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目的为简化抗血小板P 选择素鼠/人嵌合单克隆抗体SZ 51/Hu的99mTc标记过程 ,并提高其99mTc标记效率 ,利用金属硫蛋白(MT)可与金属稳定结合的特点 ,通过基因工程的手段制备融合蛋白SZ 51/Hu MT。方法构建了SZ 51/Hu与MT的重组表达载体 ,并在小鼠骨髓瘤细胞Sp2/0中进行了目的融合蛋白的表达。结果该融合蛋白在Sp2/0细胞中的表达量为3mg/L。对融合蛋白的各项性质分析表明 ,该融合蛋白的相对分子质量(Mr)为180000 ,且具有双向结合的特异性 :即一方面保持了SZ 51与活化血小板P 选择素的特异结合能力 ;另一方面又具有MT高效结合金属的特性。99mTc标记研究表明 ,该分子不需预处理即可被99m Tc直接标记 ,标记率可达79 %。结论获得具有双向结合特异性的融合蛋白SZ 51/Hu MT ,为研制新型血栓导向显像剂开辟了新途径。
Objective To simplify the 99mTc labeling of anti-platelet P-selectin murine / human chimeric monoclonal antibody SZ 51 / Hu and improve its 99mTc labeling efficiency. By using the characteristic of metallothionein (MT) binding to metal stably, The fusion protein SZ 51 / Hu MT was prepared. Methods The recombinant expression vector of SZ 51 / Hu and MT was constructed and the fusion protein was expressed in mouse myeloma cells Sp2 / 0. Results The expression level of this fusion protein in Sp2 / 0 cells was 3 mg / L. The analysis of the properties of the fusion protein showed that the relative molecular mass (Mr) of the fusion protein was 180,000 and the specificity of the two-way binding was maintained: on the one hand, the specific binding capacity of SZ 51 to activated P-selectin was maintained; On the one hand, it has the characteristics of MT combined with metal efficiently. 99mTc labeling study showed that the molecule can be directly labeled with 99mTc without pretreatment, labeling rate of up to 79%. Conclusion The fusion protein SZ 51 / Hu MT with bidirectional binding specificity was obtained, which opened up a new way for the development of new thrombotic imaging agents.