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1、Heatshockproteins(HSPs)areagroupofproteinsthatarepresentinallcellsinalllifeforms.Theyareinducedwhenacellundergoesvarioustypesofenvironmentalstresseslikeheat,coldandoxygendeprivation.Heatshockproteinsarealsopresentincellsunderperfectlynormalconditions.Theyactlike“chaperones”,makin
2、gsurethatthecell’sproteinsareintherightshapeandintherightplaceattherighttime.Forexample,HSPshelpnewordistortedproteinsfoldintoshape,whichisessentialfortheirfunction.Theyalsoshuttleproteinsfromonecompartmenttoanotherinsidethecell,andtransportoldproteinsto“garbagedisposals”insideth
3、ecell.Heatshockproteinsarealsobelievedtoplayaroleinthepresentationofpiecesofproteins(orpeptides)onthecellsurfacetohelptheimmunesystemrecognizediseasedcells.Fordecadesithasbeenknownthatanimalscanbe‘vaccinated’againstcancer.Thisishowitworks:Tumorcellscanbeweakenedandinjectedlikeava
4、ccineintoamouse.Afterwards,ifthesesametumorcells,atfullstrength,areinjectedintothemouse,themousewillrejectthetumorcellsandcancerwillnotdevelop.However,ifamousehasnotbeenvaccinatedinthismanner,thetumorcellswill“takeroot”andthemousewilldevelopcancer.Althoughitwasclearthatanimalscou
5、ldbevaccinatedagainstcancer,foralongtimeitwasnotknownhowitworked.Thenabout25yearsago,agraduatestudentnamedPramodSrivastavabeganaseriesofexperiments.Hetooktumorcells,brokethemopen,andseparatedthedifferentpartsofthecellsintofractions.Hethenusedeachofthefractionsas“vaccines”toseewhi
6、chfractionprotectedthemicefromdevelopingcancer.Aftermanyexperiments,hefoundthattheelementresponsibleforprotectingthemicewasheatshockproteins.热应急蛋白是一组存在于一切生命形式的所有细胞中的蛋白质。细胞处于不同形式的环境压力(如遇热、遇冷或缺氧)下就会诱发这种蛋白质的产生。在完全正常的条件下,细胞内也会产生热应急蛋白,这些蛋白质就像“陪护”一样,确保细胞内的蛋白质在合适的时间处于合适的位置并具有合适的形状。例如,它们
7、帮助新生细胞或变形的细胞折叠成形,这对于细胞功能的发挥极其重要。热应急蛋白还将蛋白质从细胞的一个部分转移到另一个部分,或将衰老的蛋白质送入细胞的“垃圾处理厂”。科学家认为它们对于细胞表面蛋白质或多肽的生成也起着作用,从而帮助免疫系统辨认不健康的细胞。几十年前人们就已经了解到动物可以通过“接种疫苗”抗癌,其原理是:肿瘤细胞可以被弱化并像疫苗一样注射到小鼠体内。此后,如果将相同的、已充分发育的肿瘤细胞注入小鼠,小鼠就会对这些肿瘤细胞产生排斥,因此不会患上癌症。然而,如果小鼠没有以上述方式接受免疫,肿瘤细胞就会“生根'导致小鼠患上癌症。虽然人们已经清楚地了解到
8、动物可以通过免疫抗癌,但在很长一段时间内对于该过程的原理并不了解。大约25年前,