[Preparation of monoclonal antibodies for radioimmunoimaging of xenografted pancreatic cancer].

Monoclonal antibodies (McAb) to pancreatic cancer were developed by fusing SP2/0 cells and splenocytes from Balb/C mouse immunized with Pan-2 cells. The specific binding rate of McAb P1 and McAb P2 were 40.1% and 43.8% respectively when shown by binding radioactivity assay in vitro, which were in sharp contrast with control groups (less than 5%). The biodistribution of radioiodinated McAb P2 was studied by measuring parameters of tumor specific radioactivity in nude mice bearing Pan-2 tumor. The ratios of tumor to non-tumor (T/NT) were all more than 2 at 48-hour. Localization index (LI) of cancer and the ratio of Tumor/Pancreas were 4.05 and 4.16 respectively at 72-hour. So 131I McAbs may be useful for radioimmunoimaging of pancreatic cancer. After intraperitoneal injection of 131I-McAb P2 into tumor-bearing nude mice, imaging of xenograft pancreatic cancer became increasingly distinct with nonspecific background fainting, especially in the period of 72-96 hours. Pancreatic cancer tissues were examined by immunohistochemistry with McAb P2 and revealed strongly positive (86%), in comparison with other tumors and normal tissues. The results demonstrated that clinical radioimmunoimaging of pancreatic cancer was feasible with McAb P2.