Abbreviation: NK cell.
A large granular lymphocyte, a defensive cell of innate immunity, that bonds to cells and lyses them by releasing cytotoxins. Unlike other lymphocytes, these cells do not have B cell or T cell surface markers, and they can be activated without previous antigen exposure. NK cells destroy cells infected with viruses and some types of tumor cells in cultures. They also secrete gamma interferon (INFγ), tumor necrosis factor alpha (TNFα), and granulocyte-macrophage colony-stimulating factor (GMCSF), enhancing the effect of T lymphocytes.

Main entry:
cell