Endotoxins –

🔻They are Lipopolysaccharide in nature and former integral part of the gram negative bacteria cell wall.

🔻 They are Heat stable.

🔻Form integral part of the cell wall; released only on disruption of bacterial cell.

🔻Weakly antigenic; antitoxin is not formed but antibodies against polysaccharide are raised.

🔻Cannot be toxoided.

🔻No enzymatic action.

🔻Non-specific action of all endotoxins.

🔻Low potency

🔻Non-specific in action.

🔻Usually produce fever.

🔻Produced by Gram-negative bacteria.

🔻 Massive gram negative septicemia may cause a syndrome of endotoxic shock characterized by fever, leukopenia, thrombocytopenia ,profound fall of blood pressure and circulatory collapse  to death.

Exotoxins

🔻Protein (polypeptides) M.W. 10,000 to 900,000.

🔻 Heat labile (more than 60°)

🔻Actively secreted by living cells into medium.

🔻 Highly antigenic, stimulates formation of antitoxin which neutralises toxin.

🔻Converted into toxoid by formaldehyde.

🔻Enzymatic in action.

🔻Specific pharmacological effect for each exotoxin.

🔻Very high potency.

🔻Highly specific for particular tissue eg. tetanus toxin for CNS.

🔻Don’t produce fever in host.

🔻Produced mainly by Gram-positive bacteria and also by some Gram-negative bacteria.

Source- textbook of microbiology for dental students c p baveja