7-AAD/CFSE Cell-Mediated Cytotoxicity Assay Kit

Catalog Number

600120

P Type

Assay Kits

Storage Temp

-20

Additional Info

Cell-mediated cytotoxicity is characterized by cytolysis of a target cell by effector cells such as cytotoxic T lymphocytes or natural killer cells. It is a major part of the immune system in which the body protects itself from attack by invading pathogens and is fundamental in maintaining homeostasis of the immune system. Dysfunction of cytotoxic T lymphocytes or natural killer cells results in pathological conditions such as multiple sclerosis and cancer. Cell-mediated cytotoxicity is a complex, multistep process which is mediated by several different pathways, including the granule exocytosis pathway and the Fas pathway. The interplay between these pathways provides opportunities for therapeutic interventions to control autoimmune diseases and graft versus host disease. Cell-mediated cytotoxicity has typically been assessed using the 51chromium (51Cr) release assay, in which the target cells are labeled with 51Cr. This method has disadvantages including the use of radioisotopes and low sensitivity. More sensitive and convenient methods have been developed using green fluorescent probes such as 5-(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) to label target cells, in combination with red fluorescent probes such as 7-AAD or propidium iodide to label dead effector and dead target cells. CFSE passively diffuses into cells and its acetate groups are cleaved by intracellular esterases to yield higly fluorescent carboxyfluorescein succinimidyl ester. 7-AAD and propidium iodide are fluorescent dyes which are excluded from live cells but penetrate dead or damaged cells to label DNA. The labeling distinguishes four populations of cells: 1) living target cells in green, 2) dead target cells in green and red, 3) dead effector cells in red, and 4) live effector cells, which remain unstained. Thus, the cytotoxicity of the effector cells can be evaluated quantitatively. Cayman