Diphtheria toxin’s mechanism of action
is:
September 2009
a) Inhibiting glucose synthesis
b) Inhibiting protein synthesis
c) Promoting acetylcholine release
d) Altering cyclic GMP levels
Correct Answer - B
Ans. B: Inhibiting protein synthesis
The diphtheria toxin causes the death eucaryotic cells and tissues
by inhibition of protein synthesis in the cells. Although the toxin is
responsible for the lethal symptoms of the disease, the virulence of
C. diphtheriae cannot be attributed to toxigenicity alone, since a
distinct invasive phase apparently precedes toxigenesis.