An anti-MUC1 monoclonal antibody for radioimmunoscintigraphy of breastcancer: indirect labeling of antibody via the HYNIC with 99mTc; in vitro and invivo studies of new radiopharmaceutical

摘要

Radioimmunoscintigraphy using Mabs carrying radionuclides is a promising approach towardrnimproving early diagnosis of cancer. The PR81 is a new murine anti-MUC1 Mab that reacts strongly with thernmembrane extracts of several human breast cancerous tissues. This study was performed to develop an indirectrnlabeling of this antibody via the succinimidyl 6-hydrasino nicotinate hydrochloride (HYNIC) with 99mTc in orderrnto use the new preparation in immunoscintigraphy studies of BALB/c mice bearing breast tumor xenografts. Arn20 molar excess of freshly dissolved HYNIC was added to a solution of the Ab. The solution was stirred for 5 hrrnat room temperature followed by dialysis against citrate buffer overnight. The resulting conjugate was labeledrnwith 99mTc using tricine as a co-ligand. The labeling efficiency determined by ITLC was 89.2%±4.7.rnRadiocolloides measured by cellulose nitrate electrophoresis were 3.4%±0.9. In vitro stability of labeled productrnwas determined at room temperature by ITLC and in human serum by gel filtration chromatography (FPLC)rnwere 85.3%±3.6 and 78.6%±5.7 over 24 hr respectively. The integrity of labeled Mab was checked by means ofrnSDS-PAGE and no significant fragmentation was seen. The results of cell-binding studies showed that bothrnlabeled and unlabeled PR81 were able to compete for binding to MCF 7 cells. Biodistribution studies werernperformed in normal BALB/c mice at 4 and 24 hr post-injection and no important accumulation was seen in vitalrnorgans. The tumor imaging was performed in female BALB/c mice with breast tumor xenografts at 24 hr afterrnthe radiopharmaceutical injection demonstrated definite localization of the preparation at the site of tumors withrnhigh sensitivity. These findings show that the new preparation can be considered as a promising candidate forrnimaging of human breast cancer.