| 11. |
- Leon-Velarde, Carlos G., et al.
(författare)
-
Yersinia enterocolitica-specific infection by bacteriophages TG1 and φR1-RT is dependent on temperature-regulated expression of the phage host receptor OmpF
- 2016
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 82:17, s. 5340-5353
-
Tidskriftsartikel (refereegranskat)abstract
- Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica. To increase our knowledge of Y. enterocolitica- specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_φR1-RT (φR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively. Their genomes comprise 262 putative coding sequences and 4 tRNA genes and share 91% overall nucleotide identity. Based on phylogenetic analyses of their whole-genome sequences and large terminase subunit protein sequences, a genus named Tg1virus within the family Myoviridae is proposed, with TG1 and φR1-RT (R1RT in the ICTV database) as member species. These bacteriophages exhibit a host range restricted to Y. enterocolitica and display lytic activity against the epidemiologically significant serotypes O:3, O:5,27, and O:9 at and below 25°C. Adsorption analyses of lipopolysaccharide (LPS) and OmpF mutants demonstrate that these phages use both the LPS inner core heptosyl residues and the outer membrane protein OmpF as phage receptors. Based on RNA sequencing and quantitative proteomics, we also demonstrate that temperature-dependent infection is due to strong repression of OmpF at 37°C. In addition, φR1-RT was shown to be able to enter into a pseudolysogenic state. Together, this work provides further insight into phage-host cell interactions by highlighting the importance of understanding underlying factors which may affect the abundance of phage host receptors on the cell surface.
|
|
| 12. |
- Nandakumar, Kutty Selva, et al.
(författare)
-
Dominant suppression of inflammation by glycan-hydrolyzed IgG [Retracted]
- 2013
-
Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110:25, s. 10252-10257
-
Tidskriftsartikel (refereegranskat)abstract
- A unique anti-inflammatory property of IgG, independent of antigen specificity, is described. IgG with modification of the heavy-chain glycan on asparagine 297 by the streptococcal enzyme endo-beta-N-acetylglucosaminidase (EndoS) induced a dominant suppression of immune complex (IC)-mediated inflammation, such as arthritis, through destabilization of local ICs by fragment crystallizable-fragment crystallizable (Fc-Fc) interactions. Small amounts (250 mu g) of EndoS-hydrolyzed IgG were sufficient to inhibit arthritis in mice and most effective during the formation of ICs in the target tissue. The presence of EndoS-hydrolyzed IgG disrupted larger IC lattice formation both in vitro and in vivo, as visualized with anti-C3b staining. Neither complement binding in vitro nor antigen-antibody binding per se was affected.
|
|
| 13. |
- Nandakumar, Kutty Selva, 1965-, et al.
(författare)
-
Streptococcal Endo-β-N-Acetylglucosaminidase Suppresses Antibody-Mediated Inflammation In Vivo
- 2018
-
Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Endo-β-N-acetylglucosaminidase (EndoS) is a family 18 glycosyl hydrolase secreted by Streptococcus pyogenes. Recombinant EndoS hydrolyzes the β-1,4-di-N-acetylchitobiose core of the N-linked complex type glycan on the asparagine 297 of the γ-chains of IgG. Here, we report that EndoS and IgG hydrolyzed by EndoS induced suppression of local immune complex (IC)-mediated arthritis. A small amount (1 µg given i.v. to a mouse) of EndoS was sufficient to inhibit IgG-mediated arthritis in mice. The presence of EndoS disturbed larger IC lattice formation both in vitro and in vivo, as visualized with anti-C3b staining. Neither complement binding in vitro nor antigen-antibody binding per se were affected. Thus, EndoS could potentially be used for treating patients with IC-mediated pathology.
|
|
| 14. |
- Säll, A., et al.
(författare)
-
Development of phage-based antibody fragment reagents for affinity enrichment of bacterial immunoglobulin G binding proteins
- 2015
-
Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 14:11, s. 4704-4713
-
Tidskriftsartikel (refereegranskat)abstract
- Disease and death caused by bacterial infections are global health problems. Effective bacterial strategies are required to promote survival and proliferation within a human host, and it is important to explore how this adaption occurs. However, the detection and quantification of bacterial virulence factors in complex biological samples are technically demanding challenges. These can be addressed by combining targeted affinity enrichment of antibodies with the sensitivity of liquid chromatography-selected reaction monitoring mass spectrometry (LC-SRM MS). However, many virulence factors have evolved properties that make specific detection by conventional antibodies difficult. We here present an antibody format that is particularly well suited for detection and analysis of immunoglobulin G (IgG)-binding virulence factors. As proof of concept, we have generated single chain fragment variable (scFv) antibodies that specifically target the IgG-binding surface proteins M1 and H of Streptococcus pyogenes. The binding ability of the developed scFv is demonstrated against both recombinant soluble protein M1 and H as well as the intact surface proteins on a wild-type S. pyogenes strain. Additionally, the capacity of the developed scFv antibodies to enrich their target proteins from both simple and complex backgrounds, thereby allowing for detection and quantification with LC-SRM MS, was demonstrated. We have established a workflow that allows for affinity enrichment of bacterial virulence factors.
|
|
| 15. |
- Vaca, Diana J, et al.
(författare)
-
Interaction with the host : the role of fibronectin and extracellular matrix proteins in the adhesion of Gram-negative bacteria
- 2020
-
Ingår i: Medical microbiology and immunology. - : Springer Science and Business Media LLC. - 0300-8584 .- 1432-1831. ; 209:3, s. 277-299
-
Forskningsöversikt (refereegranskat)abstract
- The capacity of pathogenic microorganisms to adhere to host cells and avoid clearance by the host immune system is the initial and most decisive step leading to infections. Bacteria have developed different strategies to attach to diverse host surface structures. One important strategy is the adhesion to extracellular matrix (ECM) proteins (e.g., collagen, fibronectin, laminin) that are highly abundant in connective tissue and basement membranes. Gram-negative bacteria express variable outer membrane proteins (adhesins) to attach to the host and to initiate the process of infection. Understanding the underlying molecular mechanisms of bacterial adhesion is a prerequisite for targeting this interaction by "anti-ligands" to prevent colonization or infection of the host. Future development of such "anti-ligands" (specifically interfering with bacteria-host matrix interactions) might result in the development of a new class of anti-infective drugs for the therapy of infections caused by multidrug-resistant Gram-negative bacteria. This review summarizes our current knowledge about the manifold interactions of adhesins expressed by Gram-negative bacteria with ECM proteins and the use of this information for the generation of novel therapeutic antivirulence strategies.
|
|
