IMMUNOREACTIVITY, STABILITY, PHARMACOKINETICS AND BIODISTRIBUTION OF A MONOCLONAL-ANTIBODY TO HUMAN LEUKEMIC B-CELLS AFTER 3 DIFFERENT METHODS OF RADIOIODINATION

Dal B02, a murine monoclonal antibody against human chronic lymphocyti c leukemia (CLL) was radioiodinated using chloramine T (Chl.T), Bolton -Hunter (B-H) or N-succinimidyl-p-iodobenzoate (PIB). The preparations had comparable radiochemical purity (>97%) and immunoreactive fractio n (65-80%) but the Chl.T-based product was most susceptible to deiodin ation and loss of immunoreactivity. After i.v. injection into CLL-xeno grafted nude mice, the preparations had identical patterns of clearanc e from the blood but the PIB-based product led to more radioactivity i n liver and spleen and less in the thyroid compared to the other prepa rations. The Chl.T-based product showed loss of immunoreactivity in ci rculation and less tumor-localized radioactivity 168 h after administr ation. The differences between the B-H-based and PIB-based products we re less impressive than between PIB-based and Chl.T-based products.