Final answer:
The statement is correctly completed by option 2: B-cells, antigen, plasma cells. B-cells, once activated by an antigen, differentiate into plasma cells that produce and secrete antibodies.
Step-by-step explanation:
The correct option that completes the given statement about the differentiation of B-cells is (2) B-cells, antigen, plasma cells.
B-cells are activated by binding to an antigen, which then induces these cells to differentiate into plasma cells. These plasma cells act as antibody factories, secreting large volumes of antibodies into the bloodstream, which are critical for fighting off infections. These antibodies retain the same antigen specificity as the B-cell receptors (BCRs) from their parent B cell.
Upon encountering an antigen, a B cell processes and presents this antigen to helper T cells. Subsequently, the helper T cells release cytokines that further stimulate the B cell to proliferate and mature into plasma cells and memory B cells. Plasma cells, therefore, are the effector cells that produce antibodies as part of the body's adaptive immune response.