Endotoxin

Question 1

Characterization

Answer 1

• LPS of the G- cell wall : Lipid A
• Heat stable
• They are less potent and less specific in their actions compared to oxotoxins, since they do not act enzymatically
  LPS activates the complement by the alternative pathway
• Lipid A: usually released during lysis of the cell
• Endotoxin cannot be comverted to toxoids
• The endotoxin will have a large range of systemic effects:
• Fever
• Hypotension
• DIC
• Tumor necrosis
• Shock
• Lethality

Question 2

Mode of action

Answer 2

• LPS binds to LPS-binding protein in the serum –> CD14 and TLR-4 binding –> overproduction of inflamamtory mediators by macrophages and endothelial cells (IL-1, IL-8, TNF-a) –> endotoxic shock