A variety of white blood cell produced in the LYMPHOID TISSUE and lymphatic glands (see LYMPHATICS; GLAND) of the body. It contains a simple, rounded nucleus surrounded by protoplasm generally described as non-granular. Two varieties of lymphocyte are described, small and large, and together they form over 20 per cent of the white cells of the blood. They play an important part in the production of ANTIBODIES, and in the rejection of transplanted organs such as the heart (see TRANSPLANTATION). This they do in two di?erent ways: what are known as B-lymphocytes produce antibodies, while T-lymphocytes attack and destroy antigens (see ANTIGEN) directly. The latter are known as T-lymphocytes because they are produced by the THYMUS GLAND. Their numbers are increased in TUBERCULOSIS and certain other diseases. Such an increase is known as LYMPHOCYTOSIS.... lymphocyte
A type of white blood cell that circulates through the body and is able to detect the presence of the foreign agents. Once exposed to an antigen on the agent, these cells differentiate into plasma cells to produce antibody.... b-lymphocyte (or b-cell)
White blood cells that have matured in the thymus gland. There are at least two kinds of T-lymphocytes - helpers and suppressors. In AIDS, the number of helper cells is decreased.... t-lymphocytes (or t-cells)
(TIL) a lymphoid cell that can infiltrate solid tumours. Such cells can be cultured in vitro, in the presence of *interleukin 2, and have been used as vehicles for *tumour necrosis factor in gene therapy trials for cancer.... tumour-infiltrating lymphocyte
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