Description: The GB11 antibody reacts with human Granzyme B (GrB). GrB is one of the family of serine proteases, known as granzymes, that is located in the granules of cytotoxic T cells and NK cells. Granzyme B has been described also as CGL1 (cathepsin G-like-1), a serine protease expressed only in cytotoxic T-lymphocytes after cell activation. GrB has been called CTLA-1 (cytotoxic T lymphocyte-associated serine esterase 1) based on identification of mRNA in various cytotoxic T cells, but not observed in non-cytotoxic lymphoid cells. GrB is crucial for the rapid induction of target cell death by apoptosis, induced by interaction with cytotoxic T cells. The receptor involved has been identified as mannose 6-phosphate receptor. This receptor functions as a death receptor for granzyme B during cytotoxic T cell-induced apoptosis.