T cell

T cell A type of white blood cell that is made in the bone marrow and migrates to the thymus gland, where it matures, differentiates into various types of T cells, and becomes active in the immune system. There are several types of mature T cells. Most of the T cells in the body belong to one of two subsets known as T-4 cells and T-8 cells. T-8 cells are cytotoxic T lymphocytes that can produce cytokines, such as the interleukins, which in turn further stimulate the immune response. T-cell activation is measured to assess the health of patients with HIV. Also known as T lymphocyte. See also natural killer cell; T-4 cell; T lymphocyte, cytotoxic; T-suppressor cell.