Endotoxins And Exotoxins

What are Endotoxins and Exotoxins?

The primary distinction between Endotoxin, enterotoxin, and exotoxin seems to be that Endotoxin seems to be a lipopolysaccharide present inside the Gram-negative bacteria’s outer surface. However, exotoxin seems to be a protein produced mainly through Gram-positive bacteria. In the meantime, enterotoxin seems to be an exotoxin that works on the intestinal areas. Moreover, although endotoxins and enterotoxins are heat resilient, exotoxins degrade quickly, around 60 degrees Celsius. Furthermore, endotoxins have mild toxins that induce a range of symptoms, whereas enterotoxins produce diarrhoea, including food poisoning. Exotoxins, on the other hand, are very poisonous and frequently lethal.

Brief on Endotoxins and Exotoxins :

Endotoxins

Fever-inducing substances are classified as pyrogens. Endotoxin seems to be a sort of pyrogen that is found in Gram-negative bacteria such as E, coli’s outer cell membrane. Lipopolysaccharide (LPS) seems to be an endotoxin. LPS is made up of fatty acids and disaccharide phosphates inside the lipid A part, core polysaccharides, and the O-antigen inside the core polysaccharides. LPS’s endotoxin action is due to such lipid A component of said molecule. While lipid A doesn’t injure cellular tissue instantly, it serves as a marker for bacteria in both humans’ and animals’ immune cells. As a result, such cells trigger a reaction designed to ward off unwanted visitors. There is no need for prior endotoxin exposure since this reaction is entirely natural. It is also possible

Additionally, this could aid to retain our good gut microbes within and limit the substantial entry of harmful bacteria from elsewhere. This response is intrinsic, so no prior exposure to Endotoxin is necessary.

An injectable medicinal item, such as vaccination and intravenous solution, would have to be sterile and devoid of microbes due to the severe implications of infections. However, the production procedure to destroy any bacteria may lead to the production of Endotoxin. If enough Endotoxin enters our circulation as well as spinal fluid, individuals can get a fever, shock, including organ damage, just like a bacterial disease or sepsis. It can potentially lead to death in severe circumstances.

Injectables and implantables, which come into contact with the bloodstream and spinal fluid, are therefore examined for cleanliness and Endotoxin. Endotoxin test ensures the quality of the products.

Exotoxins

A poison released from bacteria is described as an exotoxin. Via killing cells and altering regular cell metabolism, this exotoxin could harm a host. They’re pretty powerful and could do a lot of damage to that same host. Exotoxins are either produced or discharged upon cell lysis, comparable to endotoxins. Gram-negative pathogens could naturally produce outer sheath vesicles having lipopolysaccharide endotoxin as well as some virulence proteins inside the enclosing membrane, as well as some other toxins as intravesicular components contributing a completely undiscovered dimension to some suitable eukaryote procedure of membrane vesicle trafficking, which is also very active just at host-pathogen functionality.

They might have a local impact or even have a significant reform. Botulinum toxin, generated from Clostridium botulinum; Corynebacterium diphtheriae toxin, generated at life-threatening diphtheria symptoms; and tetanospasmin, produced from Clostridium tetani, are all well-known exotoxins. Thermal or chemical treatments can neutralise the poisonous characteristics among most exotoxins, resulting in a toxoid. These toxoids retain inherent antigenic uniqueness and could be utilised to make antitoxins and then used as immunisations in the instances of diphtheria and tetanus.

Major differences between Endotoxin and Exotoxin

Endotoxin seems to be a toxin that would be contained inside a bacterial cell and therefore is released whenever the cell deteriorates. However, enterotoxin relates to a toxin generated inside or affecting the intestines, which causes food poisoning or cholera. The exotoxin refers to a toxin discharged into the environment by just a live bacterium.

Biomolecule Classification

Endotoxin seems to be a lipopolysaccharide, whereas enterotoxin is some kind of exotoxin, both of which are proteins.

Molecular Mass

Endotoxins have a pretty molecular weight between 50-1000 kDa, enterotoxins also have a molecular weight of approximately 25-30 kDa, whereas exotoxins have a molecular weight of near 10 kDa.

Structure

Endotoxins are composed of three main components: the O antigen, O polysaccharide, the core oligosaccharide, and the lipid A. Meanwhile, enterotoxins and exotoxins are comprised of two parts: the subunit containing enzymatic activity and a B subunit that binds to specific receptors.

Generated by

Gram-negative bacteria generate endotoxins on their outer membranes, whereas Gram-positive bacteria mostly make enterotoxins and exotoxins.

Appearance

Endotoxins constitute part of such outer cell membranes, whereas enterotoxins and exotoxins release secretory substances into the environment.

Mode of action

The mode of action of endotoxins involves Tumor Necrosis Factor and Interleukin-1. On the other hand, for exotoxins, there can be various different types of modes of actions. 

Heat stability

Endotoxins are heat tolerant and relatively stable at 25 °c for about one hour. On the contrary, exotoxins are heat labile and can get destroyed at 60-80 °c , except for the Staphylococcal enterotoxin. 

Immunogenicity

Endotoxins show weak immunogenicity and don’t produce antitoxins. Exotoxins are extremely immunogenic. They stimulate the humoral immune response as a part of the innate immunity and thus lead to generation of antitoxins for neutralization of the toxin. 

Conclusion

The article briefly talks about Endotoxins and Exotoxins and their definitions with significant differences on the said topic. The article covers all the essential information on Endotoxins and Exotoxins and any further research may also help better understand the said topic.