A<unk>  is a large granular lymphocyte that develops inside the bone marrow.<unk> s lack the common characteristic surface markers that can be found in mature B-cells and T-cells. They are rapidly stimulated in the presence of pathogens like viruses and attack viral-infected or tumor cells in a non MHC-restricted manner.<unk> s make up a small proportion of the lymphocytes that can be found in an organism. The term<unk>  is no longer commonly used; they are normally referred to as natural killer (NK) cells or killer cells. In subpopulations of mononuclear cells in aging human, the number of<unk> s has been shown to increase over time. Recently, using developed monoclonal antibodies against natural killer cells combined with T-Cell markers in two wavelength immunofluorescence 13 subpopulations of mononuclear cells were defined and compared in two groupings of individuals. What was found was that in the elderly (75-84) age group was an increase in the<unk>  population because of an increase in natural killer cells. More specifically, the CD16+ and Leu7+ subset of natural killer cells. Additionally, CD8+ suppressor and cytotoxic cells were found to be decreased. Changes are believed to be due to defects involved with an aging immune system and can be used as a representation of a healthy immune system in the healthy aged group and can be linked to survival. The values that were uncovered can be implemented in monitoring efforts to rebuild defective immune systems due to aging.<unk> s have also been found in some cancers. In the pituitary gland,<unk>  adenomas have been found.<unk> s have also been identified in nontumorous adeno-hypophysis. This suggests that<unk>  adenomas are derived from preexisting non-neoplastic<unk> s.
Null cell
Hürthle cell
Aschoff cell
Clue cell
Navicular cell
Buttock cell
Signet ring cell
Granule cell