Difference Between Endotoxin and Exotoxin
An Overview of Toxins: Examine the Features of Endotoxins and Exotoxins.
In order to understand the difference between endotoxin and exotoxin, one must be aware of toxins and their types.
Meaning of Toxin
A chemical agent that can harm an organism is a toxin. An ion or an atom that negatively affects a cell could be viewed as poison. Poison also comes in the form of complex molecules, like proteins in snake venom. However, other atoms and substances release radiation, which kills living things.
Effect of Toxins
Toxin have a wide range of a impacts on various creatures, depending on the toxin. Since the most potent toxins damage various cell types in an organism, their ultimate consequence is death. Toxins injure cells in various ways, depending on how they are affected.
Types of Toxins
A toxin can vary significantly in size and shape. It might be a charged particle moving erratically through an organism, affecting various responses, or specialised proteins that specifically attack the nervous system of a target species. Defining their size and form is challenging because “toxin” encompasses a wide range of substances. Animals frequently use the toxins they produce to subdue their prey or defend themselves from threats. They are therefore developed to especially affect some species. For example, snake venom is a form of biological toxin composed of a mixture of various proteins.
What is Endotoxin and Exotoxin?
Endotoxin: Endotoxins are potently toxic complex substances which are mainly secreted by Gram-negative bacteria. were first discovered in the late 19th century. Endotoxins, also known as lipopolysaccharides (LPS), are one of the most common pyrogens (substances with the capability to induce fever).They belong to the outer membrane of Gram-negative bacteria and are composed of a hydrophilic polysaccharide and a hydrophobic entity called Lipid A.
Structure of Endotoxin
Endotoxins, as mentioned earlier, consist of a polysaccharide linked to lipid A (a lipid component). Here, lipid A is in charge of the compound’s hazardous side effects. Endotoxins exhibit different structural features among various Gram-negative bacteria. As a result, the structure of the endotoxin influences its level of toxicity.
Exotoxin: Both Gram-negative and Gram-positive bacteria can release poisons known as exotoxins. They are highly potent and, among other things, can disrupt normal biological processes to severely damage host cells. Exotoxins can or cannot be proteins depending on the bacterium involved. Like many other chemical species, these toxins (like botulinum neurotoxins) are synthesized in the cytoplasm of the bacterium before its release into the extracellular environment. Some of the pathogens can also be found as intracellular pathogens inside the host cells. The toxins are therefore promptly released into the host cells.
Structure of Exotoxin
Exotoxins are primarily composed of proteins and are produced during the exponential growth phase. Diffusible and soluble proteins make up exotoxins. Exotoxins have a significantly different molecular structure than endotoxins. Exotoxins exist in multiple forms, and many more have yet to be discovered.
Endotoxin and Exotoxin Difference
| S.No |
Category |
Endotoxin |
Exotoxin |
|
1 |
Definition |
Makes up part of the cell wall and is released upon the death of bacteria. | Is released as a results of metabolic processe. |
|
2 |
Immune response |
Somewhat less effective at triggering an immune response. |
The has a greater capacity to a stimulate the immune systems. |
|
3 |
Constituents |
Composed of a combination of lipo glycans. | Contains polypeptides |
|
4 |
Enzyme response |
It doesn’t engage in any enzymatic processes. | Enzymatic processes dominate most of the activity. |
|
5 |
Toxoids |
Unable to be transformed into toxoids. | Can be transformed into toxoids. |
|
6 |
Diseases |
Infections of the urinary tract
Cardiovascular disease Meningitis caused by bacteria |
Scarlet fever
Botulism Scalded skin syndrome |
|
7 |
Examples |
Salmonella typhi (Typhoid),
Vibrio cholerae (Cholera). Streptococcus pneumoniae (sepsis ) |
Clostridium botulinum (Botox),
Clostridium tetani (Tetanus), Corynebacterium diphtheriae (Diphtheria). |
Summary
Endotoxin are made largely of lipopolysaccharide molecule, whereas exotoxins are predominantly polypeptide. When comparing exotoxins to endotoxins, exotoxins are significantly more antigenic. Exotoxins have more receptor selectivity than endotoxins. Endotoxins lack enzymatic activity, but exotoxins do. The term toxoid refers to toxins that have been inactivated (rendered non-toxic). Toxoids can be produced from exotoxins but not from endotoxins. These toxins are mainly used as vaccines because they are modified (not natively produced by the bacterium) compared with exotoxins.This is due to the fact that they can act as exotoxins and elicit an immunological response while being harmless.
