Abstract: PREPARATION OF 35SMAb HEPAMA1Zhou Zhentang\ Zhuang Daoling\ Wu Yuanfang\ Zhang YulongHe Zhanjun\ Liu Guanfu\ Yao Fuzeng(Shanghai Institute of Nuclear Research, the Chinese Academy of Sciences, 201800)ABSTRACTMonoclonal antibody Hepama1（MAb Hepama1) against human hepatoma is labelled with 35S by the carbodiimine method. The 35Ssulfanilic acid is transferred from 35Saniline sulfate which is synthesized by both H235SO4 and aniline, and then, it is connected to the MAb Hepama1. The resultant labelled MAb Hepama1 retains immunoreactivity and had a maximum specific activity of 51.8 GBq/g and a radiochemical purity of >95%. The radiochemical yield are 27% and 45%, according to the primary activity of H235SO4 and 35Ssulfanilic acid respectively. It is used as a radioimmunotherapy agent with a strong cytotoxic and tumorinhibitory effect in the Hepamabearing nude mice.Key words 35S monoclonal antibody Hepama1 against human hepatoma 35SMAb Hepama1 preparation