T Cells:Regulation and Cellular Immunity
T lymphocytes mature in the thymus. T cells regulate the development, proliferation and activity of B cells, T cells, and other cells participating in immune responses; they are also effectors of antigen-specific cell-mediated immunity (CMI). CMI is important in the elimination of cells infected with pathogens which replicate intracellularly (e.g., viruses, rickettsia, and some bacteria) and cells exhibiting aberrant cytodifferentiation (neoplastic cells). CMI also destroys allogeneic cells (graft rejection).