What is the role of cytotoxic T cells in the immune response?

Cytotoxic T cells, also known as CD8+ T cells, play a crucial role in the immune response by directly destroying infected or abnormal cells. This function is vital for controlling infections, especially those caused by intracellular pathogens such as viruses. When a cell becomes infected, it presents foreign antigens on its surface. Cytotoxic T cells recognize these antigens through their T cell receptors, leading to their activation. Once activated, they can induce apoptosis, or programmed cell death, in the infected cells, thereby eliminating the source of the infection.

This destruction is particularly important because it helps to prevent the replication and spread of pathogens within the body. In addition to their role in killing infected cells, cytotoxic T cells also produce cytokines, which can further influence the immune response, but their primary and defining function is the direct cytotoxic activity against infected or cancerous cells.