Definition

A radioimmunoconjugate composed of a humanized form of the mouse monoclonal antibody JAA-F11 (hJAA-F11) directed against the alpha-O-linked galactose disaccharide and tumor-associated antigen (TAA) Thomsen-Friedenreich (TF) antigen (TF-Ag) labeled with the radioisotope iodine I 124, with potential imaging activity upon positron-emission tomography (PET). Upon administration of iodine I 124 hJAA-F11, the antibody moiety specifically targets and binds to alpha-linked TF-Ag expressed on tumor cells, thereby allowing for the visualization of TF-Ag-expressing tumors upon PET. This may facilitate the assessment of the effectiveness of hJAA-F11. In tumor cells, TF-Ag appears as the disaccharide D-galactose-beta-(1-3)-N-acetyl galactosamine (Gal-beta-(1-3)-GalNAc) that is specifically alpha linked to a serine or a threonine residue on proteins. It is overexpressed on a variety of tumor cells and its expression is associated with tumor cell adhesion, tissue invasion and aggressiveness.