Objective Progastrin-releasing peptide(31-98)(ProGRP(31-98)is a specific tumor marker in patients with small cell lung cancer (SCLC). E-B5 antibody against ProGRP(31-98) was produced by China Institute for Radiation Protection. The aim of this study was to explore the 131I labeling methods, stability, immunological activity and biological distribution pattern of E-B5 antibody against ProGRP(31-98). Methods Chloramine-T method was used for 131I labeling E-B5 antibody. Labeling efficiency, radiochemical purity and stability were estimated by using paper chromatography method. Immunological activity of 131I-E-B5 was detected with cell conjugation assay. After healthy Kunming mice were injected with 131I-E-B5 antibody through tail veil, the biodistribution and pharmacokinetics of 131l-E-B5 antibody in healthy Kunming mice were studied. Continuous images of the nude mice beating SCLC were carried out at different time points af-ter injection of 131I-E-B5 antibody. Continuous variables were expressed as x±s and compared by t-test with SPSS 13.0 software. Results The labeling efficiency and radiochemical purity of131I-E-B5were 90.8%, 99.28%, respectively. The radiochemical purity still maintained above 70% after incubation in water bath at 37℃ for 24 h. After incubation with healthy serum for 24 h, the radiochemical purity still reached 68.1%. The immunobinding ratios were 71.6% and 33.2% for NCI-H446 cells and A549 cells respective-ly. The in vivo distribution and elimination of 131I-E-B5 antibody were consistent with a first-order and two-compartment model, t1/2α=0.2 h, t1/2α= 8.35 h. The metabolism of 131I-E-B5 antibody mainly depended on liver and kidney and with rapid elimination in blood. Condusions 131I-E-B5 antibody not only has high la-beling efficiency and radioehemical purity, but also has good stability and keeps good immunological activi-ty. 131I-E-B5 is a promising agent of radioimmunoimaging and radioimmunotherapy of SCLC.%目的 研究抗胃泌素释放肽前体(ProGRP)片段ProGRP(31-98)单克隆抗体E-B5的131I标记方法 以及标记抗体在正常小鼠体内的生物分布特点.方法 利用流式细胞仪检测人小细胞肺癌NCI-H446细胞株和肺腺癌A549细胞株(对照)ProGRP表达,对人小细胞肺癌组织切片进行免疫组织化学染色分析.采用氯胺T法进行131I-E-B5标记,利用纸层析法测定其标记率、放化纯和稳定性,细胞结合分析法测定标记抗体的免疫活性.将131I-E-B5注入正常昆明小鼠体内,对药物体内分布及药物代谢动力学进行研究.对荷小细胞肺癌裸鼠模型进行131I-E-B5放射免疫显像,观察移植瘤的显影情况.采用SPSS 13.0软件处理数据.结果 流式细胞仪测得处于对数生长期的NCI-H446、A549细胞ProGRP表达率分别为89%和12%,人小细胞肺癌组织切片免疫组织化学染色见明显的E-B5阳性细胞分布,并显示ProGRP表达在肿瘤细胞的细胞质内.131I-E-B5标记率为90.8%,放化纯为99.28%,在37℃水浴箱中放置24 h后放化纯仍>70%,和健康人血清充分混合后放置24 h放化纯为68.1%,对NCI-H446和A549的免疫结合率分别为71.6%和33.2%.131I-E-B5在小鼠体内过程符合一级血药动力学二室模型,t1/2α=0.2 h,t1/2β=8.35 h,在体内主要通过肝和肾代谢.注射131I-E-B5后72和96 h小细胞肺癌裸鼠移植瘤体显影最清晰.结论 NCI-H446细胞株及人小细胞肺癌组织高表达ProGRP,E-B5对小细胞肺癌有较好的靶向作用.131I-E-B5标记率及放化纯高,在体内外有很好的稳定性,标记后的E-B5仍然保持着良好的免疫活性,对小细胞肺癌放免显像和治疗有潜在的应用前景.
展开▼
