FA Exotoxins and Endotoxins

Question 1

What is the source of exotoxin

Answer 1

Certain species of some gram-positive and gram-negative bacteria.

Question 2

What is the source of endotoxin

Answer 2

Outer cell membrane of most gram negative bacteria

Question 3

Is exotoxin secreted from cell?

Answer 3

Yes!

Question 4

Is endotoxin secreted from cell

Answer 4

No!

Question 5

What is the chemistry of exotoxin?

Answer 5

Polypeptide

Question 6

What is the chemistry of endotoxin?

Answer 6

Lipopolysaccharide (structural part of bacteria; released when lysed)

Question 7

What is the location of exotoxin genes?

Answer 7

Plasmid or bacteriophage

Question 8

What is the location of endotoxin genes?

Answer 8

Bacterial chromosome

Question 9

What is the toxicity of exotoxin?

Answer 9

High! (fatal dose on the order of 1 microgram)

Question 10

What is the toxicity of endotoxin?

Answer 10

Low (fatal dose on the order of hundreds of micrograms)

Question 11

What are the clinical effects of endotoxin?

Answer 11

Fever, shock

Question 12

What is the mode of action of endotoxin?

Answer 12

Induces TNF and IL-1

Question 13

What is the antigenicity of exotoxin?

Answer 13

Induces high-titer antibodies called antitoxins

Question 14

What is the antigenicity of endotoxin?

Answer 14

Poorly antigenic

Question 15

Are there vaccines against exotoxins?

Answer 15

Toxoids used as vaccines

Question 16

Are there vaccines against endotoxins?

Answer 16

No toxoids formed and no vaccine available

Question 17

What is the heat stability of exotoxins?

Answer 17

Destroyed rapidly at 60 degrees Celsius, except staph enterotoxin

Question 18

What is the heat stability of endotoxin?

Answer 18

Stable at 100 degrees C for 1 hour

Question 19

What are the typical diseases you associate with exotoxin? (Name three)

Answer 19

Tetanus, botulism, diphtheria

Question 20

What are the typical diseases you associate with endotoxin? (Name two)

Answer 20

Meningococcemia

Sepsis by gram negative rods