A Level Biology Practice Exam

Which T lymphocytes are responsible for destroying pathogens with a specific antigen?

1. T helper cells

2. T killer cells

3. T memory cells

4. T regulator cells

The correct answer is: T killer cells

T killer cells, also known as cytotoxic T lymphocytes, play a crucial role in the immune response by directly attacking and destroying cells that display specific antigens associated with pathogens, such as viruses or cancer cells. When a T killer cell recognizes an antigen presented by an infected or abnormal cell, it can initiate cell death through various mechanisms, such as the release of perforins, which create pores in the target cell's membrane, and granzymes that induce apoptosis. This targeted approach allows the immune system to eliminate specific threats effectively while preserving healthy cells, which is essential for maintaining overall health and combating infections. The specificity of T killer cells is a key aspect of adaptive immunity, allowing for a finely tuned immune response that is not only rapid but also capable of remembering past infections, enhancing the efficiency of future responses to the same pathogens. T helper cells assist other cells of the immune system, T memory cells serve to remember past pathogens for a quicker response upon re-exposure, and T regulator cells help to maintain immune homeostasis and prevent autoimmune responses, but it is the T killer cells that are specifically tasked with seeking out and destroying infected or cancerous cells based on their unique antigen profiles.