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

The team says that future work should focus on improving the technique and potentially extending it beyond CAR T cell therapy. —Michael Irving, New Atlas, 9 Dec. 2024

The company is considering whether T cells can be collected via a standard blood donation, rather than the current multihour blood filtration process. —Byjennifer Couzin-Frankel, science.org, 14 Nov. 2024

Both the Moderna and Pfizer-BioNTech Covid vaccines produce long-lasting T cells in addition to antibodies. —Emily Mullin, WIRED, 12 Sep. 2023

But what if the CAR T cells could be altered to withstand the ovarian tumor environment? —William A. Haseltine, Forbes, 31 Oct. 2024

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