Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
T cells are a type of lymphocyte (white blood cell) that play a central role in cell-mediated immunity, originating from bone marrow and maturing in the thymus. They can directly attack virus-infected cells, cancer cells, and transplanted cells.
Related terms
Immune response: The body's defensive reaction to foreign substances or pathogens involving recognition, mobilization, attack, and homeostasis restoration.
Antigen: Any substance that triggers an immune response by being recognized as foreign by the immune system, often leading to antibody production.
A primary lymphoid organ located in the upper chest where T cells mature before they are released into the bloodstream to perform their immune functions