A type of lymphocyte normally present in the body. Their responsibility is to kill cells that are infected with viruses. Rarely, these cells can transform to a form of leukemia or lymphoma.

Cells which engulf an infected cell.

immune cells with "clean up" functions; removal of damaged tissue or abnormal cells

Cells capable of mediating cytotoxic reaction without prior sensitization against the target. NK cells are small lymphocytes. Their cytotoxic activity is not antibody-dependent. NK cells can lyse a wide variety of tumor cells and other cell types.

Cells in the immune system which attack and destroy infected cells or tumour cells.

white blood cells that can destroy a range of antigens on contact.

A type of lymphocyte that attacks and kills tumor cells and protects against a wide variety of infectious microbes. They do not need additional stimulation to attack. Persons with HIV have a decrease in these cells.

A type of lymphocyte that is capable of attacking any foreign invader in the body with lethal chemicals.

A subset of bone marrow-derived lymphocytes, distinct from B or T cells, that function in innate immune responses to kill microbe infected cells by direct lytic mechanisms and by secreting INF-?. NK cells do not express clonally distributed antigen receptors like Ig receptors or TCRs, and their activation is coordinated by a combination of cell surface stimulatory and inhibitory receptors, the later recognizing self MHC molecules.

Immune system cells that destroy foreign bodies or abnormal cells that are marked with antibodies.

A highly specialized group of immune cells that are acutely attracted to certain unwanted cells in the body.

Natural killer (NK) cells guard the blood and lymphatic system. They are a unique group of defensive cells that can disintegrate and kill cancer cells and virus-infected body cells.

a lymphocyte (white blood cell) that attacks and destroys infected or cancer-causing cells without antigen stimulation.

A type of lymphocyte. Like cytotoxic T cells, NK cells attack and kill tumor cells and protect against a wide variety of infectious microbes. They are "natural" killers because they do not need additional stimulation or need to recognize a specific antigen in order to attack and kill. Persons with immunodeficiencies such as those caused by HIV infection have a decrease in "natural" killer cell activity. See Antigen; B Lymphocytes; T Cells; Null Cell.

A group of lymphocytes made in the bone marrow. As their name implies, they destroy other cells, which have been identified as faulty. They are part of the body's immune defence system.

Specialized lymphocytes that are important in detecting and eliminating tumor cells and virus-infected cells.

NK cells. A type of white blood cell that contains granules with enzymes that can kill tumor cells or microbial cells. Also called large granular lymphocytes (LGL).

Large granule-filled lymphocytes that take on tumor cells and infected body cells. They are known as "natural" killers because they attack without first having to recognize specific antigens.

NK cells are a type of lymphocyte. Like cytotoxic T-cells, NK cells attack and kill tumor cells and protect against a wide variety of infectious microbes. They are "natural" killers because they do not need additional stimulation or need to recognize a specific antigen in order to attack and kill harmful cells. Dendritic cells can activate NK cells.

Cells of the innate immune system involved in attacking tumor cells without recognizing specific antigen

Related Topic"An important first line of defense against newly arising malignant cells and cells infected with viruses, bacteria, and protozoa..."

Related Topic"...Natural Killer Cells constitute 5 to 16% of the total lymphocyte population..."