^(99m)Tc标记卵巢癌单抗片段F(ab')_2放射免疫显像的实验研究

EXPERIMENTAL STUDY OF RADIOIMMUNOIMAGING WITH^(99m)Tc LABELING F(ab’)2 FRAGMENT

目的：为了改进放射免疫显像（ＲＩＩ），进行９９ｍＴｃ标记卵巢癌单克隆抗体ＣＯＣ１８３Ｂ２Ｆ（ａｂ’）２ＲＩＩ的研究。方法：采用无花果酶制备单抗ＣＯＣ１８３Ｂ２片段Ｆ（ａｂ’）２，改进ＳｎＣｌ２法进行９９ｍＴｃ标记片段Ｆ（ａｂ’）２及正常鼠ＩｇＧ（ＮＭＩｇＧ）；９９ｍＴｃＣＯＣ１８３Ｂ２或９９ｍＴｃＮＭＩｇＧ标记物分别经腹腔注入荷人卵巢癌裸鼠体内，１８ｈ进行ＲＩ。显像后测定并计算肿瘤与非肿瘤组织放射性活度比值（Ｔ／ＮＴ）。结果：（１）无花果酶可制备ＣＯＣ１８３Ｂ２单抗片段Ｆ（ａｂ’）２；（２）改进ＳｎＣｌ２法进行９９ｍＴｃ标记Ｆ（ａｂ’）２，标记率达９０％以上；（３）１８ｈ后ＲＩ，可见９９ｍＴｃＣＯＣ１８３Ｂ２组荷瘤裸鼠较９９ｍＴｃＮＭＩｇＧ对照组移植瘤图像清晰，且Ｔ／ＮＴ值明显高。结论：应用片段Ｆ（ａｂ’）２可改善ＲＩＩ。

Objective: To study radioimmunoimaging (RII) by F(ab’)2 of monoclonal antibody COC183B2 with ^(99m)Tc Methods:Monoclonal antibody COC183B2 was digested by ficin to produce F(ab’)2. The F(ab’)2 and normal mouse IgG(NMIgG) labeled with 99mTc by an improved pretinning method were administered into intraperitoneally nude mice bearing human ovary carcinoma, respectively. Imaging by γcamera was obtained at 18 hour postinjection. After RII, the γcounting data of related tissues were measured to calculate the ratio of radioactivity for tumor and nontumor(T/NT). Results:(1)Preparation of F(ab’)2 fragment by ficin digestion showed good immunoactivity retained; (2) The labeling ratio was more than 90% by an improved pretinning method; (3) 18 hours after being administered of ^(99m)Tc COC183B2F(ab’)2, RII showed clear localization of tumor and T/NT ratios were significantly higher than those of the control group (^(99m)Tc NMIgG). Conclusion: ^(99m)Tc COC183B2F(ab’)2 might improve the result of RII.