Secondary Immune Response Curve

Steps:

• Recall primary exposure produces a slow antibody rise due to initial B-cell activation.
• Note second exposure triggers memory cells for faster, stronger response.
• Identify graph with quicker peak and higher concentration after re-exposure.
• Match to option showing rapid secondary rise versus primary lag.

Why A is correct:

• Depicts anamnestic response where antibodies surge faster and higher, per immunological memory definition.

Why the others are wrong:

• B: Shows only primary response with slow rise, no secondary boost.
• C: Displays flat or declining levels, ignoring memory cell activation.
• D: Illustrates prolonged low response, contradicting rapid secondary peak.

Final answer: A