Final answer:
The activation of B lymphocytes results in the production of antibodies, which are critical in combating extracellular pathogens and are central to the humoral immunity of the adaptive immune system.
Step-by-step explanation:
The result of activation for B lymphocytes in the adaptive immune system is the production of antibodies. B cells, after maturing in the bone marrow, become capable of producing antibodies, which are crucial for the body's defense against extracellular pathogens and toxins. When a B cell encounters and engulfs an antigen, it displays fragments of the antigen on its surface, which attracts a helper T cell. With signals from the helper T cell, in the form of cytokines, the B cell becomes a plasma cell and begins to actively secrete antibodies tailored to the antigens they encountered. This process is central to humoral immunity.
It is important to note that while plasma B cells can release some cytokines, their main role is to produce antibodies, and they do not engage in phagocytosis of pathogens, which is the role of other immune cells.