Exotoxin

Definition

Exotoxins are potent, extracellular toxins secreted by certain bacteria that can cause significant damage to the host by disrupting normal cellular processes. Unlike endotoxins, exotoxins are proteins and can be neutralized by antibodies.

5 Must Know Facts For Your Next Test

1. Exotoxins are typically produced by gram-positive bacteria such as Staphylococcus aureus and Streptococcus pyogenes but can also be produced by some gram-negative bacteria.
2. They are highly specific in their action, meaning different exotoxins target different types of cells or cellular mechanisms.
3. Some exotoxins act at sites distant from the original site of infection, leading to systemic effects.
4. Examples of diseases caused by exotoxins include tetanus (caused by Clostridium tetani) and diphtheria (caused by Corynebacterium diphtheriae).
5. Because they are proteins, exotoxins can be inactivated by heat and chemicals, creating toxoids that can be used for vaccination.

Review Questions

Related terms

Endotoxin:

A toxin that is a structural molecule of the bacteria itself, specifically part of the outer membrane of gram-negative bacteria.

Toxin: Any substance produced by microorganisms that is harmful to other organisms when introduced into the body.

Virulence Factor: Molecules produced by pathogens like bacteria and viruses that contribute to their ability to cause disease.