Biodistribution studies in LS174T tumor bearing nude mice. Biodistribution study of 125I-VG-IgG2κ (■) as compared with 131I-X4 (○) in LS174T tumor bearing nude mice dissected 24 and 72 h after i.v. co-injection. The tissues shown are (from left to right) tumor, liver, kidneys, lung, spleen, heart, muscle, bone, skin, stomach, low bowel, colon, carcass and blood. Results are expressed in terms of %ID/g ± SD.