Natural Killer Cells are a Form of Granular Lymphocytes of Varying Sizes that Play an Important Role in Innate Immunity in the Human Body

 

Natural Killer Cells

Natural Killer (NK) Cells are lymphocytes that share a common progenitor with T and B cells and belong to the same family. However, NK cells are categorised as group I Innate Lymphocytes (ILCs), which are cells of the innate immune system, and they react fast to a wide range of pathogenic stimuli. NK cells are well recognised for destroying virally contaminated cells as well as for spotting and managing early cancer indications. Specialized NK cells are present in the placenta and may be crucial throughout pregnancy in addition to defending against illness.

Natural killer cells, also referred to as NK cells or large granular lymphocytes (LGL), are a subset of cytotoxic lymphocytes important for the innate immune system that make up between 5-20% of all circulating lymphocytes in humans. They are members of the rapidly growing family of known innate lymphoid cells (ILC). In the vertebrate adaptive immune response, the function of NK cells is comparable to that of cytotoxic T cells. NK cells respond quickly to the development of tumours as well as intracellular pathogens working three days after infection and on virus-infected cells.

Immune cells often recognise the MHC molecules on the surfaces of infected cells, which leads to the production of cytokines and the death of the infected cell through lysis or apoptosis. However, NK cells are special because they can identify stressed cells and kill them even in the absence of antibodies and MHC, triggering an immune response much more quickly. Because they kill cells that lack MHC class 1 "self" signals without activation, they were given the term "natural killers." This function is particularly crucial because other immune cells, such as T lymphocyte cells, cannot identify and eliminate dangerous cells lacking MHC I markers.