- Proteins on the surface of cells that are capable of detection by antibodies or other means. These may stimulate an immune response.
- A type of white blood cell that is of crucial importance to the immune system. Immature T cells (termed T-stem cells) migrate to the thymus gland in the neck, where they differentiate into various types of mature T cells and become active in the immune system. T cells that are potentially activated against the body’s own tissues are normally killed or changed (“down-regulated”) during this maturation process.
- Growth of tissue in vitro on an artificial media for experimental research.
- Not having changed to become a specialized cell type.
White blood cell
- Also known as a leukocyte. These cells normally protect against infection by, for example, ingesting bacteria or secreting antibodies. White blood cells are formed from the undifferentiated stem cell that can give rise to all blood cells. Those in the bone marrow may become any of the five types of white blood cells. Those in the spleen and lymph nodes may become lymphocytes, or monocytes, and those in the thymus can become lymphocytes (T-lymphocytes).
- The cell formed by the union of male and female germ cells (sperm and egg, respectively).