Natural cytotoxicity receptors include now three molecules specific for unknown host ligands: NKp46, NKp30, and NKp44 (8, 9), which mediate cell lysis of many cancer cells. Additional surface molecules have been implicated in NK cell activation and tumor cell lysis; these include 2B4, NTB-A, NKp80 coreceptors, CD18/CD11 (ß2 integrins), CD2 adhesion molecules, and TLR (8, 9, 12, 16, 17). In particular, viral and bacterial products can trigger NK cell responses directly binding to surface TLR3 and TLR9 (16, 17). More in general, NK cells can be activated by various stimuli such as contact with dendritic cells (DC), MHC-I-negative cells, binding of IgG immunocomplexes, direct engagement of NKR by stress-induced tumor-associated molecules or pathogen-derived products, and several cytokines such as IL-1, IL-2, IL-12, IL-15, IL-18, IL-21, and type I IFNs (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25). Upon cytokine stimulation, NK cells become lymphokine-activated killer (LAK) cells.
NK cells can be identified by the presence of CD56 and CD16 and a lack of CD3 cell surface markers. NK cells are capable of killing virus-infected and malignant target cells but they are relatively inefficient in doing so. However, upon exposure to IL-2 and IFN-gamma, NK cells become lymphokine-activated killer (LAK) cells, which are capable of killing malignant cells. Continued exposure to IL-2 and IFN-gamma enables the LAK cells to kill transformed as well as malignant cells.
In cell biology, a lymphokine-activated killer cell (also known as a LAK cell) is a white blood cell that has been stimulated to kill tumor cells.  If lymphocytes are cultured in the presence of Interleukin 2, it results in the development of effector cells which are cytotoxic to tumor cells.
Abbreviation for lymphokine-activated killer cell. These natural killer cells, obtained from the patient's blood, have been activated in culture with interleukin-2. LAK cells; the cells can then be used to treat patients with solid malignant tumors.
Read about the Issels cancer treatment protocols using Cytokines, Natural Killer cells or NK cells, Lymphokine-Activated Killer cells or LAK cells, and stem
Natural killer cells are usually null cells with surface marker CD 16 which bind to the Fc portion of the IgG, and thereby destroy it. NK-cells do immune surveillance, attack pathogens and abnormal cells. Members of null cells are NK cells, antigen dependent cytotoxic cells(ADCC), and the lymphokine activated killer(LAK)cells. In 75% of the cases of ALL, the lymphocytes are neither B nor T-cells and are called Null cells.