Memory B- and T-cells remain after the primary response declines. On re-exposure, immune memory supports a faster, stronger secondary response in IB Biology SL C3.2.10.
A person was infected with a pathogen and then later in life they were re-infected with the same pathogen. The graph shows the concentration of antibodies found in the blood that were produced in response to these two infections.
Time / days
What is the reason for the faster rise in antibody concentration after the second infection?
The patient had previously been vaccinated with the antibody.
Antibodies had been stored after the first exposure.
Lymphocytes rapidly reproduced to form plasma cells.
The second exposure was more infectious.