What type of cells are produced through clonal selection?

• A. Effector and Memory cells
• B. T and B cells
• C. Helper and Cytotoxic cells
• D. Plasma and Dendritic cells

Answer: (A)

Clonal selection is a critical mechanism in the adaptive immune response that explains how a specific lymphocyte, once activated by an antigen, proliferates and differentiates into various types of cells. This process primarily leads to the formation of effector cells and memory cells.

When an antigen binds to a specific B or T lymphocyte, it triggers the activation of that particular cell. Through clonal selection, this activated cell undergoes rapid division, producing a large number of clones. Some of these clones differentiate into effector cells, which actively respond to eliminate the pathogen (for example, antibody-secreting plasma cells or cytotoxic T cells). Others become memory cells, which persist long-term and are ready to mount a stronger, quicker response if the same antigen is encountered again.

This dual outcome of producing both effector and memory cells is essential for developing immunity. The presence of memory cells allows the body to "remember" past infections, leading to a more robust and efficient response upon re-exposure to the same pathogen.

While other options mention different types of immune cells involved in the response, they do not fully encompass the outcome of clonal selection, which specifically results in the generation of effector and memory cells.