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

Retinoic acid then triggers the development of regulatory T cells (T-regs), immune cells that suppress the body’s allergic response. —New Atlas, 21 Dec. 2024

Before and after periods of play, the children’s skin and gut microbiota were measured using genetic sequencing of bacteria taken from skin swabs and stool samples, along with changes to T cells and cytokines in their blood. —Kathy Willis, WIRED, 21 Dec. 2024

Earlier this year, researchers at Stanford demonstrated that infusions of CAR T cells into the brains of pediatric patients with brain cancer could offer new hope. —Juergen Eckhardt, Forbes, 19 Dec. 2024

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

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