Coloured transmission electron micrograph (TEM) of a lymphocyte (blue) passing through the endothelium of a capillary. A lymphocyte is one of the subtypes of a white blood cell in a vertebrate's immune system. Lymphocytes include natural killer cells (NK cells), which function in cell-mediated, cytotoxic innate immunity, T cells, for cell-mediated, cytotoxic adaptive immunity, and B cells, for humoral, antibody-driven adaptive immunity. They are the main type of cell found in lymph, which prompted the name lymphocyte. Magnification: x5, 100 at 10 centimetres tall. |