Exotoxin vs endotoxin

Question 1

Exotoxin

• source:
• Secreted from cell: Y or N
• Chemistry
• Location of genes:
• toxicity
• clinical effects:
• MOA
• Antigenicity
• Vaccines
• Heat stability
• typical disease

Answer 1

Exotoxin

• source: certain species of G+ and G-
• Secreted from cell: Y or N
• **Chemistry: **polypeptide
• Location of genes: Plasmid or bacteriophage
• toxicity: High (fatal dose on the order of 1 ug)
• clinical effects: Various effects
• MOA: various effects
• Antigenicity: Induces high titer antibodies called anti-toxins
• Vaccines: Toxoids used as vaccines
• Heat stability: Destroyed rapidly at 60^oC (except staphyloccola enterotoxin)
• Typical disease: Tetanus, botulisum, diphtheria

Question 2

Endotoxin

• source:
• Secreted from cell: Y or N
• Chemistry
• Location of genes:
• toxicity
• clinical effects:
• MOA
• Antigenicity
• Vaccines

Answer 2

Endotoxin

• **source: **Outer membrane of G- bacteria
• Secreted from cell: Y or N
• Chemistry: LPS Lipopolysaccharide (structural part of bacteria released when lysed).
• Location of genes: Bacterial chromosome
• Toxicity: need large number of organisms
• clinical effects: Fever, shock (hypotension), DIC
• MOA: inducces TNF, IL-1, IL-6
• Antigenicity: poorly antigenic
• Vaccines: no toxoids formed and no vaccine avaliable
• Heat stability: stable at 100^oC for 1 hr
• Typical disease: Meningococcemia; sepsis by G- rods.

Question 3

Endotoxin

• define what it is
• define the clinical symptoms associated with it

Answer 3

Endotoxin

• Definition: An LPS found in outer membrane of gram negative bacteria (both cocci and rods).
• E: Edema
• N: Nitric oxide
• D: DIC/Death
• O: Outer membrane
• T: TNF-alpha
• O: O-antigen
• X; eXtremley heat stable
• I: IL-1
• N: Neutrophil chemotaxis