抗Ⅳ型胶原酶单抗在人肺癌裸鼠移植模型中的免疫显像

背景与目的：基质金属蛋白酶(matrix metalloproteinases,MMPs)在肿瘤生长和转移的多个环节发挥着重要作用,Ⅳ型胶原酶作为MMPs家族的重要成员之一已成为肿瘤研究的新靶点。本文通过荷瘤裸鼠的显像实验,评价抗Ⅳ型胶原酶单克隆抗体3G11的体内特异性分布。方法：用lodogen法将^131I或^125I标记亲和纯化的单抗3G11,ELISA检测标记前后单抗的活性变化。^131I-3G11在3种不同体系(生理盐水,小牛血清,裸鼠血清)中37℃温育,检测体外稳定性。每只正常BALB／c小鼠静脉注入388．5kBq ^125-I3G11,测定单抗的药动学指标。建立人高转移PG肺癌细胞移植肿瘤模型的BALB/c(nu/nu)裸鼠每只静脉注入6．44MBq ^131I-3G11,进行免疫显像。结果：单抗3G11经亲和纯化后纯度大于98％,碘标记使单抗活性降低10％～20％。单抗3G11的体内代谢呈二室模型分布,T1/2α为7．2h,T1/2β为345．2h。^131I-3G11标记物体外72h能基本保持稳定,在荷瘤裸鼠体内72h显像清晰,至120h效果更明显。结论：显像实验证明单抗3G11对肿瘤组织有较好的特异性和亲和性。

Immunoscintigraphy of anti-type IV collagenase monoclonal antibody in nude mice bearing human lung cancer xenograft

BACKGROUND & OBJECTIVE: Matrix metalloproteinases (MMPs)play the important role in many steps of tumor growth and metastasis. Type IV collagenase, which is a key member of MMPs family, has been viewed as a promising target in tumor study. The aim of this study was to evaluate the tumor-specific distribution of the anti-type IV collagenase monoclonal antibody (mAb) 3G11 by radioimaging in tumor-bearing nude mice. METHODS: MAb 3G11 purified by affinity chromatography was labeled with either 131- or 125- iodide by the Iodogen method. Immunoreactivity of mAb 3G11 was determined by ELISA. (131)I-labeled 3G11 was incubated in three different media at 37 Celsius degree and its in vitro stability was tested. Normal BALB/c mice were injected intravenously with 388.5 kBq per mouse of (125)I-labeled 3G11 to explore the pharmacokinetic patterns. The scintigraphic images of human lung carcinoma PG xenografts grown subcutaneously in BALB/c nude mice were made after intravenously administrating of 6.44 MBq per mouse of (131)I-labeled 3G11. RESULTS: MAb 3G11 was more than 98% in purity via affinity purification. The immunoreactivity of mAb 3G11 decreased by approximately 10%-20% after cold iodination. Patterns of blood clearance of mAb 3G11 was defined as two-compartment model, with T(1/2alpha) and T(1/2beta) calculated to be 7.2 h and 345.2 h, respectively. (131)I-labeled 3G11 was almost stable in vitro for 72 h. A clear image of the xenografted tumor was obtained at 72 h, and it further improved at 120 h. CONCLUSION: MAb 3G11 showed high specificity and affinity with tumor tissue through scintiscanning.