College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Where do antibodies primarily arise from in the immune system?

1. Bone marrow

2. Macrophages

3. Plasma cells

4. Lymph nodes

The correct answer is: Plasma cells

Antibodies primarily arise from plasma cells, which are differentiated B cells that produce and secrete antibodies in response to an antigen. The immune system includes a complex network of cells, but plasma cells play a key role in the adaptive immune response by generating high-affinity antibodies that can specifically target pathogens. When B cells encounter their specific antigen, they undergo a process of activation and differentiation. Once activated, they proliferate and differentiate into plasma cells, which are responsible for producing antibodies. These antibodies circulate in the bloodstream and bind to pathogens or any foreign substances, marking them for destruction or neutralization by other components of the immune system. While bone marrow is essential as the site of B cell maturation, and lymph nodes function as sites for immune cell interaction and activation, it is ultimately the plasma cells that are the effector cells specifically responsible for antibody production. Macrophages, on the other hand, are part of the innate immune response and serve primarily to phagocytize pathogens; they do not produce antibodies. Thus, plasma cells are the final and critical source of antibodies in the immune system's response to infection.