T cell
Học thuậtThân thiện
Definition
Noun A type of lymphocyte (white blood cell) that matures in the thymus gland. T cells are central to the adaptive immune system, responsible for identifying and coordinating the destruction of cells that are infected by pathogens or have become cancerous.
Usage
The term "T cell" is used in medical, biological, and immunological contexts to describe a key component of the body's immune defense. It is often discussed in relation to specific types of immune responses, diseases, and therapies. * The body produces millions of T cells to fight the infection. * Research focuses on how T cells recognize foreign antigens. * A low T cell count can indicate a compromised immune system.
Advanced Usage
- Cytotoxic T cell (CD8+): A T cell that directly kills infected or cancerous cells.
- Cytotoxic T cells are essential for eliminating virus-infected cells.
- Helper T cell (CD4+): A T cell that activates and directs other immune cells by releasing signaling molecules called cytokines.
- Helper T cells are the primary target of HIV.
- Regulatory T cell (Treg): A T cell that suppresses the immune response to prevent excessive reaction and autoimmunity.
- Regulatory T cells help maintain immune tolerance.
- Memory T cell: A long-lived T cell that "remembers" a specific pathogen for a faster response upon future exposure.
- Vaccines work by generating memory T cells and B cells.
Variants and Related Words
- T lymphocyte: A formal, synonymous term for T cell.
- Thymocyte: An immature T cell that is developing in the thymus.
- B cell: Another major type of lymphocyte, which matures in the bone marrow and produces antibodies.
Synonyms
- T lymphocyte
Related Phrases and Concepts
- T cell receptor (TCR): The molecule on the surface of a T cell that recognizes fragments of antigens.
- T cell activation: The process by which a T cell is stimulated to proliferate and perform its immune functions.
- T cell-mediated immunity: The immune response carried out primarily by T cells, as opposed to antibody-driven (humoral) immunity.
- Adoptive T cell therapy: A treatment where a patient's own T cells are collected, modified, and reinfused to attack cancer cells.
Noun
- a small lymphocyte developed in the thymus; it orchestrates the immune system's response to infected or malignant cells