Exotoxins vs. Endotoxins

Question 1

Source of exotoxin?

Answer 1

Certain species of gram positive and gram negative bacteria

Question 2

Source of endotoxin?

Answer 2

Outer cell membrane of most gram negative bacteria

Question 3

Which are secreted from the cell?

Answer 3

Exotoxin

Question 4

Chemistry of exotoxin?

Answer 4

Polypeptide

Question 5

Chemistry of endotoxin?

Answer 5

Lipopolysaccharide (structural part of bacteria; released when lysed)

Question 6

Location of genes in exotoxin?

Answer 6

Plasmid or bacteriophage

Question 7

Location of genes in endotoxin?

Answer 7

Bacterial chromosome

Question 8

High toxicity (fatal dose on order of 1 ug)?

Answer 8

Exotoxin

Question 9

Low toxicity (fatal dose on order of hundreds of ugs)?

Answer 9

Endotoxin

Question 10

Causes fever and shock?

Answer 10

Endotoxin

Question 11

MOA of endotoxin?

Answer 11

Induces TNF and IL-1

Question 12

Antigenicity of exotoxin?

Answer 12

Induces high titer Abs called antitoxins

Question 13

Vaccine for exotoxin?

Answer 13

Toxoids

Question 14

Vaccine for endotoxin?

Answer 14

None, no toxoids formed

Question 15

Heat stability for exotoxin?

Answer 15

Destroyed rapidly at 60 C (except staph enterotoxin)

Question 16

Heat stability for endotoxin?

Answer 16

Stable at 100 C for 1 hour