Objective Tostudythe 131I labeling methods, stability and immunological activity of antiprogastrin-releasing peptide(31-98) single-chain antibody(anti-ProGRP(31-98) scFv).
Methods The anti-Pro-GRP(31-98) scFv was labeled by Chloramine-T method using 131I, and purified by gel column separation method. The labeling efficiency, radiochemical purity and stability were estimated by using paper chromatography. Immunological activity was detected with cell conjugation assay.
Results The labeling efficiency and radiochemical purity of 131I-anti-ProGRP(31-98) scFv were 93.35%and 98.49%, respectively.The radiochemical purity was 94.59%after incubation in water bath at 37℃ for 24h, and still maintained above 90%for 48 h. After incubation with healthy human serum for 48 h, the radiochemical purity was still above 80%.The immunobinding ratios of 131I-anti-ProGRP(31-98) scFv for NCI-H446 cells and A549 cells were 85.36%and 21.02%, respectively.
Conclusions 131I-anti-ProGRP(31-98) scFv not only has high labeling efficiency and radiochemical purity, but also has good stability and keeps good immunological activity.Therefore, it could be a promising agent for radioimmunoimaging and radioimmunotherapy for the malignant tumors which highly express ProGRP.
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