大肠癌相关抗原CA－Hb_3的纯化及其在胃肠道肿瘤血清学诊断中的应用

PURIFICATION AND APPLICATION OF COLORECTAL CANCER ASSOCIATED ANTIGEN(CA一Hb3)

用一株鼠抗人大肠癌单克险抗体Ｈｂ３，纯化后与溴化氰活化的Ｓｅｐｈａｒｏｓｅ４Ｂ偶联制各免疫吸附柱。用免疫亲和层析法从大肠癌细胞株ＨＲＴ－１８细胞提取液中纯化相应抗原ＣＡ－Ｈｂ３。经多种实验证实ＣＡ－Ｈｂ３是一种新的大肠癌相关糖蛋白抗原、分子量约为６５Ｋｄ．以此纯化抗原作参考标准，用ＳａｎｄｗｉｃｈＥＬＩＳＡ方法检测大肠癌及消化迟其他肿瘤患者血清ＣＡ－Ｈｂ３水平。结果表明，ＣＡ－Ｈｂ３对胃肠运肿瘤诊断的敏感性和特异性较高，具有一定的临床价值。

The murine monoclonal antibody Hb3 against human colorectal cancer was purified bypassing precipitation of ammonium sulfate a SephacrylS-300 column.The McAb Hb3 wascovalently binded with CNBr-activated Sepharose 4B for preparation of immuno-adsorptioncolumn,By means of immunoaffinity chromatography,the Hb3 corresponding antigen(CA-Hb3)was purified from the crude soluble antigen of colonic cell lines, HRT-18. The eluantwas 3 mol potassium thiocyanate,one band corresponding to molecular weight of 65 Kd wasrecognized in western blotting and immunostaining,CA-Hb3 resisted heat-treatment at70℃ for 30 min or 100℃ for 10min,It did not react with Hb3 after periodate oxidation, butit did react with Hb3 after being treated by neuraminidase.The resuIts suggest that CAHb3 is a new colorectal cancer associated glycoprotein。A Sandwich ELISA was extablishedto measure serum CA-Hb3 level in patients with gastrointestinal cancer。The resuIts indicat-ed that the positive rate of colorectal cancer,stomach carcinoma and benign digestive diseasewas 68.9%(62/90),56.7%(17/30)and 11.9%(7/59),respectively. The findings demon-strate that CA-Hb3 is a sensitive,specific and noveI tumour marker and may be a potentialvaluable marker in serodiagnosis of gastrointestinal carcinoma.