Definition

A radioimmunoconjugate consisting of the iodine I 124-radiolabeled murine IgG1 monoclonal antibody omburtamab directed against the cell surface glycoprotein CD276 (4Ig-B7-H3) with potential for radioimaging using positron emission tomography (PET). Through convection enhanced delivery of iodine I 124 omburtamab, the antibody moiety binds to the 4Ig domain of CD276, and in turn CD276-expressing tumor cells may be visualized upon PET imaging of the iodine I 124 moiety. CD276, a tumor-associated antigen (TAA) and member of the B7 family of co-stimulatory proteins, suppresses natural killer (NK) cell and cytotoxic T-lymphocyte activation; it is expressed on the cell membranes of a wide variety of tumors of neuroectodermal, mesenchymal and epithelial origin and its expression is associated with increased aggressiveness, poor prognosis and resistance.