What Is an Exotoxin?
Exotoxin is a type of bacterial toxin. It is a toxic substance harmful to the body that some bacteria secrete outside the bacteria during the growth and reproduction process. According to their affinity to cells and their different modes of action, they can be divided into three categories: cytotoxicity, neurotoxicity and enterotoxin. Many Gram-positive bacteria and some Gram-negative bacteria can produce exotoxin, whose main component is protein. Exotoxin is not heat-resistant, unstable, highly antigenic, and easily destroyed. However, the toxic effect is strong. Small doses can cause death of susceptible organisms, and can also selectively affect certain tissues and organs, causing special lesions. Exotoxin is also used in the manufacture of antitoxins and toxoids for the treatment and prevention of diseases.
Basic Information
- Chinese name
- Exotoxin
- Foreign name
- exotoxin
- Attributes
- A metabolite
- Category
- Secondary metabolites
- Main ingredients
- Soluble protein
Exotoxin production
- Clostridium anaerobicus, Group A hemolytic streptococcus, Staphylococcus aureus, Bacillus anthracis can produce exotoxin; some Gram-negative bacteria such as Vibrio cholerae, Escherichia coli, Pseudomonas aeruginosa, etc Can produce exotoxin. Most exotoxins are secreted extracellularly after being synthesized inside the bacteria cells, and the secretion mechanism is similar.
Characteristics of exotoxin
- All are protein
- Most exotoxin proteins are composed of two subunits, A and B. The A subunit is the toxic part of the toxin and determines its pathogenic effect. The B subunit has no pathogenic effect, is a part that mediates the binding of exotoxin molecules to host cells, and has affinity for target cells.
- 2. Selectivity
- Exotoxin has a selective effect on tissues and organs, and by binding to the receptors of specific target tissues and organs, it causes characteristic lesions directly or after entering cells.
- 3. Physical and chemical properties
- Most exotoxins are heat-resistant and unstable to chemical factors.
Exotoxin classification
- According to the different molecular mechanisms of its structure and action, it can be divided into AB toxin, proteolytic toxin, pore-forming toxin and other toxins. According to the different affinity and mode of action of bacterial exotoxin on host cells, exotoxin can be divided into three categories: neurotoxicity, cytotoxicity, and enterotoxin.
Clinical significance of exotoxin
- Exotoxin has a strong toxic effect. Small doses can cause death of susceptible organisms, and can also selectively affect certain tissues and organs, causing special lesions. Exotoxin is also used in the manufacture of antitoxins and toxoids for the treatment and prevention of diseases.