IMMUNOAFFINITY PURIFICATION WITH ANTI-ID ANTIBODIES

ONE OF THE PRIMARY LIMITATIONS IN THE USE OF RADIOIMMUNOSCINTIGRAPHIC TECHNIQUES TO DETECT TUMORS CLINICALLY HAS BEEN THE DIFFICULTY IN ACHIEVING HIGH TUMOR-TO-NORMAL-TISSUE RATIOS OF BOUND RADIOACTIVITY. PART OF THIS DIFFICULTY ARISES FROM THE FACT THAT A SIGNIFICANT PROPORTION OF MONOCLONAL ANTIBODIES (MABS) ARE INACTIVATED DURING RADIOLABELING PROCEDURES AND SUCH MABS, WHEN INJECTEDINTRAVENOUSLY, LOCALIZE NONSPECIFICALLY IN NORMAL TISSUES. THIS PROJECT ADDRESSES THE PROBLEM THROUGH THE DEVELOPMENT OF AN INNOVATIVE METHOD FOR EFFECTIVELY SEPARATING ANTIBODIES DAMAGED DURING RADIOLABELING PROCEDURES FROM THOSE RETAINING THEIR ORIGINAL AFFINITY AND SPECIFICITY. PRELIMINARY STUDIES INDICATE THAT ANTI-IDIOTYPIC (ANTI-ID) MABS RECOGNIZING THE COMBINING SITES OF ANTIMELANOMA MABS CAN BE PREPARED AS AFFINITY MATRICES TO PURIFY THE ANTIMELANOMA MABS AFTER RADIOLABELING PROCEDURES. THE IMMUNOREACTIVITY, SPECIFICITY, AFFINITY, AND TUMOR-TO-TISSUE RATIOS OF IN-111-LABELED ANTIMELANOMA MABS WILL BE ASSAYED BEFORE AND AFTER IMMUNOAFFINITY PURIFICATION WITH ANTI-ID MABS. IF THE METHOD IS EFFECTIVE,IT MAY BE POSSIBLE TO INCREASE THE SENSITIVITY OF TUMOR DETECTION BY RADIOIMMUNOSCINTIGRAPHY.