What is the primary action of B-cells in the immune system?

• A. Directly attack pathogens
• B. Release toxins to kill invaders
• C. Differentiate into plasma cells that create antibodies
• D. Engulf and digest foreign particles

Answer: (C)

The primary action of B-cells in the immune system is to differentiate into plasma cells that produce antibodies. When B-cells encounter an antigen, they undergo activation and proliferation, leading to their transformation into plasma cells. These plasma cells are specialized to secrete large amounts of antibodies, which are proteins that specifically recognize and bind to antigens on pathogens such as bacteria and viruses.

Antibodies play a crucial role in the immune response by marking pathogens for destruction, neutralizing toxins, and preventing pathogens from entering or damaging host cells. This action is a key component of the adaptive immune response, allowing the body to mount a targeted attack against specific invaders.

In contrast, other options describe functions associated with different components of the immune system. While T-cells may directly attack infected cells, or mechanisms such as phagocytosis can be carried out by immune cells like macrophages, B-cells are uniquely trained for the production of antibodies, which is vital for long-term immunity and the effectiveness of vaccines.