Differences between Exotoxins and Endotoxins
| S.N. | Exotoxins | Endotoxins |
| 1 | Excreted by organisms, living cell | Integral part of cell wall |
| 2 | Found in both Gram positive and Gram Negative bacteria | Found mostly in Gram Negative Bacteria |
| 3 | It is polypeptide | It is lipopolysaccharide complex. |
| 4 | Relatively unstable, heat labile (60°C) | Relatively stable, heat tolerant |
| 5 | Highly antigenic | Weakly immunogenic |
| 6 | Toxoids can be made by treating with formalin | Toxoids cannot be made |
| 7 | Highly toxic, fatal in µg quantities | Moderately toxic |
| 8 | Usually binds to specific receptors | Specific receptors not found |
| 9 | Not pyrogenic usually, Toxin Specific | Fever by induction of interleukin 1 (IL-1) production, Shock |
| 10 | Located on extrachromosomal genes (e.g. plasmids) | Located on chromosomal genes |
| 11 | Filterable | Not so |
| 12 | It has mostly enzymatic activity | It has no enzymatic activity |
| 13 | Its molecular weight is 10KDa | Its molecular weight is 50-1000KDa |
| 14 | On boiling it get denatured. | On boiling it cannot be denatured. |
| 15 | Detected by many tests (neutralization, precipitation, etc) | Detected by Limulus lysate assay |
| 16 | Examples: Toxins produced by Bacillus cereus, Streptococcus pyogenes, Bacillus anthrcis(Alpha-toxin, also known as alpha-hemolysin (Hla)) | Examples: Toxins produced by E.coli, Salmonella Typhi, Shigella, Vibrio cholera(Cholera toxin- also known as choleragen) |
| 17 | Diseases: Tetanus, diphtheria, botulism | Diseases: Meningococcemia, sepsis by gram negative rods |
Exam Important
- Exotoxins can be toxoided.
- Exotoxins are protein in nature, heat labile and has antigenic property.
- Exotoxin has mostly enzymatic activity
- Endotoxin is lipopolysaccharide complex.
- Endotoxin has no enzymatic activity
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