T cell

noun

: any of several lymphocytes (such 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 of cell-mediated and humoral immunity (as by the regulation of T and B cell maturation and proliferation) and others that lyse antigen-bearing cells : t lymphocyte

The immature lymphoid cell, in turn, can be processed into a B cell, which makes infection-fighting antibodies, or a T cell, which recognizes foreign tissue and virally infected cells and directs the activities of the rest of the immune system.

—Gina Kolata

T cells recognize antigen only in association with cell surface molecules encoded by the major histocompatibility complex …

—Miranda Robertson

see helper t cell, killer t cell compare b cell

Examples of T cell in a Sentence

Recent Examples on the Web

That’s because the damage helps to lure in tumor-fighting T cells. —Elie Dolgin, Ars Technica, 21 June 2024

The apotheosis of such work may be the development of chimeric antigen receptor T cell, or CAR-T, therapies, which debuted in 2017 and reengineer the body's own specialized immune system cells to combat cancers. —Maryn McKenna, Scientific American, 1 Sep. 2020

The autoimmune shift is supported by data presented last December by a group of German scientists who used personalized T cells — CAR-T therapy — to induce complete remissions in 14 patients with severe autoimmune disease, including eight patients with lupus. —Meghana Keshavan, STAT, 5 Apr. 2024

But over the last few years, researchers in Germany have begun testing the potential of CAR-T therapy — a cutting-edge cancer treatment in which a patient’s immune T cells are genetically modified in a lab to better attack disease targets — to help those with autoimmune disorders. —Theresa Gaffney, STAT, 21 Feb. 2024

Evidence of Gene-Editing The lentiviral and enveloped delivery vectors successfully transformed a percentage of T cells into CAR-bearing T cells. —William A. Haseltine, Forbes, 14 Feb. 2024

If these are from an invader, such as a virus, or show the cell is otherwise malfunctioning, this signals the immune system T cells to respond.2 The Role of Antigens Antigens are immune response initiators. —Angelica Bottaro, Verywell Health, 16 Jan. 2024

The acids, in turn, weakened the animals’ T cells — immune-system warriors that go rogue in autoimmune disorders. —Kenneth Miller, Discover Magazine, 11 Dec. 2023

The treatment involves intravenous drips of the patient’s own T cells, reëngineered in a laboratory to bind with specific antigens on the surface of the patient’s cancer cells. —Casey Cep, The New Yorker, 4 Dec. 2023

Word History

Etymology

thymus-derived cell

First Known Use

1970, in the meaning defined above

Kids Definition

T cell

noun

: any of the lymphocytes (as a helper T cell) that usually mature in the thymus and take an active part in immune responses compare b cell

Medical Definition

T cell

noun

: 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 of cell-mediated and humoral immunity (as by the regulation of T and B cell maturation and proliferation) and others that lyse antigen-bearing cells

called also T lymphocyte

see cytotoxic t cell, helper t cell, suppressor t cell, t4 cell