T cell
T cell T" cell` (t[=e]"s[e^]l`) [From Thymus, the site of maturation of T-cells.] A type of white blood cell that circulates in the blood and lymph, and provides cell-mediated immunity for the organism, protecting against infecting cells or the body's own malignant cells; also called {T lymphocyte}. There are several types of T cells. They develop, as do B cells, from progenitor cells in the bone marrow, but are distinguished from B-cells (B-lymphocytes) by their site of differentiation; T-cells mature in the thymus and B-cells in the bone marrow (in birds in the Bursa of Fabricius). They also have different antigen receptors from those of B-cells. T-cells differentiate into cells that can directly kill infecting cells (cell-mediated immunity, cytotoxity) or activate other cells of the immune system (helper T cells), whereas B-cells differentiate on activation into antibody-secreting plasma cells. Helper T cells interact with B-cells by secreting lymphokines that stimulate the B cell which have detected a foreign antigen to enter the cell cycle and develop, by repeated mitosis, into a clone of cells with identical receptors, and then to secrete antibodies to that specific antigen. [PJC]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • T cell — T cells belong to a group of white blood cells known as lymphocytes, and play a central role in cell mediated immunity. They can be distinguished from other lymphocyte types, such as B cells and natural killer cells by the presence of a special… …   Wikipedia

  • T-cell — Tˈ cell noun A type of lymphocyte involved in cellular immunity that matures (in mammals) in the thymus gland, eg a cytotoxic T cell able to kill virus infected cells • • • Main Entry: ↑T * * * T cell, or T cell «TEE SEHL», noun. a type of… …   Useful english dictionary

  • T cell — [ˈti: sel] n British English medical [Date: 1900 2000; Origin: T from thymus derived] a type of ↑white blood cell that helps the body fight disease …   Dictionary of contemporary English

  • T-cell — T cells N COUNT A T cell is a type of white blood cell …   English dictionary

  • T cell — n. [< t(hymus)] any of the lymphocytes that are affected by the thymus and are involved in rejecting foreign tissue, regulating cellular immunity, and controlling the production of antibodies in the presence of an antigen: cf. B CELL …   English World dictionary

  • T cell — [ ti sel ] noun count a type of white blood cell that helps the body fight disease …   Usage of the words and phrases in modern English

  • t cell — 1970; so called because they are derived from the THYMUS (Cf. thymus) …   Etymology dictionary

  • T cell — noun a small lymphocyte developed in the thymus; it orchestrates the immune system s response to infected or malignant cells • Syn: ↑T lymphocyte • Hypernyms: ↑lymphocyte, ↑lymph cell • Hyponyms: ↑helper T cell, ↑ …   Useful english dictionary

  • T cell — A type of white blood cell that is of crucial importance to the immune system. Immature T cells (termed T stem cells) migrate to the thymus gland in the neck, where they mature and differentiate into various types of mature T cells and become… …   Medical dictionary

  • T cell — noun Etymology: thymus derived cell Date: 1970 any of several lymphocytes (as a helper T cell) that differentiate in the thymus, possess highly specific cell surface antigen receptors, and include some that control the initiation or suppression… …   New Collegiate Dictionary

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