SBA — Single Best Answer · Review
Question 607
Immunology → General
Classification
Question
SSBAQuestion Header
Which feature most clearly distinguishes active acquired immunity from passive acquired immunity?
Question Stem
Select the single best answer.
Options
A
Protection is always immediate
B
Immunological memory is present
C
Host participation is absent
D
Protection is transient
E
A subsequent dose is less effective
Explanation
Active immunity involves participation of the host immune apparatus and produces immunological memory. Passive immunity is produced by transfer of readymade antibody, acts immediately, is transient and does not produce immunological memory.
Option Validity
A) Immediate protection characterises passive rather than active immunity.
C) Host participation occurs in active immunity; it is absent in passive immunity.
D) Transient protection is characteristic of passive immunity.
E) A subsequent dose can act as a booster in active immunity, whereas subsequent passive doses may be less effective.
Further Reading
Saxena MRCOG-1 Basic Sciences — Immunology: Innate and Acquired Immunity, printed page 209.