Streptococcal toxins (streptolysin O, streptolysin S, erythrogenic toxin)

Alouf, Joseph E.

doi:10.1016/0163-7258(80)90045-5

Cited by 250 publications

(187 citation statements)

References 146 publications

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“…Thiol-activated hemolysin activity is inhibited by sulfhydryl-blocking agents and oxidation because of the existence of free thiol group(s) (reduced form), which are characteristic of the active form essential for the lytic activity of thiol-activated hemolysin. These toxins lose their activity through the oxidation of thiol groups to disulfide bonds (6,17). Our results suggest that EHly has no free thiol group(s) to form the active site of the molecule, as in Vibrio vulnificus hemolysin (10).…”

mentioning

confidence: 86%

“…Beutin (1) reported that EHly affected human cultured cells, although the cell type was not specified. EHly was not lethal to mice, in contrast to the lethality of the thiol-activated hemolysin family to animals (17). The concentration of EHly used (100 µg/ml) was not lethal to mice, whereas intravenous injection of partially purified streptolysin O preparations killed mice, rats, rabbits, guinea pigs and cats (18).…”

mentioning

confidence: 92%

“…The results obtained in the assays with SH group reagents (thiols) and reducing agents differed in some features from the thiol-activated hemolysin family in which the lytic activity is enhanced by reducing agents but suppressed by oxidation (17). Thiol-activated hemolysin activity is inhibited by sulfhydryl-blocking agents and oxidation because of the existence of free thiol group(s) (reduced form), which are characteristic of the active form essential for the lytic activity of thiol-activated hemolysin.…”

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confidence: 99%

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Thiol-independent activity of a cholesterol-binding enterohemolysin produced by enteropathogenic Escherichia coli

Figueiredo

Catani

Yano

2003

Braz J Med Biol Res

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Enterohemolysin produced by Escherichia coli associated with infant diarrhea showed characteristics similar to those of thiol-activated hemolysins produced by Gram-positive bacteria, including inactivation by cholesterol, lytic activity towards eukaryotic cells and thermoinstability. However, enterohemolysin activity was not inactivated by oxidation or by SH group-blocking agents (1 mM HgCl 2 , 1 mM iodoacetic acid) and the hemolysin (100 µg/ml) was not lethal to mice, in contrast to the lethality of the thiol-activated hemolysin family to animals. Earlier reports showed that intravenous injection of partially purified streptolysin O preparations (0.2 µg) was rapidly lethal to mice. These results suggest that E. coli enterohemolysin is not a thiol-activated hemolysin, despite its ability to bind cholesterol, probably due to the absence of free thiol-group(s) that characterize the active form of the thiol-activated hemolysin molecule.

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confidence: 86%

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confidence: 92%

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confidence: 99%

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Thiol-independent activity of a cholesterol-binding enterohemolysin produced by enteropathogenic Escherichia coli

Figueiredo

Catani

Yano

2003

Braz J Med Biol Res

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“…The slo gene encodes SLO (streptolysin O), which resembles other known cytolysins (e.g. listeriolysin, pneumolysin, and anthrolysin) in terms of sequence, sensitivity to oxygen, and cholesterol binding (59,60). The other cytolysin, SLS (streptolysin S), is encoded by the sagA gene, which is unrelated to the cholesterol-binding cytolysins (60).…”

Section: Ifn-␣smentioning

confidence: 99%

Group A Streptococcus Activates Type I Interferon Production and MyD88-dependent Signaling without Involvement of TLR2, TLR4, and TLR9

Gratz

Siller

Schaljo

et al. 2008

Journal of Biological Chemistry

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Bacterial pathogens are recognized by the innate immune system through pattern recognition receptors, such as Toll-like receptors (TLRs). Engagement of TLRs triggers signaling cascades that launch innate immune responses. Activation ofMAPKs and NF-B, elements of the major signaling pathways induced by TLRs, depends in most cases on the adaptor molecule MyD88. In addition, Gram-negative or intracellular bacteria elicit MyD88-independent signaling that results in production of type I interferon (IFN). Here we show that in mouse macrophages, the activation of MyD88-dependent signaling by the extracellular Gram-positive human pathogen group A streptococcus (GAS; Streptococcus pyogenes) does not require TLR2, a receptor implicated in sensing of Gram-positive bacteria, or TLR4 and TLR9. Redundant engagement of either of these TLR molecules was excluded by using TLR2/4/9 triple-deficient macrophages. We further demonstrate that infection of macrophages by GAS causes IRF3 (interferon-regulatory factor 3)-dependent, MyD88-independent production of IFN. Surprisingly, IFN is induced also by GAS lacking slo and sagA, the genes encoding cytolysins that were shown to be required for IFN production in response to other Gram-positive bacteria. Our data indicate that (i) GAS is recognized by a MyD88-dependent receptor other than any of those typically used by bacteria, and (ii) GAS as well as GAS mutants lacking cytolysin genes induce type I IFN production by similar mechanisms as bacteria requiring cytoplasmic escape and the function of cytolysins.Group A streptococcus (GAS 4 ; Streptococcus pyogenes) is an important human Gram-positive pathogen responsible for a wide spectrum of infections, ranging from mild diseases (e.g. tonsillitis) to serious illness (e.g. necrotizing fasciitis, sepsis, or severe poststreptococcal sequelae) (1). The persistence of GAS in the human population and the severity of some GAS diseases are the result of activities of a number of virulence factors that enable the pathogen to escape immune surveillance or, on contrary, induce an overreaction of the immune system (2, 3). Although GAS is generally regarded as an extracellular pathogen, recent findings suggest that GAS can survive (although not multiply) within various host cells, such as neutrophils, macrophages, epithelial cells, and fibroblasts (4 -7). The surviving bacteria may serve as a reservoir for recurrent GAS diseases.Immune responses to bacteria are initiated by recognition of bacterial components called pathogen-associated molecular patterns through host cell-encoded pattern recognition receptors (PRRs) (8, 9). Typically, pathogen-associated molecular patterns are components of the bacterial cell wall (e.g. lipopolysaccharide and lipoteichoic acid), but they may also be derived from the inside of bacteria (e.g. DNA). The primary function of PRRs is to trigger signaling cascades that activate antimicrobial defense programs. The best studied class of PRRs is the Toll-like receptor (TLR) family, which consists of 13 transmembrane glycoprote...

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“…pyogenes (Kim & Watson, 1972;Alouf, 1980). The association between certain M types and scarlet fever remains to be explained.…”

Section: Discussionmentioning

confidence: 99%

The incidence of scarlet fever

Perks

Mayon-White

1983

J. Hyg.

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SUMMARYThis study attempted to find the incidence of scarlet fever in the Oxford region, including the proportion of patients from whom Streptococcus pyogenes could be isolated. General practitioners collected throat swabs from patients with suspected scarlet fever. The swabs were examined for viral and bacterial pathogens. Children admitted to hospital were used as controls. Twenty-five of 105 patients with suspected scarlet fever grew Str. pyogenes; M type 4 was the commonest type. The clinical diagnosis of scarlet fever was not always confirmed by throat culture. The annual incidence of scarlet fever was estimated to be 0 3 cases per 1000 per year.

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Streptococcal toxins (streptolysin O, streptolysin S, erythrogenic toxin)

Cited by 250 publications

References 146 publications

Thiol-independent activity of a cholesterol-binding enterohemolysin produced by enteropathogenic Escherichia coli

Thiol-independent activity of a cholesterol-binding enterohemolysin produced by enteropathogenic Escherichia coli

Group A Streptococcus Activates Type I Interferon Production and MyD88-dependent Signaling without Involvement of TLR2, TLR4, and TLR9

The incidence of scarlet fever

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