ABSTRACT
Objective To study the biodistribution of anti-HER-2/neu monoclonal antibody Herceptin labeled by 131I(131I-Herceptin) in healthy KM mice and nude mice bearing human ovarian cancer xenografts and radioimmunoimaging (RII) of the nude xenografts-bearing mice.Methods 131I-Herceptin was prepared using Iodogen method.The labeling efficiency, radiochemical purity, stability and immunocompetence were measured.The percentage activity of injection dose per gram of tissue (%ID/g) and the radioactivity ratio of tumor to non-tumor tissue (T/NT) were calculated for each time point.The optimal time for imaging was investigated by comparing the 131I-Herceptin SPECT for the nude mouse models bearing ovarian cancer xenografts at different time points.Results The labeling efficiency and radiochemical purity of 131I-Herceptin were 89.8% and 98.4%, respectively.The labeling was stable and had good immunocompetence.131 I-Herceptin was cleared rapidly mainly through liver, spleen and kidneys, consistent with first order two-compartment model.The uptake of 131I-Herceptin in the tumors bearing human SKOV-3 xenografts was much higher than that in nontumor tissue.The% ID/g was 18.08 in the tumor at 24 h post injection.The T/NT ratio increased with time and was 27.27 at 72 h post injection.The tumors in nude mice bearing SKOV-3 xenografts could be visualized on 131I-Herceptin SPECT imaging 2 h post injection; definitely identiffed 48 h post injection and the radioactivity ratio of tumor to contralateral tissue was 11.44 at 120 h post injection.However, the tumor in nude mice bearing HO-8910 xenografts did not show abnormal uptake of 131 I-Herceptin at each time point.Conclusions 131 I-Herceptin is a good radiopharmaceutical targeting SK-OV-3 xeuografts and it may be useful in imaging carcinoma of ovary and target therapy of its metastases with high HER-2/neu expression.