Granzymes are serine proteases that are released by cytoplasmic granules within cytotoxic T cells and natural killer cells. Human Granzyme B is one of the five members of the human granzyme family which includes Granzymes A, B, G, H, and K. Granzyme B is also known as Granzyme 2, serine protease B (CSP-B for cytotoxic serine protease B), and CCP1 (cytotoxic cell protease-1). It is expressed as a 32 kD protein encoded by the GZMB gene. While Granzyme B is mostly expressed by CTL (Cytotoxic T Lymphocyte) and NK cells, it is also expressed in resting and activated plasmacytoid dendritic cells. Much lower levels are found in monocytes, resting T-cells, B-cells, activated granulocytes, and activated monocyte-derived dendritic cells. Granzyme B is crucial for the rapid induction of target cell apoptosis by CTL in the cell-mediated immune response. Granzyme B and perforin have been shown to induce CTL-mediated target cell DNA fragmentation and apoptosis. Once released from the CTL, Granzyme B binds its receptor, the mannose-6-phosphate/ insulin-like growth factor II receptor, and is endocytosed but remains arrested in endeocytic vesicles until released by perforin. Once in the cytosol, Granzyme B targets caspase-3 and other caspases directly or indirectly through the mitochondria, initiating the caspase cascade which leads to DNA fragmentation and apoptosis. Elevated Granzyme B levels have been linked with various disease processes. For example, increased levels of soluble granzymes have been found in patients with systemic viral infections. It has also been shown that the presence of a high percentage of Granzyme B positive CTLs in the glands of patients suffering from Hodgkin's disease correlates with a severe prognosis. Synovial fluid from rheumatoid arthritis patients has elevated soluble Granzyme A and B levels compared with healthy donors and patients with osteoarthrosis. BioLegend's LEGEND MAX(TM) Human Granzyme B ELISA Kit is a sandwich Enzyme-Linked Immunosorbent Assay (ELISA), in which, a human Granzyme B -specific monoclonal antibody is pre-coated on a 96-well strip-well plate. BioLegend's LEGEND MAX(TM) Human Granzyme B ELISA Kit is specifically designed for the accurate quantitation of Human Granzyme B from cell culture supernatant, serum, plasma, or other bodily fluids. It is ready-to-use, accurate, and sensitive.