抗电鳐乙酰胆碱酯酶单克隆抗体2E6的交叉免疫反应性

用乙酰胆碱酯酶（ＡＣｈＥ）偶联的ＡＨＳｅｐｈａｒｏｓｅ４Ｂ免疫亲和层折法提纯了抗丁氏汉结电线ＡＣｈＥ单克隆抗体２Ｅ６（ＩｇＧ１）．用配基亲和层忻法纯化了人脑，人红细胞，牛脑．牛红细胞，比目鱼肌肉及石纹电线电器官的ＡＣｈＥ．用酶抗原免疫测定法及固相免疫测定法观察了２Ｅ６与这些脊椎动物ＡＣｈＥ的交叉免疫反应性．结果显示２Ｅ６与石纹电鳐，人脑．牛脑及比目鱼肌肉ＡＣｈＥ有明显的交叉免疫反应性．说明２Ｅ６针对的抗原决定簇在进化中高度保守．２Ｅ６与人和牛红细胞ＡＣｈＥ及人血清丁酰胆碱酯酶无交叉免疫反应性．２Ｅ６与电鳐ＡＣｈＥ结合后严重地抑制酶对硫代乙酰担碱的催化作用．但２Ｅ６对哺乳类ＡＣｈＥ无抑制作用．推测２Ｅ６针对的抗原决定簇在电鳐ＡＣｈＥ分子上靠近其活性中心．而在其它几个酶分子上则远离活性中心．

Cross immunoreactivity of monoclonal antibody 2E6 toTorpecto acetylcholinesterase

Monoclonal antibody 2E6 (IgG1) toacetylchoiinesterase (AChE) froin electric organs ofNarcine timlei was purified by immunoaffinitychromatography on an AH- Sepharose 4B columncoupled with acetylcholinesterase. Cross iminunoreactivity between 2E6 and acetylcholinesterases fromvanous vertebrate sources was detected. 2E6 exhibitedan intensive immunoreactivity with AChEs froin liuman brain. bovine braui and flounder inuscle. howeverit did neither react with AChEs from human andbovine erythrocytes. nor with butyrylcholinesterasefrom human serum. It implics that the 2E6 directedepitope is highly conserved in the evolution. The bind-ing of 2E6 with Torpedo mariiiorata AChE profoundlyinhibited the enzymatic catalysis of acetylthiocholine,but 2E6 failed to inhibit mammalian AChEs. It sug-gests that the epitope directed by 2E6 probably locatedin the vicinity of the active center on the Torpedomarmorata AChE molecule, and is remote from the ac-tive center on the other vertebrate AChE molecules.