Final answer:
The primary immune response is the body's first exposure to a pathogen with a slower buildup of antibodies, whereas the secondary immune response is faster and stronger due to memory B cells from the primary exposure, leading to higher antibody levels and often symptomless pathogen elimination.
Step-by-step explanation:
The difference between primary and secondary immune responses lies in their speed and intensity. Primary immune response is the body's initial reaction to a pathogen, where B cell clones expand and differentiate into plasma cells. This response is slower because it is the first exposure to the antigen, taking several days to produce antibody levels sufficient for immune protection. During this response, memory B cells are also created.
The secondary immune response occurs when the body encounters the same antigen again. It is more rapid and produces a higher antibody concentration due to the presence of memory B cells from the primary exposure. The lag period is shorter, antibody production is significantly higher, and the antibodies are more effective. This leads to a quicker pathogen elimination, often without any symptoms.
In summary, the primary immune response is slower and produces fewer antibodies, whereas the secondary immune response is more rapid, resulting in higher and more effective antibody levels due to the activation of memory B cells, providing better immune protection.