O-antigen structure in a virulent strain ofAeromonas hydrophila

ABSTRACTFrancisella tularensisis capable of rampant intracellular growth and causes a potentially fatal disease in humans. Whereas many mutational studies have been performed with avirulent strains ofFrancisella, relatively little has been done with strains that cause human disease. We generated a near-saturating transposon library in the virulent strain Schu S4, which was subjected to high-throughput screening by transposon site hybridization through primary human macrophages, negatively selecting 202 genes. Of special note were genes in a locus of theFrancisellachromosome,FTT1236,FTT1237, andFTT1238. Mutants with mutations in these genes demonstrated significant sensitivity to complement-mediated lysis compared with wild-type Schu S4 and exhibited marked defects in O-antigen and capsular polysaccharide biosynthesis. In the absence of complement, these mutants were phagocytosed more efficiently by macrophages than wild-type Schu S4 and were capable of phagosomal escape but exhibited reduced intracellular growth. Microscopic and quantitative analyses of macrophages infected with mutant bacteria revealed that these macrophages exhibited signs of cell death much earlier than those infected with Schu S4. These data suggest thatFTT1236,FTT1237, andFTT1238are important for polysaccharide biosynthesis and that theFrancisellaO antigen, capsule, or both are important for avoiding the early induction of macrophage death and the destruction of the replicative niche.

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O-antigen structure and gene clusters of Escherichia coli O51 and Salmonella enterica O57; another instance of identical O-antigens in the two species

Carbohydrate Research ◽

10.1016/j.carres.2011.02.020 ◽

2011 ◽

Vol 346 (6) ◽

pp. 828-832 ◽

Cited By ~ 4

Author(s):

Andrei V. Perepelov ◽

Bin Liu ◽

Sof’ya N. Senchenkova ◽

Dan Guo ◽

Sergei D. Shevelev ◽

...

Keyword(s):

Escherichia Coli ◽

Salmonella Enterica ◽

Gene Clusters ◽

O Antigen ◽

O Antigens ◽

Antigen Structure

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Complex Bfr-O-Antigen of Francisella tularensis Outer Membranes: Production, Characteristics and Potential Use

Biotekhnologiya ◽

10.21519/0234-2758-2019-35-1-73-81 ◽

2019 ◽

Vol 35 (1) ◽

pp. 73-81

Author(s):

O.A. Volokh ◽

Ya.M. Krasnov ◽

Т.А. Polunina ◽

N.G. Avdeeva ◽

Yu.I. Samokhvalova ◽

...

Keyword(s):

Francisella Tularensis ◽

Technical Assistance ◽

Virulent Strain ◽

Outer Membrane Proteins ◽

Tularensis Subsp ◽

Outer Membranes ◽

O Antigen ◽

Antigenic Complex ◽

Potential Use ◽

Production Characteristics

A method for the isolation of a complex antigen of protein-carbohydrate nature from outer membranes of the vaccine strain Francisella tularensis subsp. holarctica 15 NIIEG cells and its detailed characteristics have been described. A protein of bacterioferritin (Bfr) and O-antigen were identified in the antigenic complex. It was shown that the obtained complex antigen is non-toxic, harmless, has high immunogenic activity and protects white mice in the subcutaneous infection with a virulent strain of F. tularensis subsp. holarctica 503/840. This antigen was shown to occur in the tularemia microbe regardless of the subspecies and presence of a capsule. The high antigenic and immunobiological activity of the Bfr-O-antigen complex provides the prerequisites for its further use as a component in the development of preventive and diagnostic drugs against the tularemia infection. Francisella tularensis, antigens, outer membrane proteins, immunogenicity, lipopoly saccharide, O-antigen. Authors would like to thank to the staff of the Institute «Microbe»: laboratory of molecular diagnostics I.V. Terekhova for providing us with the monoclonal antibodies, laboratories for genomic and proteomic analysis N.V. Kotova for her excellent technical assistance.

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Protective Properties of Rifampin-Resistant Rough Mutants of Brucella melitensis

Infection and Immunity ◽

10.1128/iai.73.7.4198-4204.2005 ◽

2005 ◽

Vol 73 (7) ◽

pp. 4198-4204 ◽

Cited By ~ 27

Author(s):

R. Adone ◽

F. Ciuchini ◽

C. Marianelli ◽

M. Tarantino ◽

C. Pistoia ◽

...

Keyword(s):

Brucella Melitensis ◽

Virulent Strain ◽

Resistant Mutant ◽

Preliminary Evidence ◽

Primary Host ◽

Protective Properties ◽

O Antigen ◽

Rough Strain ◽

Cellular Immune ◽

Rough Mutant

ABSTRACT Vaccination against Brucella infections in animals is usually performed by administration of live attenuated smooth B. abortus strain S19 and B. melitensis strain Rev1. They are proven effective vaccines against B. abortus in cattle and against B. melitensis and B. ovis in sheep and goats, respectively. However, both vaccines have the main drawback of inducing O-polysaccharide-specific antibodies that interfere with serologic diagnosis of disease. In addition, they retain residual virulence, being a cause of abortion in pregnant animals and infection in humans. To overcome these problems, one approach is to develop defined rough mutant Brucella strains lacking O antigen of lipopolysaccharide. B. abortus rough strain RB51, a rifampin-resistant mutant of virulent strain B. abortus 2308, is used as a vaccine against B. abortus infection in cattle in some countries. However, RB51 is not effective in sheep, and there is only preliminary evidence that it is effective in goats. In this study, we tested the efficacies of six rifampin-resistant rough strains of B. melitensis in protecting BALB/c mice exposed to B. melitensis infection. The protective properties, as well as both humoral and cellular immune responses, were assessed in comparison with those provided by B. melitensis Rev1 and B. abortus RB51 vaccines. The results indicated that these rough mutants were able to induce a very good level of protection against B. melitensis infection, similar to that provided by Rev1 and superior to that of RB51, without inducing antibodies to O antigen. In addition, all B. melitensis mutants were able to stimulate good production of gamma interferon. The characteristics of these strains encourage further evaluation of them as alternative vaccines to Rev1 in primary host species.

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Structure of the O-antigen of Salmonella O66 and the genetic basis for similarity and differences between the closely related O-antigens of Escherichia coli O166 and Salmonella O66

Microbiology ◽

10.1099/mic.0.037325-0 ◽

2010 ◽

Vol 156 (6) ◽

pp. 1642-1649 ◽

Cited By ~ 10

Author(s):

Bin Liu ◽

Andrei V. Perepelov ◽

Dan Li ◽

Sof'ya N. Senchenkova ◽

Yanfang Han ◽

...

Keyword(s):

Escherichia Coli ◽

Gene Cluster ◽

Gene Clusters ◽

Coding Region ◽

E Coli ◽

Antigen Gene ◽

O Antigen ◽

New Genes ◽

O Antigens ◽

Antigen Structure

O-antigen is a component of the outer membrane of Gram-negative bacteria and is one of the most variable cell surface constituents, leading to major antigenic variability. The O-antigen forms the basis for bacterial serotyping. In this study, the O-antigen structure of Salmonella O66 was established, which differs from the known O-antigen structure of Escherichia coli O166 only in one linkage (most likely the linkage between the O-units) and O-acetylation. The O-antigen gene clusters of Salmonella O66 and E. coli O166 were found to have similar organizations, the only exception being that in Salmonella O66, the wzy gene is replaced by a non-coding region. The function of the wzy gene in E. coli O166 was confirmed by the construction and analysis of deletion and trans-complementation mutants. It is proposed that a functional wzy gene located outside the O-antigen gene cluster is involved in Salmonella O66 O-antigen biosynthesis, as has been reported previously in Salmonella serogroups A, B and D1. The sequence identity for the corresponding genes between the O-antigen gene clusters of Salmonella O66 and E. coli O166 ranges from 64 to 70 %, indicating that they may originate from a common ancestor. It is likely that after the species divergence, Salmonella O66 got its specific O-antigen form by inactivation of the wzy gene located in the O-antigen gene cluster and acquisition of two new genes (a wzy gene and a prophage gene for O-acetyl modification) both residing outside the O-antigen gene cluster.

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Structural Determination and Genetic Identification of the O-Antigen from an Escherichia coli Strain, LL004, Representing a Novel Serogroup

International Journal of Molecular Sciences ◽

10.3390/ijms222312746 ◽

2021 ◽

Vol 22 (23) ◽

pp. 12746

Author(s):

Jing Wang ◽

Yujuan Xu ◽

Chunjun Qin ◽

Jing Hu ◽

Jian Yin ◽

...

Keyword(s):

Escherichia Coli ◽

Nmr Spectra ◽

Coli Strain ◽

Genetic Identification ◽

Gram Negative Bacteria ◽

Gram Negative ◽

E Coli ◽

O Antigen ◽

Antigen Structure ◽

Dependent Pathway

The O-antigen is the outermost component of the lipopolysaccharide layer in Gram-negative bacteria, and the variation of O-antigen structure provides the basis for bacterial serological diversity. Here, we determined the O-antigen structure of an Escherichia coli strain, LL004, which is totally different from all of the E. coli serogroups. The tetrasaccharide repeating unit was determined as →4)-β-d-Galp-(1→3)-β-d-GlcpNAc6OAc(~70%)-(1→3)-β-d-GalpA-(1→3)-β-d-GalpNAc-(1→ with monosaccharide analysis and NMR spectra. We also characterized the O-antigen gene cluster of LL004, and sequence analysis showed that it correlated well with the O-antigen structure. Deletion and complementation testing further confirmed its role in O-antigen biosynthesis, and indicated that the O-antigen of LL004 is assembled via the Wzx/Wzy dependent pathway. Our findings, in combination, suggest that LL004 should represent a novel serogroup of E. coli.

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O-antigen structure of Shigella flexneri serotype Yv and effect of the lpt-O gene variation on phosphoethanolamine modification of S. flexneri O-antigens

Glycobiology ◽

10.1093/glycob/cws222 ◽

2013 ◽

Vol 23 (4) ◽

pp. 475-485 ◽

Cited By ~ 20

Author(s):

Y. A. Knirel ◽

R. Lan ◽

S. N. Senchenkova ◽

J. Wang ◽

A. S. Shashkov ◽

...

Keyword(s):

Shigella Flexneri ◽

Gene Variation ◽

O Antigen ◽

O Antigens ◽

Antigen Structure

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Increased severity of respiratory infections associated with elevated anti-LPS IgG2 which inhibits serum bactericidal killing

Journal of Experimental Medicine ◽

10.1084/jem.20132444 ◽

2014 ◽

Vol 211 (9) ◽

pp. 1893-1904 ◽

Cited By ~ 38

Author(s):

Timothy J. Wells ◽

Deborah Whitters ◽

Yanina R. Sevastsyanovich ◽

Jennifer N. Heath ◽

John Pravin ◽

...

Keyword(s):

Respiratory Infections ◽

Natural Infection ◽

Gram Negative Bacteria ◽

Inhibitory Antibody ◽

Gram Negative ◽

O Antigen ◽

Excess Production ◽

Blocking Antibodies ◽

Antigen Structure ◽

Induce Antibody

Although specific antibody induced by pathogens or vaccines is a key component of protection against infectious threats, some viruses, such as dengue, induce antibody that enhances the development of infection. In contrast, antibody-dependent enhancement of bacterial infection is largely unrecognized. Here, we demonstrate that in a significant portion of patients with bronchiectasis and Pseudomonas aeruginosa lung infection, antibody can protect the bacterium from complement-mediated killing. Strains that resist antibody-induced, complement-mediated killing produce lipopolysaccharide containing O-antigen. The inhibition of antibody-mediated killing is caused by excess production of O-antigen–specific IgG2 antibodies. Depletion of IgG2 to O-antigen restores the ability of sera to kill strains with long-chain O-antigen. Patients with impaired serum-mediated killing of P. aeruginosa by IgG2 have poorer respiratory function than infected patients who do not produce inhibitory antibody. We suggest that excessive binding of IgG2 to O-antigen shields the bacterium from other antibodies that can induce complement-mediated killing of bacteria. As there is significant sharing of O-antigen structure between different Gram-negative bacteria, this IgG2-mediated impairment of killing may operate in other Gram-negative infections. These findings have marked implications for our understanding of protection generated by natural infection and for the design of vaccines, which should avoid inducing such blocking antibodies.

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Complementation of Brucella abortus RB51 with a Functional wboA Gene Results in O-Antigen Synthesis and Enhanced Vaccine Efficacy but No Change in Rough Phenotype and Attenuation

Infection and Immunity ◽

10.1128/iai.68.7.3927-3932.2000 ◽

2000 ◽

Vol 68 (7) ◽

pp. 3927-3932 ◽

Cited By ~ 50

Author(s):

Ramesh Vemulapalli ◽

Yongqun He ◽

Larissa S. Buccolo ◽

Stephen M. Boyle ◽

Nammalwar Sriranganathan ◽

...

Keyword(s):

Brucella Abortus ◽

Brucella Melitensis ◽

Virulent Strain ◽

Polymyxin B ◽

Gamma Interferon ◽

T Cell Response ◽

Bacterial Cells ◽

O Antigen

ABSTRACT Brucella abortus RB51 is a stable rough, attenuated mutant vaccine strain derived from the virulent strain 2308. Recently, we demonstrated that the wboA gene in RB51 is disrupted by an IS711 element (R. Vemulapalli, J. R. McQuiston, G. G. Schurig, N. Srirauganathan, S. M. Halling, and S. M. Boyle, Clin. Diagn. Lab. Immunol. 6:760–764, 1999). Disruption of the wboA gene in smooth, virulent B. abortus, Brucella melitensis, and Brucella suis results in rough, attenuated mutants which fail to produce the O polysaccharide (O antigen). In this study, we explored whether the wboA gene disruption is responsible for the rough phenotype of RB51. We complemented RB51 with a functionalwboA gene, and the resulting strain was designated RB51WboA. Colony and Western blot analyses indicated that RB51WboA expressed the O antigen; immunoelectron microscopy revealed that the O antigen was present in the cytoplasm. Crystal violet staining, acryflavin agglutination, and polymyxin B sensitivity studies indicated that RB51WboA had rough phenotypic characteristics similar to those of RB51. Bacterial clearance studies of BALB/c mice indicated no increase in the survival ability of RB51WboA in vivo compared to that of RB51. Vaccination of mice with live RB51WboA induced antibodies to the O antigen which were predominantly of the immunoglobulin G2a (IgG2a) and IgG3 isotypes. After in vitro stimulation of splenocytes with killed bacterial cells, quantitation of gamma interferon in the culture supernatants indicated that RB51WboA immunization induced higher levels of gamma interferon than immunization with RB51. Mice vaccinated with RB51WboA were better protected against a challenge infection with the virulent strain 2308 than those vaccinated with RB51. These studies indicate that in addition to the disruption of the wboAgene there is at least one other mutation in RB51 responsible for its rough phenotype. These studies also suggest that the expressed O antigen in RB51WboA is responsible either directly or indirectly for the observed enhancement in the T-cell response.

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