Single-chain variable fragment (scFv) targeting streptolysin O controls group A Streptococcus infection

2021 ◽  
Vol 566 ◽  
pp. 177-183
Author(s):  
Chihiro Aikawa ◽  
Kiyosumi Kawashima ◽  
Chihiro Fukuzaki ◽  
Makoto Nakakido ◽  
Kazunori Murase ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Single Chain Variable Fragment ◽  
Single Chain ◽  
Streptolysin O ◽  
Group A

scholarly journals A Response Regulator That Represses Transcription of Several Virulence Operons in the Group A Streptococcus

1999 ◽  
Vol 181 (12) ◽  
pp. 3649-3657 ◽  
Author(s):  
Michael J. Federle ◽  
Kevin S. McIver ◽  
June R. Scott
Keyword(s):  
Group A Streptococcus ◽  
Response Regulator ◽  
Regulatory System ◽  
Insertion Mutant ◽  
Multiple Gene ◽  
Streptolysin S ◽  
Streptolysin O ◽  
Group A ◽  
Complement C5a ◽  
Global Regulatory System

ABSTRACT A search for homologs of the Bacillus subtilis PhoP response regulator in the group A streptococcus (GAS) genome revealed three good candidates. Inactivation of one of these, recently identified as csrR (J. C. Levin and M. R. Wessels, Mol. Microbiol. 30:209–219, 1998), caused the strain to produce mucoid colonies and to increase transcription ofhasA, the first gene in the operon for capsule synthesis. We report here that a nonpolar insertion in this gene also increased transcription of ska (encoding streptokinase),sagA (streptolysin S), and speMF (mitogenic factor) but did not affect transcription of slo(streptolysin O), mga (multiple gene regulator of GAS),emm (M protein), scpA (complement C5a peptidase), or speB or speC (pyrogenic exotoxins B and C). The amounts of streptokinase, streptolysin S, and capsule paralleled the levels of transcription of their genes in all cases. Because CsrR represses genes unrelated to those for capsule synthesis, and because CsrA-CsrB is a global regulatory system inEscherichia coli whose mechanism is unrelated to that of these genes in GAS, the locus has been renamed covR, for “control of virulence genes” in GAS. Transcription of thecovR operon was also increased in the nonpolar insertion mutant, indicating that CovR represses its own synthesis as well. All phenotypes of the covR nonpolar insertion mutant were complemented by the covR gene on a plasmid. CovR acts on operons expressed both in exponential and in stationary phase, demonstrating that the CovR-CovS pathway is separate from growth phase-dependent regulation in GAS. Therefore, CovR is the first multiple-gene repressor of virulence factors described for this important human pathogen.

scholarly journals Streptolysin O Rapidly Impairs Neutrophil Oxidative Burst and Antibacterial Responses to Group A Streptococcus

2015 ◽  
Vol 6 ◽  
Author(s):  
Satoshi Uchiyama ◽  
Simon Döhrmann ◽  
Anjuli M. Timmer ◽  
Neha Dixit ◽  
Mariam Ghochani ◽  
...  
Keyword(s):  
Oxidative Burst ◽  
Group A Streptococcus ◽  
Streptolysin O ◽  
Group A ◽  
Neutrophil Oxidative Burst

scholarly journals Streptolysin O Inhibits Clathrin-Dependent Internalization of Group A Streptococcus

mBio ◽  
2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Lauren K. Logsdon ◽  
Anders P. Håkansson ◽  
Guadalupe Cortés ◽  
Michael R. Wessels
Keyword(s):  
Epithelial Cells ◽  
Group A Streptococcus ◽  
Bacterial Species ◽  
Expression System ◽  
Human Keratinocytes ◽  
Host Cells ◽  
Local Perturbation ◽  
Lysosomal Degradation ◽  
Streptolysin O ◽  
Group A

ABSTRACTGroup AStreptococcus(GAS) can be internalized by epithelial cells, including keratinocytes from human skin or pharyngeal epithelium. Internalization of GAS by epithelial cells has been postulated both to play a role in host defense and to provide a sanctuary site for GAS survival. The cholesterol-binding cytolysin streptolysin O (SLO) appears to enhance virulence in part by inhibiting GAS internalization by human keratinocytes and by disrupting the lysosomal degradation of internalized GAS. We now report that low-level production of SLO by an inducible expression system reduced GAS internalization by keratinocytes. Induced SLO expression also prevented lysosomal colocalization with intracellular bacteria and acidification of GAS-containing vacuoles. Exogenous recombinant SLO mimicked the inhibitory effect of SLO secretion on GAS entry but not that on colocalization with the lysosomal marker LAMP-1, implying that disruption of lysosomal degradation requires intracellular secretion of SLO. The internalization of SLO-negative GAS was blocked by the depletion of host cell cholesterol and by the inhibition or knocking down of the expression of clathrin or dynamin. SLO also inhibited the cellular uptake of other cargos that are internalized by clathrin-mediated uptake or by macropinocytosis. We conclude that SLO interferes with the internalization of GAS through local perturbation of the keratinocyte cell membrane and disruption of a clathrin-dependent uptake pathway.IMPORTANCEStreptolysin O (SLO) is a member of a family of pore-forming toxins, the cholesterol-dependent cytolysins, that are produced by many Gram-positive bacterial pathogens. While SLO can lyse host cells at high doses, much smaller amounts appear to contribute to pathogenesis by inhibiting the internalization of group AStreptococcus(GAS) by pharyngeal keratinocytes and by preventing efficient intracellular killing by lysosomal fusion. This study provides evidence that SLO blocks a clathrin-dependent pathway for the internalization of GAS through effects on the cell surface, whereas inhibition of lysosomal fusion depends on the intracellular production of SLO. These observations may have broader implications for understanding the pathogenesis of multiple bacterial species that produce cholesterol-dependent cytolysins.

scholarly journals Effect of Phosphatase Activity of the Control of Virulence Sensor (CovS) on Clindamycin-Mediated Streptolysin O Production in Group A Streptococcus

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Chuan Chiang-Ni ◽  
Huei-Chuan Tseng ◽  
Yong-An Shi ◽  
Cheng-Hsun Chiu
Keyword(s):  
Phosphatase Activity ◽  
Group A Streptococcus ◽  
Response Regulator ◽  
Protein Synthesis Inhibitor ◽  
Dependent Manner ◽  
Tissue Destruction ◽  
Synthesis Inhibitor ◽  
Content Type ◽  
Streptolysin O ◽  
Group A

ABSTRACT Severe manifestations of group A Streptococcus (GAS) infections are associated with massive tissue destruction and high mortality. Clindamycin (CLI), a bacterial protein synthesis inhibitor, is recommended for treating patients with severe invasive GAS infection. Nonetheless, the subinhibitory concentration of CLI induces the production of GAS virulent exoproteins, such as streptolysin O (SLO) and NADase, which would enhance bacterial virulence and invasiveness. A better understanding of the molecular mechanism of how CLI triggers GAS virulence factor expression will be critical to develop appropriate therapeutic approaches. The present study shows that CLI activates SLO and NADase expressions in the emm1-type CLI-susceptible wild-type strain but not in covS or control of virulence sensor (CovS) phosphatase-inactivated mutants. Supplementation with Mg2+, which is a CovS phosphatase inhibitor, inhibits the CLI-mediated SLO upregulation in a dose-dependent manner in CLI-susceptible and CLI-resistant strains. These results not only reveal that the phosphorylation of response regulator CovR is essential for responding to CLI stimuli, but also suggest that inhibiting the phosphatase activity of CovS could be a potential strategy for the treatment of invasive GAS infection with CLI.

scholarly journals Streptolysin O Induces the Ubiquitination and Degradation of Pro-IL-1β

2019 ◽  
Vol 11 (6) ◽  
pp. 457-468 ◽  
Author(s):  
Dóra Hancz ◽  
Elsa Westerlund ◽  
Christine Valfridsson ◽  
Getachew Melkamu Aemero ◽  
Benedicte Bastiat-Sempe ◽  
...  
Keyword(s):  
Pore Formation ◽  
Group A Streptococcus ◽  
Bacterial Virulence ◽  
Infection Model ◽  
Inflammasome Activation ◽  
Human Pathogen ◽  
Macrophage Infection ◽  
Streptolysin O ◽  
Group A ◽  
The Many

Group A Streptococcus (GAS) is a common and versatile human pathogen causing a variety of diseases. One of the many virulence factors of GAS is the secreted pore-forming cytotoxin streptolysin O (SLO), which has been ascribed multiple properties, including inflammasome activation leading to release of the potent inflammatory cytokine IL-1β from infected macrophages. IL-1β is synthesized as an inactive pro-form, which is activated intracellularly through proteolytic cleavage. Here, we use a macrophage infection model to show that SLO specifically induces ubiquitination and degradation of pro-IL-1β. Ubiquitination was dependent on SLO being released from the infecting bacterium, and pore formation by SLO was required but not sufficient for the induction of ubiquitination. Our data provide evidence for a novel SLO-mediated mechanism of immune regulation, emphasizing the importance of this pore-forming toxin in bacterial virulence and pathogenesis.

scholarly journals THE USE OF PRECIPITIN ANALYSIS IN AGAR FOR THE STUDY OF HUMAN STREPTOCOCCAL INFECTIONS

1958 ◽  
Vol 108 (3) ◽  
pp. 385-410 ◽  
Author(s):  
Seymour P. Halbert
Keyword(s):  
Gamma Globulin ◽  
Group A Streptococcus ◽  
Streptococcal Infections ◽  
High Potency ◽  
Streptolysin O ◽  
Combined Use ◽  
Group A ◽  
Human Gamma Globulin ◽  
Human Infections

As evidenced by precipitin analysis with pooled human gamma globulin, at least 12 distinct antigens were produced in cultures by one strain of Group A streptococcus (C203S). It was suggested on this basis, that these antigens were produced in vivo during human infections. By the combined use of continuous flow electrophoresis on paper curtains, and column chromatography with calcium phosphate gels, five of these have been isolated in a probable high state of purity. One of the components was obtained from culture filtrates of a Group C streptococcal strain. Three of the purified antigens have been tentatively identified as streptolysin "O", diphosphopyridinenucleotidase, and proteinase precursor. The latter could be very readily crystallized, and appears "identical" with that described by Elliott. The DPNase was of extremely high potency, 1 mg. being capable of destroying 12.6 gm. of DPN in 7½ minutes at 37°C. The identity of the other two components is uncertain as yet. They are distinct from each other and the above products immunologically, and are not related to the "C" carbohydrate. The applicability of these methods for the analysis of infectious diseases generally was discussed.

scholarly journals Rational Design of a Glycoconjugate Vaccine against Group A Streptococcus

2020 ◽  
Vol 21 (22) ◽  
pp. 8558
Author(s):  
Roberta Di Benedetto ◽  
Francesca Mancini ◽  
Martina Carducci ◽  
Gianmarco Gasperini ◽  
Danilo Gomes Moriel ◽  
...  
Keyword(s):  
Rational Design ◽  
Negative Impact ◽  
Group A Streptococcus ◽  
Protein Antigens ◽  
Hemolysis Assay ◽  
Middle Income ◽  
Middle Income Countries ◽  
Streptolysin O ◽  
Group A ◽  
Improved Design

No commercial vaccine is yet available against Group A Streptococcus (GAS), major cause of pharyngitis and impetigo, with a high frequency of serious sequelae in low- and middle-income countries. Group A Carbohydrate (GAC), conjugated to an appropriate carrier protein, has been proposed as an attractive vaccine candidate. Here, we explored the possibility to use GAS Streptolysin O (SLO), SpyCEP and SpyAD protein antigens with dual role of antigen and carrier, to enhance the efficacy of the final vaccine and reduce its complexity. All protein antigens resulted good carrier for GAC, inducing similar anti-GAC IgG response to the more traditional CRM197 conjugate in mice. However, conjugation to the polysaccharide had a negative impact on the anti-protein responses, especially in terms of functionality as evaluated by an IL-8 cleavage assay for SpyCEP and a hemolysis assay for SLO. After selecting CRM197 as carrier, optimal conditions for its conjugation to GAC were identified through a Design of Experiment approach, improving process robustness and yield This work supports the development of a vaccine against GAS and shows how novel statistical tools and recent advancements in the field of conjugation can lead to improved design of glycoconjugate vaccines.

Sign in / Sign up

Export Citation Format

Share Document