SOLID-PHASE LABELING OF MONOCLONAL-ANTIBODIES WITH TC-99M USING 2 BIFUNCTIONAL PHOTOCLEAVABLE REAGENTS

Two photolabile heterobifunctional O-nitrobenzyl reagents were used to modify B72.3 monoclonal antibody followed by immobilization on a soli d support. Antibody was labeled with Tc-99m and then cleaved from the resin on irradiation with light of peak intensity at 365 nm. The antib ody was restored unmodified after cleavage. The labeled product, void of any impurity or free Tc-99m, exhibited compatible imaging quality a nd biodistribution when compared to the same product labeled using sol ution chemistry. This new technique offers the potential of a commerci ally attractive Tc-99m-labeling kit. Although the method was designed from the perspective of Tc-99m-labeling of monoclonal antibodies, it s hould be applicable to any solid phase protein modification.