Biology Immunity NUMS 2023
PMDC Verified Question 72 of 99
Which may not be a mode of action of an antibody:
A
Neutralizing an antigen
B
Precipitating an antigen
C
Secretion of cytokines
D
Enhancing phagocytosis
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Secretion of cytokines
Concept:

Antibodies are highly specialized Y-shaped proteins, not living cells, meaning they operate strictly through chemical binding mechanics.

Formula:

None

Solution:

  • Antibodies bind to antigens to neutralize them (blocking viral entry), precipitate them (clumping soluble antigens), and opsonize them (enhancing phagocytosis by macrophages).


  • However, secretion of cytokines requires a living cell with a nucleus, ribosomes, and a Golgi apparatus (like a T-cell or Macrophage).


  • An antibody is merely a secreted protein molecule and has no biological machinery to secrete anything itself.


Why other options are incorrect:

  • Neutralization, precipitation, and opsonization are the three classic textbook mechanisms of antibody action.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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