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　　B細(xì)??(xi)胞??(bao)作??(zuo)為??(wei)“抗??(kang)體??(ti)工??(gong)廠??(chang)”?，能??(neng)針??(zhen)對(duì)??(dui)不??(bu)同??(tong)病??(bing)原?(yuan)體??(ti)定??(ding)制??(zhi)特??(te)異??(yi)性?(xing)抗?(kang)體??(ti)?，通??(tong)過??(guo)中??(zhong)和??(he)病??(bing)毒??(du)或??(huo)標(biāo)??(biao)記?(ji)病??(bing)原??(yuan)體??(ti)協(xié)??(xie)助??(zhu)清??(qing)除??(chu)機(jī)??(ji)制??(zhi)；同??(tong)時(shí)?(shi)分??(fen)化??(hua)出??(chu)的??(de)記??(ji)憶??(yi)B細(xì)??(xi)胞??(bao)可?(ke)在??(zai)免??(mian)疫??(yi)結(jié)??(jie)束??(shu)后??(hou)保??(bao)留??(liu)抗??(kang)體??(ti)“圖??(tu)譜??(pu)”?，實(shí)??(shi)現(xiàn)??(xian)快?(kuai)速??(su)二??(er)次??(ci)應(yīng)??(ying)答??(da)??。??　　第??(di)一??(yi)道??(dao)防??(fang)御??(yu)是??(shi)物??(wu)理??(li)屏?(ping)障??(zhang)??，比??(bi)如??(ru)皮??(pi)膚??(fu)和??(he)黏??(nian)膜??(mo)??，像??(xiang)城??(cheng)墻??(qiang)一??(yi)樣??(yang)覆??(fu)蓋??(gai)體?(ti)表??(biao)??，通??(tong)過??(guo)汗?(han)液??(ye)、皮??(pi)脂??(zhi)和??(he)黏??(nian)液??(ye)中??(zhong)的??(de)抗?(kang)菌??(jun)成??(cheng)分??(fen)??，直??(zhi)接??(jie)阻??(zu)擋??(dang)細(xì)??(xi)菌??(jun)、病??(bing)毒??(du)入??(ru)侵??(qin)；比??(bi)如??(ru)呼??(hu)吸??(xi)道??(dao)纖?(xian)毛??(mao)??，如??(ru)同??(tong)護(hù)??(hu)城?(cheng)河??(he)的??(de)“清??(qing)道??(dao)夫??(fu)”??，通??(tong)過??(guo)擺??(bai)動(dòng)??(dong)??，將??(jiang)灰??(hui)塵?(chen)和??(he)病??(bing)原??(yuan)體??(ti)排??(pai)出??(chu)體??(ti)外??(wai)??。??。