Final answer:
Activated B lymphocytes differentiate into plasma cells, which are responsible for producing antibodies. They also form memory B cells, which provide long-term immunity. This differentiation is triggered by cytokines released from helper T cells upon antigen presentation by B cells.
Step-by-step explanation:
When B lymphocytes become activated, they differentiate into specific types of cells with important functions in the immune response. The primary cells they turn into are known as plasma cells and memory B cells.
The activation of B cells is a crucial part of the immune response, and it unfolds in several steps. Initially, B cells bind to an antigen, and subsequently, they internalize and present it on their surface bound to MHC II molecules. This presentation attracts a helper T cell, which binds to the B cell at the antigen site and secretes cytokines. These cytokines signal the B cell to proliferate and differentiate into plasma cells that are responsible for producing antibodies specific to the antigen.