2,3,4,5-TETRAHYDROXY-5-(4-HYDROXYPHENYL)VALERIC ACID - A NEW CLEAVABLE MONOFUNCTIONAL REAGENT FOR MONOCLONAL-ANTIBODY LABELING

The synthesis and preliminar biological assays of a new monofunctional reagent to reversible derivatize monoclonal antibodies is described. This compound, comprising a 1,4-polyiol moiety, is cleavable by means of sodium periodate in mild conditions; moreover it also contains a ph enolic residue suitable for I-125 labelling and a carboxylic group for reaction with epsilon-lysyl amino group of antibodies. These features are suitable to study the monoclonal antibodies cell-internalization process and antigen expression on cell surface. The I-125 labelled rea gent has been coupled to the monoclonal antibody AR-3, an IgG1 directe d toward the CAR-3 antigen widely expressed on human ovarian and color ectal adenocarcinomas. The cleavage capability is tested in different conditions both on reagent and on derivatized MAb. Cell labelling expe riments are performed both on target and untarget cell lines.