
紫外光激發熒光物質放射熒光示意圖
免疫熒光實驗的主要步驟包括細胞片製備、固定及通透(或稱為透化)、封閉、抗體孵育及熒光檢測等。細胞片製備(通俗的說法是細胞爬片)是shi免mian疫yi熒ying光guang實shi驗yan的de第di一yi步bu,細xi胞bao片pian的de質zhi量liang對dui實shi驗yan的de成cheng敗bai至zhi關guan重zhong要yao,原yuan因yin很hen簡jian單dan,如ru果guo發fa生sheng細xi胞bao掉diao片pian,一yi切qie都dou無wu從cong談tan起qi。這zhe一yi步bu關guan鍵jian的de是shi玻bo片pian(Slides or Coverslips)的(de)處(chu)理(li)以(yi)及(ji)細(xi)胞(bao)的(de)活(huo)力(li),有(you)人(ren)根(gen)據(ju)成(cheng)功(gong)經(jing)驗(yan)總(zong)結(jie)出(chu)許(xu)多(duo)有(you)益(yi)的(de)細(xi)節(jie)或(huo)小(xiao)竅(qiao)門(men),非(fei)常(chang)值(zhi)得(de)借(jie)鑒(jian)。固(gu)定(ding)和(he)通(tong)透(tou)步(bu)驟(zhou)最(zui)重(zhong)要(yao)的(de)是(shi)根(gen)據(ju)所(suo)研(yan)究(jiu)抗(kang)原(yuan)的(de)性(xing)質(zhi)選(xuan)擇(ze)適(shi)當(dang)的(de)固(gu)定(ding)方(fang)法(fa),合(he)適(shi)的(de)固(gu)定(ding)劑(ji)和(he)固(gu)定(ding)程(cheng)序(xu)對(dui)於(yu)獲(huo)得(de)好(hao)的(de)實(shi)驗(yan)結(jie)果(guo)是(shi)非(fei)常(chang)重(zhong)要(yao)的(de)。免(mian)疫(yi)熒(ying)光(guang)中(zhong)的(de)封(feng)閉(bi)和(he)抗(kang)體(ti)孵(fu)育(yu)與(yu)其(qi)它(ta)方(fang)法(fa)(如ELISA或Western Blot)zhongdexiangtongbuzhoushileiside,zuizhongyaodequbiezaiyumianyiyingguangshiyanzhongyaoyongdaoyingguangkangti,yincibixujinjibiguangcaozuo,ciwaikangtinongdudexuanzekenenggengjiaguanjian。zuihouxuyaozhuyideshi,biaojihaoyingguangdexibaopianyingjinzaoguancha,huozheyongfengpianjifengpianhouzai4℃或-20℃避光保存,以免因標記蛋白解離或熒光減弱而影響實驗結果。
由於操作步驟比較多,同時在分析結果時無法像WB那(na)樣(yang)可(ke)以(yi)根(gen)據(ju)分(fen)子(zi)量(liang)的(de)大(da)小(xiao)區(qu)分(fen)非(fei)特(te)異(yi)性(xing)識(shi)別(bie),所(suo)以(yi)要(yao)得(de)到(dao)一(yi)個(ge)完(wan)美(mei)的(de)免(mian)疫(yi)熒(ying)光(guang)實(shi)驗(yan)結(jie)果(guo),除(chu)了(le)需(xu)要(yao)高(gao)質(zhi)量(liang)的(de)抗(kang)體(ti),以(yi)及(ji)對(dui)實(shi)驗(yan)條(tiao)件(jian)進(jin)行(xing)反(fan)複(fu)優(you)化(hua)外(wai),還(hai)必(bi)須(xu)設(she)立(li)嚴(yan)謹(jin)的(de)實(shi)驗(yan)對(dui)照(zhao)。總(zong)之(zhi),免(mian)疫(yi)熒(ying)光(guang)實(shi)驗(yan)從(cong)細(xi)胞(bao)樣(yang)品(pin)處(chu)理(li)、固定、封閉、抗體孵育到最後的封片及觀察拍照,每步都非常關鍵,需要嚴格控製實驗流程中每個步驟的質量,才能最終達到你的實驗目的。
基本實驗步驟:
(1) 細(xi)胞(bao)準(zhun)備(bei)。對(dui)單(dan)層(ceng)生(sheng)長(chang)細(xi)胞(bao),在(zai)傳(chuan)代(dai)培(pei)養(yang)時(shi),將(jiang)細(xi)胞(bao)接(jie)種(zhong)到(dao)預(yu)先(xian)放(fang)置(zhi)有(you)處(chu)理(li)過(guo)的(de)蓋(gai)玻(bo)片(pian)的(de)培(pei)養(yang)皿(min)中(zhong),待(dai)細(xi)胞(bao)接(jie)近(jin)長(chang)成(cheng)單(dan)層(ceng)後(hou)取(qu)出(chu)蓋(gai)玻(bo)片(pian),PBS洗兩次;對懸浮生長細胞,取對數生長細胞,用PBS離心洗滌(1000rpm,5min)2次,用細胞離心甩片機製備細胞片或直接製備細胞塗片。
(2) 固定。根據需要選擇適當的固定劑固定細胞。固定完畢後的細胞可置於含疊氮納的PBS中4℃保存3個月。PBS洗滌3×5 min.
(3) 通透。使用交聯劑(如多聚甲醛)gudinghoudexibao,yibanxuyaozaijiarukangtifuyuqian,duixibaojinxingtongtouchuli,yibaozhengkangtinenggoudaodakangyuanbuwei。xuanzetongtoujiyingchongfenkaolvkangyuandanbaidexingzhi。tongtoudeshijianyibanzai5-15min.通透後用PBS洗滌3×5 min.
(4) 封閉。使用封閉液對細胞進行封閉,時間一般為30min.
(5) 一抗結合。室溫孵育1h或者4℃過夜。PBST漂洗3次,每次衝洗5min.
(6) 二抗結合。間接免疫熒光需要使用二抗。室溫避光孵育1h.PBST漂洗3次,每次衝洗5min後,再用蒸餾水漂洗一次。
(7) 封片及檢測。滴加封片劑一滴,封片,熒光顯微鏡檢查。
(一)細胞準備
用yong於yu免mian疫yi熒ying光guang實shi驗yan的de細xi胞bao可ke以yi是shi直zhi接jie生sheng長chang在zai蓋gai玻bo片pian上shang的de貼tie壁bi細xi胞bao,也ye可ke以yi是shi經jing過guo離li心xin後hou塗tu片pian的de懸xuan浮fu細xi胞bao或huo者zhe是shi將jiang取qu自zi體ti內nei的de組zu織zhi細xi胞bao懸xuan液ye離li心xin後hou塗tu片pian。貼tie壁bi良liang好hao的de細xi胞bao一yi般ban在zai培pei養yang時shi直zhi接jie放fang入rucoverslipsrangxibaoshengchangzaiqishangjike,jinliangbimianshiyongtiebixingnengbuhaodexibaojinxingmianyiyingguangshiyan,yimianhouxudepiaoxicaozuoyinqixibaotuoluo。shaoshushiyanxuyaoshiyongzheleixibaohuozhexuanfuxibaojinxingmianyiyingguangguancha,jianyishiyongxibaolixinshuaipianjizhibeixibaopianhuozhijiezhibeixibaotupian。
(二)固定和通透
除研究細胞表麵抗原或不穩定抗原可不固定外,一般均應固定。固定的目的有三:
①防止細胞從玻片上脫落;
②除去防礙抗原-抗體結合的類脂;
③使標本易於保存。
標本的固定原則是:
①不能損傷細胞內的抗原;
②不能凝集蛋白質;
③應保持細胞和亞細胞結構;
④固定後應保持通透性,以保證抗體自由進入所有細胞與亞細胞組分與抗原結合。
常用的固定劑有多種,應根據所研究抗原的性質和所使用的抗體特性選擇適當的固定劑。通常固定方法可以分為兩類:有you機ji溶rong劑ji和he交jiao聯lian劑ji。有you機ji溶rong劑ji如ru甲jia醇chun和he丙bing酮tong等deng可ke去qu除chu類lei脂zhi並bing使shi細xi胞bao脫tuo水shui,同tong時shi將jiang細xi胞bao結jie構gou蛋dan白bai沉chen澱dian。交jiao聯lian劑ji如ru多duo聚ju甲jia醛quan通tong常chang通tong過guo自zi由you氨an基ji酸suan基ji團tuan形xing成cheng分fen子zi間jian橋qiao連lian,從cong而er產chan生sheng一yi種zhong抗kang原yuan相xiang互hu連lian接jie的de網wang絡luo結jie構gou。交jiao聯lian劑ji比bi有you機ji溶rong劑ji更geng易yi於yu保bao持chi細xi胞bao的de結jie構gou,但dan因yin為wei交jiao聯lian阻zu礙ai抗kang體ti結jie合he,可ke能neng會hui降jiang低di一yi些xie細xi胞bao組zu分fen的de抗kang原yuan性xing,因yin此ci需xu要yao增zeng加jia一yi個ge通tong透tou步bu驟zhou以yi使shi抗kang體ti能neng夠gou進jin入ru標biao本ben。兩liang種zhong固gu定ding方fang法fa都dou可ke能neng使shi蛋dan白bai抗kang原yuan變bian性xing,因yin此ci使shi用yong變bian性xing蛋dan白bai作zuo為wei抗kang原yuan生sheng產chan的de抗kang體ti在zai免mian疫yi熒ying光guang中zhong可ke能neng更geng為wei有you效xiao。
最常用的固定劑有多聚甲醛和甲醇,少數情況也使用乙醇,丙酮及戊二醛等進行固定。通常,細胞結構抗原、病毒及一些酶類抗原使用丙酮、乙yi醇chun及ji高gao濃nong度du的de甲jia醛quan固gu定ding可ke獲huo得de較jiao好hao的de結jie果guo,而er細xi胞bao膜mo相xiang關guan組zu分fen抗kang原yuan一yi般ban以yi多duo聚ju甲jia醛quan固gu定ding。細xi胞bao器qi和he細xi胞bao顆ke粒li內nei的de抗kang原yuan一yi般ban也ye用yong多duo聚ju甲jia醛quan固gu定ding,並bing需xu要yao進jin行xing通tong透tou以yi使shi抗kang體ti能neng達da到dao抗kang原yuan表biao位wei。
通(tong)透(tou)步(bu)驟(zhou)隻(zhi)在(zai)檢(jian)測(ce)細(xi)胞(bao)內(nei)抗(kang)原(yuan)表(biao)位(wei)的(de)時(shi)候(hou)才(cai)需(xu)要(yao),因(yin)為(wei)抗(kang)體(ti)需(xu)要(yao)進(jin)入(ru)細(xi)胞(bao)內(nei)部(bu)去(qu)檢(jian)測(ce)蛋(dan)白(bai)。但(dan)是(shi),如(ru)果(guo)待(dai)檢(jian)測(ce)的(de)是(shi)跨(kua)膜(mo)蛋(dan)白(bai),且(qie)其(qi)抗(kang)原(yuan)表(biao)位(wei)處(chu)於(yu)胞(bao)質(zhi)內(nei)區(qu)域(yu),則(ze)同(tong)樣(yang)需(xu)要(yao)對(dui)細(xi)胞(bao)進(jin)行(xing)通(tong)透(tou)。相(xiang)反(fan),如(ru)果(guo)所(suo)檢(jian)測(ce)的(de)抗(kang)原(yuan)表(biao)位(wei)位(wei)於(yu)膜(mo)蛋(dan)白(bai)的(de)胞(bao)外(wai)段(duan),則(ze)不(bu)需(xu)要(yao)進(jin)行(xing)通(tong)透(tou)。丙(bing)酮(tong)本(ben)身(shen)具(ju)有(you)通(tong)透(tou)作(zuo)用(yong),因(yin)此(ci)用(yong)丙(bing)酮(tong)作(zuo)為(wei)固(gu)定(ding)劑(ji)時(shi)是(shi)不(bu)需(xu)要(yao)通(tong)透(tou)的(de)。甲(jia)醇(chun)同(tong)樣(yang)具(ju)有(you)通(tong)透(tou)作(zuo)用(yong),但(dan)有(you)些(xie)場(chang)合(he)並(bing)不(bu)適(shi)合(he)用(yong)甲(jia)醇(chun),因(yin)為(wei)一(yi)些(xie)表(biao)位(wei)對(dui)甲(jia)醇(chun)非(fei)常(chang)敏(min)感(gan)。常(chang)用(yong)的(de)通(tong)透(tou)劑(ji)是(shi)去(qu)垢(gou)劑(ji),如(ru)Triton ,NP-40,以及Tween 20, Saponin, Digitonin 和 Leucoperm等。Triton和NP-40屬(shu)於(yu)烈(lie)性(xing)去(qu)垢(gou)劑(ji),可(ke)部(bu)分(fen)溶(rong)解(jie)細(xi)胞(bao)核(he)膜(mo),因(yin)此(ci)非(fei)常(chang)適(shi)合(he)核(he)抗(kang)原(yuan)檢(jian)測(ce)。但(dan)應(ying)該(gai)注(zhu)意(yi)的(de)是(shi),如(ru)果(guo)在(zai)高(gao)濃(nong)度(du)下(xia)使(shi)用(yong)或(huo)者(zhe)作(zuo)用(yong)時(shi)間(jian)過(guo)長(chang),它(ta)們(men)將(jiang)破(po)壞(huai)蛋(dan)白(bai),從(cong)而(er)影(ying)響(xiang)實(shi)驗(yan)結(jie)果(guo)。Triton X-100是shi最zui常chang用yong的de通tong透tou劑ji,但dan是shi它ta將jiang破po壞huai細xi胞bao膜mo,因yin此ci不bu適shi用yong於yu細xi胞bao膜mo相xiang關guan抗kang原yuan。後hou麵mian一yi組zu去qu垢gou劑ji要yao溫wen和he得de多duo,它ta們men可ke以yi在zai細xi胞bao質zhi膜mo上shang形xing成cheng足zu夠gou大da的de孔kong隙xi以yi允yun許xu抗kang體ti通tong過guo,但dan是shi不bu會hui溶rong解jie細xi胞bao質zhi膜mo。適shi於yu胞bao質zhi抗kang原yuan或huo者zhe質zhi膜mo上shang靠kao近jin胞bao質zhi一yi麵mian的de抗kang原yuan,也ye適shi於yu可ke溶rong性xing的de核he抗kang原yuan。
一yi般ban的de操cao作zuo程cheng序xu是shi先xian固gu定ding後hou通tong透tou,但dan針zhen對dui有you些xie水shui不bu溶rong性xing的de目mu的de抗kang原yuan的de檢jian測ce宜yi先xian通tong透tou再zai固gu定ding,這zhe樣yang做zuo的de原yuan因yin主zhu要yao是shi可ke以yi通tong過guo通tong透tou去qu除chu許xu多duo水shui溶rong性xing的de蛋dan白bai,從cong而er大da大da減jian少shao了le免mian疫yi熒ying光guang的de背bei景jing和he非fei特te異yi性xing信xin號hao。固gu定ding後hou以yi冷lengPBS液漂洗,最後以蒸餾水衝洗,防止自發性熒光。
(三)封閉
封閉的目的是為了減少抗體的非特異性結合,最常用的封閉劑為1% BSA, PBS pH 7.5,其他可選擇的封閉劑還有 1% gelatin, 1%bovine 或與二抗種屬相同的血清(3-10%)等。
(四)抗體孵育
zhijiemianyiyingguangfazhongdeyikanghejianjiemianyiyingguangfazhongdeerkangdoushiyingguangkangti,yincizaizhexiekangtifuyudeshihoubixuzhuyibiguang。ciwai,weibaozhengjiehezhilianghefangzhiganzao,kangtifuyuyingjinliangzaishihezhongjinxing。
(五)封片及熒光觀察
標(biao)記(ji)好(hao)熒(ying)光(guang)的(de)細(xi)胞(bao)片(pian)原(yuan)則(ze)上(shang)可(ke)以(yi)直(zhi)接(jie)進(jin)行(xing)觀(guan)察(cha),特(te)別(bie)是(shi)有(you)時(shi)候(hou)封(feng)片(pian)不(bu)當(dang)反(fan)而(er)使(shi)得(de)前(qian)功(gong)盡(jin)棄(qi)。但(dan)在(zai)絕(jue)大(da)多(duo)數(shu)情(qing)況(kuang)下(xia),為(wei)了(le)保(bao)存(cun)結(jie)果(guo),以(yi)便(bian)進(jin)一(yi)步(bu)觀(guan)察(cha)、照像、tongjifenxideng,xuzuofengpianchuli。changguidefangfashicaiyongganyouhuozhongxingshuzhifengpian,weilezengqiangfengpiandexiaoguo,wangwangxuyaozaifengpianshitianjiateshudekangyingguangcuimieji。
(六)標本保存
由you於yu熒ying光guang色se素su和he蛋dan白bai質zhi分fen子zi的de穩wen定ding性xing都dou是shi相xiang對dui的de,因yin此ci隨sui著zhe保bao存cun時shi間jian的de延yan長chang,在zai各ge種zhong條tiao件jian影ying響xiang下xia,標biao記ji蛋dan白bai可ke能neng變bian性xing解jie離li,失shi去qu其qi應ying有you的de亮liang度du和he特te異yi性xing。因yin此ci給gei標biao本ben的de 保存帶來一定的困難,所以在標本進行熒光染色之後應立即觀察。由於性能良好的抗熒光淬滅劑的出現,熒光標記的標本可以在低溫(4℃或-20℃)下(xia)保(bao)存(cun)相(xiang)當(dang)長(chang)的(de)時(shi)間(jian)。在(zai)某(mou)些(xie)情(qing)形(xing)下(xia),考(kao)慮(lv)到(dao)實(shi)驗(yan)的(de)成(cheng)本(ben)及(ji)實(shi)驗(yan)條(tiao)件(jian),也(ye)可(ke)以(yi)采(cai)取(qu)權(quan)宜(yi)的(de)辦(ban)法(fa),比(bi)如(ru)固(gu)定(ding)標(biao)本(ben)片(pian)後(hou)低(di)溫(wen)保(bao)存(cun),在(zai)需(xu)要(yao)時(shi)再(zai)進(jin)行(xing)熒(ying)光(guang)標(biao)記(ji),即(ji)隨(sui)用(yong)隨(sui)染(ran)。
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