A number of syntheses of small magnetic particles permitting the covalent attachment of antibodies will be examined. Changes in magnetic resonance (MR) proton relaxation after magnetic antibodies have bound to cell surface antigens will be utilized to demonstrate the binding of antibody (and magnetic label) to antigens. The magnetic labels investigated will possess the magnetic properties of a crystal (e.g. high magnetic susceptibility), but possess the solution properties of soluble micromolecules (e.g. no setting on prolonged standing). One advantage of attaching antibody to magnetic particles, over the often used approach of derivatizing proteins with chelators, is that far more metal ions can be attached per mole of antibody. Highly magnetic proteins maybe useful agents for immunodirectable MR contrast agents. Key words: image enhancement, contrast agents, magnetic resonance Summary of Potential Commercial Application: The proposed research will lead to the development of a new class of magnetic labels to which antibodies can be attached. The magnetic labels will serve as immunodirectable MR image contrast agents. Immunospecific methods of tumor localization have long been of major research and commercial interest. Unlike radiolabelled antibodies, magnetic labels show no radioactive decay. Centralized manufacture of magnetically labelled antibodies for tumor localization will become possible.
