METHOD
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INSTRUCTIONS
酶联(lian)免疫吸附(fu)测(ce)定(ding)enzyme linked immunosorbent assay(简写(xie)ELISA)指将(jiang)可溶性(xing)(xing)的(de)抗(kang)(kang)原(yuan)或抗(kang)(kang)体(ti)结(jie)合到(dao)聚苯乙烯等固(gu)相载体(ti)上(shang), 利(li)用抗(kang)(kang)原(yuan)抗(kang)(kang)体(ti)结(jie)合专一性(xing)(xing)进行免疫反应的(de)定(ding)性(xing)(xing)和定(ding)量检测(ce)方(fang)法。
METHOD
定(ding)性(xing)(xing)测(ce)定(ding)的(de)结果判(pan)断是(shi)(shi)对受(shou)检标本中(zhong)是(shi)(shi)否含有(you)待测(ce)抗(kang)原或(huo)抗(kang)体(ti)作出(chu)"有(you)"或(huo)"无"的(de)简单回答,分别用"阳(yang)性(xing)(xing)"、"阴性(xing)(xing)"表示(shi)(shi)。 "阳(yang)性(xing)(xing)"表示(shi)(shi)该(gai)标本在(zai)该(gai)测(ce)定(ding)系统中(zhong)有(you)反应(ying)(ying)(ying)。"阴性(xing)(xing)"则为无反应(ying)(ying)(ying)。用定(ding)性(xing)(xing)判(pan)断法也可得到半定(ding)量结果,即用滴度(du)来表示(shi)(shi)反应(ying)(ying)(ying)的(de)强度(du), 其实质仍是(shi)(shi)一个定(ding)性(xing)(xing)试验。在(zai)这(zhei)(zhei)种半定(ding)量测(ce)定(ding)中(zhong),将标本作一系列(lie)稀(xi)释后进行试验,呈阳(yang)性(xing)(xing)反应(ying)(ying)(ying)的(de)最高稀(xi)释度(du)即为滴度(du)。 根据滴度(du)的(de)高低(di),可以(yi)判(pan)断标本反应(ying)(ying)(ying)性(xing)(xing)的(de)强弱,这(zhei)(zhei)比观察不稀(xi)释标本呈色(se)的(de)深浅(qian)判(pan)断为强阳(yang)性(xing)(xing)、弱阳(yang)性(xing)(xing)更(geng)具定(ding)量意义。
在(zai)间(jian)接(jie)法(fa)和夹心法(fa)ELISA中,阳性孔(kong)(kong)呈色深于(yu)阴性孔(kong)(kong)。在(zai)竞争(zheng)法(fa)ELISA中则相反,阴性孔(kong)(kong)呈色深于(yu)阳性孔(kong)(kong)。
ELISA操(cao)作(zuo)(zuo)步骤(zhou)复杂(za),影响反应因素较(jiao)多,特别是固相(xiang)载(zai)体的(de)包被(bei)难达到各个体之间的(de)一(yi)(yi)致(zhi),因此在(zai)定(ding)量测(ce)(ce)定(ding)中(zhong)(zhong)(zhong),每批(pi)测(ce)(ce)试均须用(yong) 一(yi)(yi)系列(lie)不同(tong)浓(nong)度(du)(du)(du)(du)(du)的(de)参考标(biao)(biao)准(zhun)(zhun)品在(zai)相(xiang)同(tong)的(de)条件下制(zhi)(zhi)作(zuo)(zuo)标(biao)(biao)准(zhun)(zhun)曲(qu)(qu)(qu)线(xian)(xian)(xian)。测(ce)(ce)定(ding)大(da)分子(zi)量物质(zhi)的(de)夹心法ELISA,标(biao)(biao)准(zhun)(zhun)曲(qu)(qu)(qu)线(xian)(xian)(xian)的(de)范围一(yi)(yi)般较(jiao)宽, 曲(qu)(qu)(qu)线(xian)(xian)(xian)最(zui)高点的(de)吸光(guang)度(du)(du)(du)(du)(du)可接(jie)近2.0,绘制(zhi)(zhi)时常用(yong)半(ban)对数(shu)值(zhi)(zhi),以(yi)检测(ce)(ce)物的(de)浓(nong)度(du)(du)(du)(du)(du)为横坐标(biao)(biao),以(yi)吸光(guang)度(du)(du)(du)(du)(du)为纵坐标(biao)(biao),将各浓(nong)度(du)(du)(du)(du)(du)的(de)值(zhi)(zhi)逐点连接(jie), 所得曲(qu)(qu)(qu)线(xian)(xian)(xian)一(yi)(yi)般呈(cheng)(cheng)S形(xing),其(qi)(qi)头(tou)、尾(wei)部曲(qu)(qu)(qu)线(xian)(xian)(xian)趋于平坦(tan),中(zhong)(zhong)(zhong)央较(jiao)呈(cheng)(cheng)直线(xian)(xian)(xian)的(de)部分是最(zui)理想的(de)检测(ce)(ce)区域。测(ce)(ce)定(ding)小(xiao)分子(zi)量物质(zhi)常用(yong)竞争法, 其(qi)(qi)标(biao)(biao)准(zhun)(zhun)曲(qu)(qu)(qu)线(xian)(xian)(xian)中(zhong)(zhong)(zhong)吸光(guang)度(du)(du)(du)(du)(du)与受检物质(zhi)的(de)浓(nong)度(du)(du)(du)(du)(du)呈(cheng)(cheng)负相(xiang)关。标(biao)(biao)准(zhun)(zhun)曲(qu)(qu)(qu)线(xian)(xian)(xian)的(de)形(xing)状因试剂盒所用(yong)模式的(de)差别而略有不同(tong)。ELISA测(ce)(ce)定(ding)的(de)标(biao)(biao)准(zhun)(zhun)曲(qu)(qu)(qu)线(xian)(xian)(xian)注意图中(zhong)(zhong)(zhong) 横坐标(biao)(biao)为对数(shu)关系,这(zhei)更(geng)有利于测(ce)(ce)定(ding)系统的(de)表(biao)达。
细(xi)(xi)胞在发生凋亡(wang)(wang)时,会激活(huo)一些DNA内切(qie)酶,这(zhei)些内切(qie)酶会切(qie)断核(he)小体间的(de)(de)(de)基因组(zu)DNA。细(xi)(xi)胞凋亡(wang)(wang)时抽提DNA进(jin)(jin)行(xing)(xing)电泳检(jian)测(ce)(ce), 可以发现(xian)180-200bp的(de)(de)(de)DNA ladder。基因组(zu)DNA断裂时,暴露的(de)(de)(de)3’-OH可以在末端脱氧核(he)苷酸转移(yi)酶(Terminal Deoxynucleotidyl Transferase, TdT) 的(de)(de)(de)催(cui)化下加上荧光(guang)素 (FITC) 标记的(de)(de)(de)dUTP (fluorescein-dUTP) ,从(cong)而可以通过荧光(guang)显微镜(jing)或流式细(xi)(xi)胞仪(yi)进(jin)(jin)行(xing)(xing)检(jian)测(ce)(ce), 这(zhei)就是(shi)TUNEL (TdT-mediated dUTP Nick-End Labeling) 法检(jian)测(ce)(ce)细(xi)(xi)胞凋亡(wang)(wang)的(de)(de)(de)原理。