111In-CHX-A”-DTPA hu3S193 diabody was analyzed by FPLC for its serum stability properties: A, in 5% human serum albumin at 0 h after incubation; B, in normal human serum at 1 h; and C, 48 h after incubation. 111In-CHX-A”-DTPA hu3S193 diabody was analyzed by FPLC for its serum stability properties: A, in 5% human serum albumin at 0 h after incubation; B, in normal human serum at 1 h; and C, 48 h after incubation. Protein detected at A280 nm is represented by ———, whereas radioactivity measured by gamma counting is represented by ----. B and C, the protein peaks represent thyroglobulin (Mr 669,000; ∼18 min), immunoglobulin (Mr 150,000; ∼24 min), and human serum albumin (Mr 67,000; ∼27.5 min), where 1-min fractions were collected. Kiki Tahtis et al. Clin Cancer Res 2001;7:1061-1072 ©2001 by American Association for Cancer Research