The MaxDiscovery™ Mouse Granzyme B ELISA Test Kit is designed for quantitative determination of the concentration of mouse granzyme B in serum, plasma, and cell culture supernatant. Mouse granzyme B is a ~25 kDa protein of 227 amino acids (aa) after cleavage of a 20 aa signal peptide. It is a member of the Granzyme family of exogenous serine proteases and is one of the eleven Granzymes (A,B,C,D,E,F,G,K,M,N,O) found in the mouse genome. Granzymes are released by cytoplasmic granules within cytotoxic T lymphocytes (CTL) and natural killer (NK) cells. Their purpose is to induce apoptosis within virus-infected tumorigenic cells, thus destroying them. Granzyme B works in conjunction with the protein perforin to induce apoptosis in target cells by forming transmembrane pores and through cleavage of effector caspases such as caspase-3. A caspase-independent mechanism of granzyme B-mediated apoptosis has also been suggested. Granzyme B may have roles in rheumatoid arthritis and in bacterial and viral infections. Measuring granzyme B release in response to the appropriate target is useful for evaluating cell-mediated cytotoxicity.