Difference between Exotoxin and Endotoxin




Difference between Exotoxin and Endotoxin

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Point of distinction

Exotoxin

Endotoxin

1. Production It is released out of living bacterial cell It is a component of bacterial cell wall
2. Chemical composition Protein in nature Lipopolysaccharide
3. Molecular weight 10Kda 50-1000KDa
4. Location of toxin producing gene Plasmid or phage DNA Chromosomal DNA
5. On Heat treatment Heat labile Heat stable. It can withstand temperature of autoclave
6. On Formaldehyde treatment It form toxoid when treated with formaldehyde, which can be used as vaccine. It does not form toxoid.
7. Toxicity More toxic Less toxic
8. Lethal dose low High
9. Immunogenicity Highly immunogenic, induce production of neutralizing antibodies Poorly immunogenic
10. Mechanism of action Different exotoxin have different mechanism of action. Eg. Some are neurotoxic, some are cytotoxic, some are enterotoxic etc All endotoxin have similar mechanism of action. It includes pyrogenicity, blood change and shock
11. Pyrogenicity (induce fever) Not pyrogenic Pyrogenic
12. Produced by Gram positive bacteria ( streptococcus pyogens, Staphylococcus aureus, Bacillus, Costridium tetani) and certain Gram negative bacteria Gram negative cell wall composition ( E. coli, Salmonella, Shigella)
13. Diseases caused Tetanus, Diphtheria, Botulism Sepsis, bacteremia,

Difference between Exotoxin and Endotoxin