Stability of streptococcal serum opacity factor, an HDL-disrupting protein

2017 ◽  
Vol 263 ◽  
pp. e218
Author(s):  
Corina Rosales ◽  
Dedipya Yelamanchili ◽  
Baiba Gillard ◽  
Antonio Gotto ◽  
Henry Pownall
Keyword(s):  
Serum Opacity Factor

scholarly journals Genetic characterization of Streptococcus pyogenes emm 89 strains isolated in Japan from 2011 to 2019

2020 ◽  
Author(s):  
Yujiro Hirose ◽  
Masaya Yamaguchi ◽  
Norihiko Takemoto ◽  
Tohru Miyoshi-Akiyama ◽  
Tomoko Sumitomo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Genetic Characterization ◽  
Streptococcal Toxic Shock Syndrome ◽  
Toxic Shock ◽  
Gene Encoding ◽  
Serum Opacity Factor ◽  
Genetic Features ◽  
Fibronectin Binding Protein

Streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes emm 89 strains has been increasing in several countries and reported to be linked with a recently emerged clade of emm89 strains, designated clade 3. In Japan, epidemiological and genetic information for emm89 strains remains elusive. In this study, we utilized emm89 strains isolated from both STSS (89 isolates) and non-STSS (72 isolates) infections in Japan from 2011 to 2019, and conducted whole-genome sequencing and comparative analysis, which resulted in classification of a large majority into clade 3 regardless of disease severity. In addition, STSS-associated genes and SNPs were found in clade 3 strains, including mutations of streptokinase (Ska), control of virulence sensor (CovS), serum opacity factor (SOF), sortase (SrtB), and fibronectin-binding protein F1 (PrtF1), and absence of the hylP1 gene encoding hyaluronidase. These findings provide insights into notable genetic features of emm89 strains.

Mapping the Fibrinogen-Binding Domain of Serum Opacity Factor of Group A Streptococci

2002 ◽  
Vol 44 (4) ◽  
pp. 236-240 ◽  
Author(s):  
Harry S. Courtney ◽  
James B. Dale ◽  
David L. Hasty
Keyword(s):  
Binding Domain ◽  
Group A Streptococci ◽  
Fibrinogen Binding ◽  
Serum Opacity Factor ◽  
Group A

scholarly journals Serum Opacity Factor (SOF) of Streptococcus pyogenes Evokes Antibodies That Opsonize Homologous and Heterologous SOF-Positive Serotypes of Group A Streptococci

2003 ◽  
Vol 71 (9) ◽  
pp. 5097-5103 ◽  
Author(s):  
Harry S. Courtney ◽  
David L. Hasty ◽  
James B. Dale
Keyword(s):  
Streptococcus Pyogenes ◽  
Rabbit Antiserum ◽  
M Protein ◽  
Group A Streptococci ◽  
Streptococcal Infections ◽  
Vaccine Candidates ◽  
Human Antibodies ◽  
Serum Opacity Factor ◽  
Group A

ABSTRACT Serum opacity factor (SOF) is a protein expressed by Streptococcus pyogenes that opacifies mammalian serum. SOF is also a virulence factor of S. pyogenes, but it has not been previously shown to elicit a protective immune response. Herein, we report that SOF evokes bactericidal antibodies against S. pyogenes in humans, rabbits, and mice. Rabbit antiserum against purified recombinant SOF2 opsonized SOF-positive M type 2, 4, and 28 S. pyogenes in human blood but had no effect on SOF-negative M type 5 S. pyogenes. Furthermore, affinity-purified human antibodies against SOF2 also opsonized SOF-positive streptococci. A combination of antisera against M2 and SOF2 proteins was dramatically more effective in killing streptococci than either antiserum alone, indicating that antibodies against SOF2 enhance the opsonic efficiency of M protein antibodies. Mice tolerated an intravenous injection of 100 μg of SOF without overt signs of toxicity, and immunization with SOF protected mice against challenge infections with M type 2 S. pyogenes. These data indicate that SOF evokes opsonic antibodies that may protect against infections by SOF-positive serotypes of group A streptococci and suggest that different serotypes of SOF have common epitopes that may be useful vaccine candidates to protect against group A streptococcal infections.

scholarly journals The serum opacity reaction of Streptococcus pyogenes: general properties of the streptococcal factor and of the reaction in aged serum

1968 ◽  
Vol 66 (1) ◽  
pp. 37-47 ◽  
Author(s):  
M. J. Hill ◽  
Lewis W. Wannamaker
Keyword(s):  
Streptococcus Pyogenes ◽  
Divalent Cations ◽  
Horse Serum ◽  
Sodium Deoxycholate ◽  
Heat Stability ◽  
Maximal Activity ◽  
Free Enzyme ◽  
Ph Optimum ◽  
Serum Opacity Factor ◽  
High Concentrations

SUMMARYThe capacity of certain strains of Streptococcus pyogenes to produce opacity in aged horse serum has been studied. Cells from all stages of the growth cycle are able to produce opacity. Maximal activity is reached towards the end of the exponential phase of growth.Examination of cell fractions obtained by mechanical breakage and differential centrifugation suggested that the cell-bound activity is predominantly associated with the membrane fraction. Extraction with sodium deoxycholate yields a soluble fraction of high activity.There is considerable strain variation in heat stability of the serum opacity factor. Cell-bound activity is often quite resistant to heat, whereas extracted activity is less stable.Low concentrations of divalent cations have an activating effect, whereas high concentrations inhibit the serum opacity reaction. High concentrations of uni-valent cations are without effect on the cell-free enzyme but have an activating effect on the cell-bound enzyme.For both the cell-bound and the cell-free enzyme the pH optimum was 5·8.Although sensitive to trypsin and pepsin, the serum opacity factor appears to be resistant to streptococcal proteinase. Its activity is destroyed by formaldehyde and by periodate but is unaffected by a number of reducing agents.Pre-heating of the serum or the addition of iodoacetate did not affect the serum opacity reaction. The enhanced cholesterol esterification previously described with fresh serum appears to be a secondary reaction. Even when isolated by relatively gentle methods, α-lipoprotein serves as a substrate only in the presence of crystalline serum albumin.

scholarly journals The Structure and Function of Serum Opacity Factor: A Unique Streptococcal Virulence Determinant That Targets High-Density Lipoproteins

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Harry S. Courtney ◽  
Henry J. Pownall
Keyword(s):  
Lipid Vesicles ◽  
Structure And Function ◽  
High Density ◽  
Host Cells ◽  
High Density Lipoproteins ◽  
Multifunctional Protein ◽  
Virulence Determinant ◽  
Serum Opacity Factor ◽  
Animal Pathogens ◽  
And Function

Serum opacity factor (SOF) is a virulence determinant expressed by a variety of streptococcal and staphylococcal species including both human and animal pathogens. SOF derives its name from its ability to opacify serum where it targets and disrupts the structure of high-density lipoproteins resulting in formation of large lipid vesicles that cause the serum to become cloudy. SOF is a multifunctional protein and in addition to its opacification activity, it binds to a number of host proteins that mediate adhesion of streptococci to host cells, and it plays a role in resistance to phagocytosis in human blood. This article will provide an overview of the structure and function of SOF, its role in the pathogenesis of streptococcal infections, its vaccine potential, its prevalence and distribution in bacteria, and the molecular mechanism whereby SOF opacifies serum and how an understanding of this mechanism may lead to therapies for reducing high-cholesterol concentrations in blood, a major risk factor for cardiovascular disease.

scholarly journals Molecular characterization of invasive and non-invasive Streptococcus pyogenes isolates from Romania

2008 ◽  
Vol 57 (11) ◽  
pp. 1354-1363 ◽  
Author(s):  
Bogdan Luca-Harari ◽  
Monica Straut ◽  
Silvia Cretoiu ◽  
Maria Surdeanu ◽  
Vasilica Ungureanu ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Epidemiological Data ◽  
Invasive Disease ◽  
Reference Laboratory ◽  
Non Invasive ◽  
Serum Opacity Factor ◽  
Fibronectin Binding Protein ◽  
Resistance Rates ◽  
And Control

In 2002, the Romanian National Reference Laboratory was invited to join the Strep-EURO project to study invasive Streptococcus pyogenes infections. During 2003 and 2004, a total of 33 isolates recovered from invasive disease were received from eight Romanian counties. For comparison, 102 isolates from non-invasive disease, as well as a collection of 12 old invasive strains (isolated between 1967 and 1980) were included. All isolates were characterized by several methods: T and emm typing, presence of the fibronectin-binding protein F1 gene (prtF1), serum opacity factor (sof), and superantigen (SAg) genes (speA, speB, speC, speF, speG, speH, ssa and smeZ). The recent invasive isolates exhibited 19 emm-types, of which emm1, emm81, emm76, emm49 and emm78 covered 57 % of the strains. Furthermore, multilocus sequence typing analysis revealed nine new sequence types, corresponding to emm types 1, 12, 49, 81, 92, 100, 106 and 119. The non-invasive isolates comprised 24 different emm types with a predominance of emm1 and 12; the old invasive strains were of eight emm types, of which four were unique for this group. All isolates harboured speB and speF; smeZ was detected in all invasive strains, except for the emm49 and emm81 isolates. The majority of isolates from carriers, and patients with pharyngitis were prtF1 positive, most of these (14 strains) being emm12. High tetracycline resistance rates were noted among both invasive and control isolates (54 % and 35 %, respectively), whereas macrolide resistance rates were low (3 % and 5 %, respectively). Active and continuing surveillance is required to provide an accurate assessment of the disease burden and to provide epidemiological data on the character of isolates in Romania.

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