Natural killer (NK) cells

Definition

Natural killer (NK) cells are a type of lymphocyte (a white blood cell) that play a critical role in the innate immune response by targeting and destroying virally infected cells and tumor cells. NK cells recognize stressed cells in the absence of antibodies and MHC, allowing for a rapid immune response.

Related terms

Lymphocytes:

White blood cells that are part of the immune system, including B cells, T cells, and natural killer cells.

Innate Immune System: The first line of defense in the immune system that includes barriers, cellular defenses, and soluble proteins to protect against pathogens.

Major Histocompatibility Complex (MHC):

Molecules found on the surfaces of all body cells that help the immune system recognize foreign substances