Microbiology Practice Exam

What is the purpose of clonal selection in the immune response?

1. The activation of T-cells by cytokines

2. The activation of B-cells by an antigen

3. The production of memory cells

4. The destruction of pathogens

The correct answer is: The activation of B-cells by an antigen

Clonal selection is a fundamental process in the adaptive immune response that specifically relates to how B-cells and T-cells recognize and respond to antigens. The process begins when a B-cell encounters an antigen that specifically fits its surface receptor. Each B-cell is programmed to recognize a unique epitope, which is a specific part of an antigen. When the correct B-cell binds to its corresponding antigen, it undergoes clonal selection. This selected B-cell is activated and begins to proliferate, producing a large number of identical cells, or clones, that also recognize the same antigen. This proliferation leads to the differentiation of some of these B-cells into plasma cells that secrete antibodies aimed at neutralizing the antigen. Clonal selection not only results in the immediate activation and response against the pathogens but also contributes to immunological memory. Some of the activated B-cells become memory cells, which persist long after the original infection has been cleared. These memory cells enable a faster and more robust response upon subsequent exposures to the same antigen. While other processes in the immune response, such as the activation of T-cells, the destruction of pathogens, and the formation of memory cells, are related to the immune system's functionality, the core purpose of