Biodistribution of monoclonal antibody A7 and its F(ab')2 fragment in athymic nude mice bearing human pancreatic carcinoma.

Xenografts of a human pancreatic carcinoma cell line, HPC-YS, which reacted with the monoclonal antibody (MAb) A7, were used to investigate the in vivo localization of radioiodinated MAb A7 after intraperitoneal injection. MAb A7 localized to the tumor 4 days and 8 days after injection with a tissue/blood ratio of 1.45 +/- 0.18 and 2.04 +/- 0.20, respectively. The accumulation of MAb A7 in the tumor was 5%/g and 3.3%/g of the injected dose on day 4 and on day 8, respectively. In contrast, the F(ab')2 fragment of MAb A7 localized to the tumor 4 days after intravenous injection with a tissue/blood ratio of 14.2. The accumulation of the F(ab')2 fragment in the tumor was 1.2%/g of the injected dose. These results suggested that MAb A7 might be a suitable carrier of anticancer drugs for immunotargeting chemotherapy and that the F(ab')2 fragment might be potentially useful for the immunodetection of human pancreatic carcinomas.