The mechanism of action of the exotoxin produced by Corynebacterium diphtheriae can be characterized by which of the following?
Acting as a superantigen that binds to MHC class II protein and the T-cell receptor
Blocking the release of acetylcholine causing anticholinergic symptoms
Blocking the release of glycine
Inhibits protein synthesis EF-2 adenosine diphosphate (ADP) ribosylation.
C. diphtheriae Produces a potent exotoxin encoded by a lysogenic beta-prophage. The toxin has a mol. Wt of 61,150 daltons 2 pas; A: 21,150 & B:40,000; A: active; B: binding Following proteolytic cleavage, the A segment is released into the host cell where it inhibits protein synthesis ADP ribosylation of elongation factor/ EF-2 (which is a t RNA translocase). Inhibition of protein synthesis disrupts normal cellular physiologic functions that are believed to be responsible for the necrotizing and neurotoxic effects of diphtheria toxin.
Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli)