Hepatocyte growth factor receptor
Passive immunotherapy
#### Passive immunotherapy

Administering [monoclonal antibodies](/wiki/Monoclonal_antibodies "Monoclonal antibodies") (mAbs) is a form of passive immunotherapy. MAbs facilitate destruction of tumor cells by [complement\-dependent cytotoxicity](/wiki/Complement-dependent_cytotoxicity "Complement-dependent cytotoxicity") (CDC) and cell\-mediated cytotoxicity ([ADCC](/wiki/Antibody-dependent_cell-mediated_cytotoxicity "Antibody-dependent cell-mediated cytotoxicity")). In CDC, mAbs bind to specific [antigen](/wiki/Antigen "Antigen"), leading to activation of the [complement cascade](/wiki/Complement_cascade "Complement cascade"), which in turn leads to formation of pores in tumor cells. In ADCC, the Fab domain of a mAb binds to a [tumor antigen](/wiki/Tumor_antigen "Tumor antigen"), and Fc domain binds to Fc receptors present on effector cells ([phagocytes](/wiki/Phagocytes "Phagocytes") and [NK cells](/wiki/NK_cells "NK cells")), thus forming a bridge between an effector and a target cells. This induces the effector cell activation, leading to [phagocytosis](/wiki/Phagocytosis "Phagocytosis") of the tumor cell by [neutrophils](/wiki/Neutrophils "Neutrophils") and [macrophages](/wiki/Macrophages "Macrophages"). Furthermore, [NK cells](/wiki/NK_cells "NK cells") release [cytotoxic](/wiki/Cytotoxic "Cytotoxic") molecules, which lyse tumor cells.

* DN30 is monoclonal anti\-MET antibody that recognizes the extracellular portion of MET. DN30 induces both [shedding](/wiki/Proteases_in_angiogenesis%23Ectodomain_shedding "Proteases in angiogenesis#Ectodomain shedding") of the MET [ectodomain](/wiki/Ectodomain "Ectodomain") as well as cleavage of the intracellular domain, which is successively degraded by [proteasome](/wiki/Proteasome "Proteasome") machinery. As a consequence, on one side MET is inactivated, and on the other side the shed portion of extracellular MET hampers activation of other MET receptors, acting as a decoy. DN30 inhibits tumour growth and prevents [metastasis](/wiki/Metastasis "Metastasis") in animal models.
* OA\-5D5 is one\-armed monoclonal anti\-MET antibody that was demonstrated to inhibit orthotopic pancreatic and [glioblastoma](/wiki/Glioblastoma "Glioblastoma") tumor growth and to improve survival in [tumor xenograft models](/wiki/Tumor_xenograft_model "Tumor xenograft model"). OA\-5D5 is produced as a [recombinant protein](/wiki/Recombinant_protein "Recombinant protein") in *[Escherichia coli](/wiki/Escherichia_coli "Escherichia coli")*. It is composed of murine [variable domains](/wiki/Variable_domain "Variable domain") for the [heavy](/wiki/Immunoglobulin_heavy_chain "Immunoglobulin heavy chain") and [light chains](/wiki/Immunoglobulin_light_chain "Immunoglobulin light chain") with human IgG1 constant domains. The antibody blocks HGF binding to MET in a competitive fashion.

What is complement-dependent cytotoxicity (CDC)?