NK cell

NK cell

NK cells, or natural killer cells, are a type of lymphocyte (a white blood cell) and a component of innate immune system. NK cells play a major role in the host-rejection of both tumors and virally infected cells.

Function

NK cells are unique as they have the ability to recognize stressed cells in the absence of antibodies and MHC, allowing for a much faster immune reaction. They were named "natural killers" because of the initial notion that they do not require activation to kill cells that are missing "self" markers of MHC class I.

Development

NK cells are derived from hematopoietic stem cells (HSCs) in the bone marrow. They then travel to the thymus, where they undergo a process of maturation and differentiation.

Clinical significance

NK cells are of interest in clinical medicine for their potential in cancer immunotherapy. Their ability to rapidly respond to virus-infected cells and tumor formation is important for controlling these diseases before they can establish. Furthermore, NK cells also contribute to immunoregulation by secreting high amounts of cytokines.

See also

• Adaptive immune system
• Innate immune system
• Lymphocyte
• Cytokine
• Immunotherapy