There are two ways that toxins are released into the environment. Some cells will secrete toxins while other cells will release toxins upon cell lysis. Exotoxins are secreted by the cell while endotoxins are released upon cell lysis. Endotoxins are usually a lipopolysaccharide or a cell wall protein. There are three ways for exotoxins or endotoxins to have a toxic effect on the host:
| Name | Organism | Activity |
| Anthrax Toxin | Bacillus anthracis | Edema Factor (EF) is an adenylatecyclase that causes increased levels in intracellular cyclic AMP in phagocytes and formation of ion-permeable pores in membranes (hemolysis). |
|---|---|---|
| Adenylate cyclase toxin | Bordetella pertussis | Acts locally to increase levels of cyclic AMP in phagocytes and formation of ion-permeable pores in membranes (hemolysis). |
| Cholera enterotoxin (ctx) | Vibriocholerae | ADP ribosylation of G proteins stimulates adenlyate cyclase and increases cAMP in cells of the GI tract, causing secretion of water and electrolytes |
| E. coli LT toxin | Escherichia coli | Similar to cholera toxin |
| E. coli ST toxin | Escherichia coli | Stimulates guanylatecyclase and promotes secretion of water and electrolytes from intestinal epithelium |
| Shiga toxin | Shigelladysenteriae | Enzymatically cleaves rRNAresulting in inhibition of protein synthesis in susceptible cells |
| Perfringensentero toxin | Clostridium perfringens | Stimulates adenylate cyclase leading to increased cAMPin epithelial cells |
| Botulinum toxin | Clostridium botulinum | Zn++dependent protease that inhibits neurotransmission at neuromuscular synapses, resulting in flaccid paralysis |
| Tetanus toxin | Clostridium tetani | Zn++dependent protease that inhibits neurotransmission at inhibitory synapses resulting in spastic paralysis |
| Diphtheria toxin (dtx) | Corynebacterium diphtheriae | ADP ribosylationof elongation factor 2 leads to inhibition of protein synthesis in target cells |
| Exotoxin A | Pseudomonas aeruginosa | Inhibits protein synthesis; similar to diphtheria toxin |
| Anthrax toxin (LF) | Bacillus anthracis | Lethal Factor (LF) is a Zn++dependent protease that induces cytokine release and is cytotoxicto cells by an unknown mechanism |
| Pertussistoxin (ptx) | Bordetella pertussis | ADP ribosylationof G proteins blocks inhibition of adenylatecyclasein susceptible cells |
| Staphylococcus enterotoxins* | Staphylococcus aureus | Massive activation of the immune system, including lymphocytes and macrophages, leads to emesis |
| Toxic Shock Syndrome Toxin (TSST-1)* |
Staphylococcus aureus | Acts on the vascular system causing inflammation, fever and shock |
| Exfoliatintoxin* | Staphylococcus aureus | Cleavage of epidermal cells (intradermal separation) |
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