靶向巨噬细胞的纳米抗体PET分子探针^(68)Ga-NOTA-Nb119的制备方法

Method of preparing macrophage-targeting nanobody^(68)Ga-NOTA-Nb119 as PET molecular probe

目的用^(68)Ga标记纳米抗体Nb119和NbBCⅡ10,制备靶向巨噬细胞的PET探针。方法将抗Vsig4纳米抗体Nb119和同型对照抗体BCⅡ10与螯合剂NOTA共孵育,纯化后分别与^(68)Ga进行标记。通过SDS-PAGE、MALDI-TOF方法对NOTA-Nb119进行鉴定,利用Radio-HPLC检测^(68)Ga标记后NOTA-Nb119和NOTA-BCⅡ10放化纯度。结果SDS-PAGE结果显示,成功标记的NOTA-Nb119的泳道条带比未标记纳米抗体条带出现明显的滞后性,证明标记后产物分子量变大,纳米抗体被NOTA成功修饰。^(68)Ga能成功标记纳米抗体Nb119和BCⅡ10,经Radio-HPLC检测,^(68)Ga标记的NOTA-Nb119和NOTA-BCⅡ10放化纯度均高于90%,且可稳定存在。结论^(68)Ga标记的两种纳米抗体均具有高放化纯度和高稳定性,说明本研究可推广适用于其他纳米抗体的修饰和标记,为在PET中使用纳米抗体作为分子影像探针提供了切实可行的方法。

Objective To prepare positron emission computed tomography(PET)molecular probes targeting macrophages using Nb119 and BCⅡ10 labeled with ^(68)Ga nuclide.Methods To explore the labeling conditions of nanobodies with ^(68)Ga nuclides,first,the anti-Vsig4 nanobody Nb119 and isotype control antibody BCⅡ10 were incubated with NOTA and then purified to obtain the chelating agent-modified NOTA-Nb119 and NOTA-BCⅡ10.The NOTA-Nb119 and NOTA-BCⅡ10 were further incubated with ^(68)Ga.Finally,NOTA-Nb119 was identified by SDS-PAGE and MALDI-TOF methods,and the radiochemical purity was detected by radio-HPLC.Results The results of SDS-PAGE showed that the lanes of the successfully labeled NOTA-Nb119 had apparent hysteresis than the unlabeled nanobody band,which proved that the molecular weight of the labeled product was increased and NOTA successfully modified the nanobody.Subsequently,^(68)Ga nuclides could successfully label Nb119 and BCⅡ10.According to radio-HPLC detection,the radiochemical purity of NOTA-Nb119 and NOTA-BCⅡ10 labeled with ^(68)Ga was greater than 90%and remained stable.Conclusion ^(68)Ga-labeled nanobodies have high radiochemical purity and high stability,indicating that this study can be applied to other nanobodies for modification and labeling and provides a practical and feasible method for the preparation of PET using nanobodies.