Cytotoxic T cells, also known as CD8+ T cells, are a type of T lymphocyte that play a critical role in the immune system’s defense against viral infections and cancer. They are called “cytotoxic” because they are capable of directly killing infected or abnormal cells in the body.
Cytotoxic T cells recognize and bind to antigens presented on the surface of infected or abnormal cells by MHC class I molecules. This interaction triggers the activation and proliferation of the cytotoxic T cells, which then differentiate into effector cells that can directly kill the target cells.
The effector cytotoxic T cells release perforin and granzymes, which can induce apoptosis (programmed cell death) in the target cell. They also release cytokines such as interferon-gamma, which can further enhance the immune response by activating other immune cells.
In addition to their role in fighting infections and cancer, cytotoxic T cells are also important in transplant medicine. They can recognize and attack foreign tissues that are not matched to the recipient’s own tissue type, which can cause transplant rejection. Therefore, immunosuppressive drugs are often used to prevent cytotoxic T cell-mediated rejection in transplant recipients.
