Final answer:
B cells are activated to make antibodies primarily through antigen engulfment and helper T cell signaling or via reactivation of memory B cells in a secondary immune response resulting in affinity maturation.
Step-by-step explanation:
Activation of B Cells to Make Antibodies
There are two main ways to activate a B cell so that it can produce antibodies. The first method involves the B cell encountering and engulfing its matching antigen. After processing, the B cell then presents fragments of the antigen on its surface using molecules called MHC II. This presentation attracts a helper T cell, which binds to the B cell at the antigen site and releases cytokines. These cytokines act as signals compelling the B cell to transform into a plasma cell that can produce antibodies.
The second mode of activation occurs during a secondary immune response. Here, memory B cells, constituted from a prior activation, are engaged. Upon re-exposure to the same antigen, these memory B cells quickly reproduce and mature into plasma cells that can make high-affinity IgG antibodies. This is due to a process called affinity maturation, which enhances the ability of the antibodies to bind to antigens more efficiently.
The overall goal of B cell activation is to generate a robust immune response with the production of specific antibodies that can effectively target and neutralize pathogens. This is a critical aspect of the body's adaptive immune system and is essential for protecting us from recurrent infections.