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

One study suggested that sleep helps the body's infection-fighting T cells work more efficiently. —Karen Pallarito, Health, 27 Sep. 2023

Experts believe T cells may be recognizing the virus’ nucleocapsid protein, which forms the core structure of the virus, and which remains relatively similar among the various variants that have appeared so far. —Alice Park, Time, 26 Sep. 2023

Unlike antibodies, which neutralize a pathogen by preventing it from infecting cells, T cells work by eliminating the cells that have already been invaded and boosting creation of more antibodies. —Emily Mullin, WIRED, 12 Sep. 2023

Immune cells known as T cells persist and continue to protect against severe disease, however. —Tanya Lewis, Scientific American, 1 Sep. 2023

The procedure, regulated as a drug, involves taking T cells from a patient’s blood, adding chimeric antigen receptors (CAR) to the T cells that kill cancer, and injecting the CAR-T treatment back into the patient. —John Wilkerson, STAT, 20 July 2023

To make this determination, the study’s authors took samples of T cells — an important part of the body’s immune system — that had been collected years before the pandemic began and introduced them to pieces of SARS-CoV-2 in a laboratory setting. —Rong-Gong Lin Ii, Los Angeles Times, 19 July 2023

Once trained, T cells can travel anywhere in the body to hunt down danger. —Carla K. Johnson, Chicago Tribune, 26 June 2023

Then, the T cells multiply and target the tumor cells that have neoantigens on them, attacking and potentially destroying them. —Alyssa Hui, Verywell Health, 16 May 2023

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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