Question 20

Describe how previous immunisation protects against subsequent infection.

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College Answer

Providing a statement about what vaccines do followed by some detail about the
processes involved in triggering a response and the nature of that response in both
Innate immunity and acquired immunity would have achieved a good pass.
Many candidates failed to adequately describe the nature of the primary and the
secondary response to antigen exposure. The fact that previous immunisation
enabled a brisk secondary response was recognised by most candidates but that
this was largely due to the proliferation of IgG antibody producing B lymphocytes and
effector T cells was not appreciated. Many answers simply did not include sufficient
information to achieve a pass mark.
Syllabus: M2i
Recommended sources: Review of Medical Physiology, Ganong, Chp 3