This study describes the radioiodination of an antibody specific to the vascular endothelial growth factor (VEGF), VG76e, with [124I]iodine to obtain a novel PET tracer for measurement of angiogenesis. In vitro binding assays showed a significantly higher immunoreactive fraction with the protein labelling reagent N-succinimidyl 3-(4-hydroxy-5-[125I]iodophenyl) propionate ([125I]Bolton–Hunter reagent, [125I]I-SHPP) (34.0±4.0%) as compared with N-succinimidyl 3-[125I]iodobenzoate (10.9±6.4%) or direct radioiodination using [125I]iodide and IodoGen (3.1±3.0%). Consequently, the cyclotron–produced positron–emitting [124I]iodine (T1/2=4.2 days) was employed to prepare [124I]I-SHPP. Using an improved radioiodination methodology, [124I]I-SHPP was prepared from sodium [124I]iodide with IodoGen at pH 6.5. The [124I]Bolton–Hunter reagent was isolated with 25–58% (n=3) radiochemical yield and 88–95% (n=3) radiochemical purity by the conventional extraction procedure. The conjugate of VG76e with [124I]I-SHPP was prepared with 17–18% (n=3) labelling efficiency and 98% radiochemical purity. The immunoreactive fraction was determined to be 33.5% (n=2). Copyright © 2002 John Wiley & Sons, Ltd.
本研究介绍了用[124I]
碘对血管内皮生长因子(V
EGF)特异性
抗体 VG76e 进行放射性
碘化,以获得一种用于测量血管生成的新型 PET 示踪剂。体外结合试验显示,与蛋白质标记试剂 N- succinimidyl 3-(4-hydroxy-5-[125I]iodophenyl) propionate([125I]Bolton-Hunter 试剂,[125I]I-SHPP)相比,免疫反应率明显更高(34.0±4.0%),而 3-[125I]
碘苯甲酸 N-琥珀
酰亚胺酯(10.9±6.4%)或使用[125I]
碘化物和 IodoGen 进行直接放射性
碘化(3.1±3.0%)。因此,回旋加速器产生的正电子发射[124I]
碘(T1/2=4.2 天)被用来制备[124I]I-SHPP。利用改进的放射性
碘化方法,在 pH 值为 6.5 的条件下,用 IodoGen 从[124I]
碘化钠制备出[124I]I-SHPP。通过传统的萃取程序分离出[124I]Bolton-Hunter试剂,其放射
化学收率为25-58%(n=3),放射
化学纯度为88-95%(n=3)。VG76e与[124I]I-SHPP共轭物的制备过程中,标记效率为17-18%(n=3),放射
化学纯度为98%。经测定,免疫反应部分占 33.5%(n=2)。Copyright © 2002 John Wiley & Sons, Ltd. All Rights Reserved.