Final answer:
Through clonal expansion, both plasma cells and memory B cells are produced. Plasma cells secrete antibodies, while memory B cells enable a quicker secondary response upon re-exposure to the antigen.
Step-by-step explanation:
Clonal expansion refers to the process by which activated B cells proliferate and differentiate. As a result of clonal expansion, two primary cell types are produced: plasma cells and memory B cells. Plasma cells function as antibody factories, secreting large quantities of antibodies specifically tuned to the antigen that triggered the response. These antibodies are essential for what is known as humoral immunity, defending the body against pathogens in body fluids. On the other hand, memory B cells retain information about the pathogen, enabling the immune system to mount a quicker and more robust response upon subsequent encounters with the same pathogen.
During a primary response, antibody production is initially delayed and the levels produced are lower; it's enough for protection but not as vigorous as subsequent responses. When the same antigen is encountered again, the existing memory B cells enable the immune system to have a faster, secondary response without the initial delay and with a significantly higher production of antibodies.