IN-VITRO REACTIVITY AND IN-VIVO BIODISTRIBUTION OF THE MONOCLONAL-ANTIBODY A7 USING HUMAN GASTRIC-CARCINOMA CELL-LINES

The monoclonal antibody (MAb) A7 has been used to treat patients with colorectal or pancreatic carcinoma with encouraging results. We theref ore determined if MAb A7 would also react with gastric carcinoma cell lines. MAb A7 reacted with seven of eight gastric carcinoma cell lines tested. The intensity of the reaction, measured by flow cytometry, wa s equal to that of WiDr (colon) and HPC-YS (pancreas) cell lines. In n ude mice bearing xenografts of the MAb A7-reactive gastric cancer line MKN45, the percentage injected dose of MAb A7 per g of tumour tissue on day 7 was 9.79; this value was 77% of that on day 1. The in vivo tu mour-to-blood ratio of MAb A7 was 2.77 on day 7. Therefore, MAb A7 has long-term retention at binding sites as well as a high probability, h igh intensity and high specificity of reactivity against gastric cance r, which make it an ideal drug carrier for immunotargeted chemotherapy and immunodiagnosis.