Biodistribution and γ Imaging of ~(125)I-labeled Goat Anti-human IgG Polyclonal Antibody in Nude Mice Bearing Human Colon Cancer Xenografts

The possibility of IgG secreted from tumor cells as a target for radioimmunoimaging and targeted therapy of cancers were investigated.Goat anti-human IgG polyclonal antibody(GAHG) was radioiodinated using Iodogen method,and the in vitro stability and pharmacokinetics were evaluated.The biodistribution and γ imaging of 125I-GAHG were performed in nude mice bearing HT-29 human colon cancer xenografts.125I-GAHG showed good in vitro stability,and its blood clearance was defined as a two-compartment model,with T1/2α and T1/2β were 1.19 h and 43.99 h,respectively.The tumor uptake of 125I-GAHG was higher than that of 125I-labeled normal goat IgG control(125I-GIgG).125I-GAHG showed good tumor retention when injecting via intra-tumor.In the biodistribution study,the highest tumor uptake of 125I-GAHG was 6.71± 2.19 %ID/g at 72 h postinjection and the T/NT increased along with the postinjection time.The results show that 125I-GAHG have good tumor-specific uptake which may provide a novel idea for radioimmunoimaging and targeted therapy of cancers.