NCIt definition : A humanized bivalent antibody directed against both cytotoxic effector cells expressing
Fc gamma receptor type I (Fc gammaRI, or CD64) and HER2/neu-overexpressing tumor cells
with potential antineoplastic activity. Bispecific antibody MDX-H210 was constructed
by chemically linking Fab' fragments of the anti-HER2/neu-specific monoclonal antibody
520C9 and the Fab' fragments of the anti-Fc gammaRI-specific monoclonal antibody H22.
This agent selectively binds to both HER2/neu-expressing tumor cells and Fc gammaRI-expressing
cytotoxic effector cells, which may trigger antibody-dependent cell-mediated cytotoxicity
(ADCC) and cell lysis of HER2/neu-expressing tumor cells. While HER2/neu is overexpressed
in a variety of epithelial malignancies, expression of Fc gammaRI is primarily found
in cytotoxic immune cells, including monocytes, macrophages, and cytokine-activated
polymorphonuclear (PMN) cells.;