although B. suis is unlikely to cause abortions and fetal losses in cattle, our data suggest that RB51 vaccination will not protect cattle against B. suis infection after exposure.

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Fluorescence Polarization Assay: Application to the Diagnosis of Bovine Brucellosis in Argentina

Journal of Immunoassay ◽

10.1080/01971529909349347 ◽

1999 ◽

Vol 20 (3) ◽

pp. 115-126 ◽

Cited By ~ 12

Author(s):

L. Samartino ◽

R. Gregoret ◽

D. Gall ◽

K. Nielsen

Keyword(s):

Fluorescence Polarization ◽

Bovine Brucellosis ◽

Fluorescence Polarization Assay

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Characterization of O-antigen delivered by Generalized Modules for Membrane Antigens (GMMA) vaccine candidates against nontyphoidal Salmonella

Vaccine ◽

10.1016/j.vaccine.2016.11.089 ◽

2017 ◽

Vol 35 (3) ◽

pp. 419-426 ◽

Cited By ~ 19

Author(s):

G. De Benedetto ◽

R. Alfini ◽

P. Cescutti ◽

M. Caboni ◽

L. Lanzilao ◽

...

Keyword(s):

Vaccine Candidates ◽

O Antigen ◽

Membrane Antigens

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Efficacy of bovine brucellosis vaccines: conceptions, challenges and meta‐analysis. Response to the Letter to the Editor concerning “Efficacy of Brucella abortus S19 and RB51 vaccine strains: A systematic review and meta‐analysis” by Blasco et al (Transbound Emerg Dis; 2021: https://doi.org/10.1111/tbed.14259)

Transboundary and Emerging Diseases ◽

10.1111/tbed.14442 ◽

2021 ◽

Author(s):

Elaine Maria Seles Dorneles ◽

Andrey Pereira Lage ◽

Júlio Silvio de Sousa Bueno Filho ◽

Jacques Godfroid ◽

Carine Rodrigues Pereira

Keyword(s):

Systematic Review ◽

Brucella Abortus ◽

Meta Analysis ◽

Bovine Brucellosis ◽

Letter To The Editor

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Bovine brucellosis in slaughterhouses controlled by Federal and Municipal Inspection Services in the state of Maranhão, Brazil

Arquivos do Instituto Biológico ◽

10.1590/1808-1657000832017 ◽

2019 ◽

Vol 86 ◽

Author(s):

Anna Karoline Amaral Sousa ◽

Bruno Raphael Ribeiro Guimarães ◽

Priscila Alencar Beserra ◽

Danilo Cutrim Bezerra ◽

Ferdinan de Almeida Melo ◽

...

Keyword(s):

Risk Factors ◽

Brucella Abortus ◽

Bovine Brucellosis ◽

Blood Samples ◽

Male And Female ◽

Specific Antibodies ◽

Laboratory Results ◽

Inspection Service ◽

Serum Agglutination ◽

Do So

ABSTRACT: The aims of the current study were to investigate the prevalence of bovine brucellosis, to correlate laboratory results of serum reactive samples to the serology of animals presenting serous pouches, and to identify possible risk factors for the development of the disease. In order to do so, 1,265 bovine blood samples were collected from male and female animals bred in different counties in Maranhão state, Brazil, and in other regions of the country. The animals were slaughtered in two slaughterhouses controlled by the Federal Inspection Service (FIS), and in two others controlled by the Municipal Inspection Service (MIS), of regions such as Açailândia and Imperatriz. Samples were tested for specific antibodies by using buffered acidified antigen (BAA) and 2-mercaptoethanol in combination with slow serum agglutination (2-ME + SSA). Additionally, an epidemiological questionnaire was applied to 100 owners, who provided animals to the slaughterhouses, to enable investigating the risk factors for bovine brucellosis. Fifteen serous pouches of animals presenting this lesion were also collected at slaughter time. Thirty-nine out of the analyzed samples were reacted to BAA, whereas 15 reacted to the 2-ME + SSA test; only one male was reagent and it resulted in 1.19% prevalence. One out of the 15 collected serous pouches reacted to the 2-ME + SSA test. The risk factors identified in this study were: the incidence of miscarriages, the sale of animals without previous examination, and the failure in testing the animals before introducing them in herds and before slaughter. It was possible to conclude that the animals slaughtered in the herein evaluated slaughterhouses were infected with Brucella abortus, as well as that this infection prevailed in females.

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Design, Construction, and Two Applications for an Automated Flow—Cell Polarization Fluorometer with Digital Read Out: Enzyme-Inhibitor (Antitrypsin) Assay and Antigen—Antibody (Insulin—Insulin Antiserum) Assay

Clinical Chemistry ◽

10.1093/clinchem/19.8.838 ◽

1973 ◽

Vol 19 (8) ◽

pp. 838-844 ◽

Cited By ~ 56

Author(s):

Richard D Spencer ◽

Fernando B Toledo ◽

Ben T Williams ◽

Norma L Yoss

Keyword(s):

Fluorescence Polarization ◽

Enzyme Inhibitor ◽

Flow Cell ◽

Cell Polarization ◽

Digital Data ◽

Multiple Components ◽

Digital Data Processing ◽

Fluorescence Polarization Assay ◽

Antigen Antibody ◽

Design Construction

Abstract We have constructed and automated a flow cell polarization fluorometer and demonstrated two specific clinical applications of fluorescence polarization assay, i.e., the enzyme-inhibitor assay of antitrypsin in serum and the antigen-antibody assay of insulin and its antibody. A signal is displayed directly and is immediately available for chart recording and (or) digital data processing. Since fluorescence polarization offers a number of choices in assay parameters and the use of different fluorescent probes, its development for rapid simultaneous measurements of multiple components in body fluids should be possible.

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