Direct Labeling of Anti-hepatoma Monoclonal Antibody Fragment With ~(188) Re

A two steps method of direct labeling of anti human hepatoma monoclonal antibody fragment HAb18 is investigated. Stannous chloride and sodium bisukfite is used as reducing agents of 188 ReO 4 - and antibody fragment respectively. The effects of reduction conditions of 188 ReO 4 - biothiol and antibody on the labeling efficiency is evaluated in detail. The results show that labeling efficiency, numbers of thiol and immunoreactive fraction reached up to 85%~93%, 2.4/molecule and 0.91 respectively. The stability of labeling compounds keep much better in vitro. The biodistribution in normal and nude mice demonstrates that 188 Re Fab′ ( 188 Re F(ab′) 2) is cleared rapidly from the blood and mainly from kidney, and tumor has significant uptake.