IMMUNODIRECTABLE MR CONTRAST AGENTS

A NUMBER OF SYNTHESES OF SMALL MAGNETIC PARTICLES PERMITTINGTHE COVALENT ATTACHMENT OF ANTIBODIES WILL BE EXAMINED. CHANGES IN MAGNETIC RESONANCE (MR) PROTON RELAXATION AFTER MAGNETIC ANTIBODIES HAVE BOUND TO CELL SURFACE ANTIGENS WILLBE UTILIZED TO DEMONSTRATE THE BINDING OF ANTIBODY (AND MAGNETIC LABEL) TO ANTIGENS. THE MAGNETIC LABELS INVESTIGATED WILL POSESS THE MAGNETIC PROPERTIES OF A CRYSTAL (E.G., HIGH MAGNETIC SUSCEPTIBILITY)AND THE SOLUTION PROPERTIES OF SOLUBLE MACROMOLECULES (E.G.,NO SETTLING 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. IN ADDITION, UNLIKE RADIOLABELED ANTIBODIES, MAGNETIC LABELS SHOW NO RADIOACTIVE DECAY. HIGHLY MAGNETIC PROTEINS MAY BE USEFUL AGENTS FOR IMMUNODIRECTABLE MR CONTRAST AGENTS.