Cytotoxic T cells, also known as CD8+ T cells, are a type of white blood cell that play a crucial role in the immune system. They are responsible for identifying and destroying infected or cancerous cells in the body. These cells recognize specific antigens presented on the surface of infected cells, allowing them to target and eliminate threats effectively. Once activated, cytotoxic T cells release proteins that induce apoptosis, or programmed cell death, in the infected cells. This process helps to prevent the spread of infection and maintain the overall health of the organism. Their activity is essential for controlling viral infections and tumor growth.