Is staphylococcal enterotoxin A superantigen?
Staphylococcal enterotoxin B (SEB) is a toxin produced by Staphylococcus aureus. The bacteria produce a repertoire of staphylococcal enterotoxins collectively called superantigens (SAgs) because of their inherent property to activate large amounts of T cells (1).
Which Staphylococcus aureus toxin is a superantigen?
S. aureus secretes two types of toxins with superantigen activity, enterotoxins, of which there are six antigenic types (named SE-A, B, C, D, E and G), and toxic shock syndrome toxin (TSST-1). Enterotoxins cause diarrhea and vomiting when ingested and are responsible for staphylococcal food poisoning.
What is a superantigen exotoxin?
As was learned earlier under Bacterial Pathogenicity, superantigens are type I toxins that can trigger a harmful immune response. Exotoxins are toxins, often proteins in nature, secreted from a living bacterium but also released upon bacterial lysis.
What is Staphylococcus aureus enterotoxin?
The S. aureus enterotoxins (SEs) are potent gastrointestinal exotoxins synthesized by S. aureus throughout the logarithmic phase of growth or during the transition from the exponential to the stationary phase [16,17,18,19,20].
What is superantigen A in Streptococcus pyogenes?
The globally prominent pathogen Streptococcus pyogenes secretes potent immunomodulatory proteins known as superantigens (SAgs), which engage lateral surfaces of major histocompatibility class II molecules and T-cell receptor (TCR) β-chain variable domains (Vβs).
What is superantigen A What does this antigen cause?
Superantigens (SAgs) are a class of antigens that result in excessive activation of the immune system. Specifically it causes non-specific activation of T-cells resulting in polyclonal T cell activation and massive cytokine release.
Does Streptococcus produce superantigen?
Superantigens produced by Streptococcus pyogenes have been implicated with streptococcal toxic shock syndrome (STSS). We analyzed 19 acute-phase serum samples for mitogenic activity from patients with severe streptococcal disease.
What is a superantigen in microbiology?
What does a superantigen do?
Superantigens are bacterial proteins that generate a powerful immune response by binding to Major Histocompatibility Complex class II molecules on antigen-presenting cells and T cell receptors on T cells.
What does staphylococcal enterotoxin do?
Staphylococcal enterotoxin B is one of the most potent bacterial superantigens that exerts profound toxic effects upon the immune system, leading to stimulation of cytokine release and inflammation. It is associated with food poisoning, nonmenstrual toxic shock, atopic dermatitis, asthma, and nasal polyps in humans.
What is the characteristics of Staphylococcus aureus enterotoxin?
Enterotoxins are staphylococcal virulence factors responsible for food poisonings in humans. These proteins are also isolated from cows with mastitis. In various countries, the percentage of enterotoxin-producing S. aureus strains ranges from 5 to 60%, depending on the enterotoxine type.
What is the superantigen produced by the Streptococcus pyogenes What does this antigen cause?