Book 2Unit 7Text BWord文档格式.docx
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Book 2Unit 7Text BWord文档格式.docx
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4Afewyearslater,PeterMedawarandhisteamattheUniversityofBirmingham,U.K.,showedthatfraternaltwincattlewithmixedchimerismreadilyacceptskingraftsfromeachother.MedawardidnotimmediatelyappreciatethelinktoOwen'
swork,butwhenhesawtheconnection,hedecidedtoinjectfetalmiceinuterowithtissuefrommiceofadifferentstrain.InapublicationinNaturein1953,theresearchersshowedthat,afterbirth,someofthesemicetoleratedskingraftsfromdifferentstrains.Thisinfluentialexperimentledmanytodevotetheircareerstotransplantationandalsoraisedhopesthattheworkwouldleadtocuresforautoimmunediseases.
5Immunologists,manyofthemworkingwithmice,havesincespelledoutseveraldetailedmechanismsbehindtolerance.Theimmunesystemcan,forexample,dispatch“regulatory”cellsthatsuppressimmuneattacksagainstself.Orthesystemcanforceharmfulimmunecellstocommitsuicideortogointoadysfunctionalstuporcalledanergy.Researchersindeednowknowfinedetailsaboutthegenes,receptors,andcell-to-cellcommunicationsthatdrivetheseprocesses.
6Yetit’sonemattertounravelhowtheimmunesystemworksandanothertofigureoutsafewaystomanipulateit.Transplantresearchersarepursuingthreemainstrategiestoinducetolerance.OnebuildsonMedawar'
sexperimentsbytryingtoexploitchimerism.Researchersinfusethepatientwiththeorgandonor'
sbonemarrowinhopesthatthedonor’simmunecellswillteachthehosttotoleratethetransplant;
donorimmunecellsthatcomealongwiththetransplantedorganalso,somecontend,canteachtolerance.AsecondstrategyusesdrugstotrainTcellstobecomeanergicorcommitsuicidewhentheyseetheforeignantigensonthetransplantedtissue.ThethirdapproachturnsupproductionofTregulatorycells,whichpreventspecificimmunecellsfromcopyingthemselvesandcanalsosuppressrejectionbysecretingbiochemicalscalledcytokinesthatdirecttheimmuneorchestratochangeitstune.
7Allthesestrategiesfaceacommonproblem:
Itismaddeninglydifficulttojudgewhethertheapproachhasfailedorsucceededbecausetherearenoreliable“biomarkers”thatindicatewhetherapersonhasbecometoleranttoatransplant.Sotheonlywaytoassesstoleranceistostopdrugtreatment,whichputsthepatientatriskofrejectingtheorgan.Similarly,ethicalconcernsoftenrequireresearcherstotestdrugsaimedatinducingtoleranceinconcertwithimmunosuppressivetherapy.This,inturn,canunderminethedrugs'
effectivenessbecausetheyneedafullyfunctioningimmunesystemtodotheirjob.
8Ifresearcherscancompletetheir50-yearquesttoinduceimmunetolerancesafelyandselectively,theprospectsforhundredsofthousandsoftransplantrecipientswouldbegreatlyimproved,andso,too,mighttheprospectsforcontrollingautoimmunediseases.
Source:
Science1July2005:
Vol.309no.5731p.97
DOI:
10.1126/science.309.5731.97ByJonCohen
http:
//www.sciencemag.org/content/309/5731/97.full
(words:
760)
WordsandExpressions
recipient[rɪ'
sɪpɪənt]n.apersonwhogetssomething接受者
immunosuppressant[,ɪmjʊnəʊsə'
presənt]n.adrugthatlowersthebody'
snormalimmuneresponse[免疫][药]免疫抑制剂(素)
reject[rɪ'
dʒekt]vt.refusetoacceptoracknowledge拒绝;
排斥;
抵制;
在免疫上排斥
tinker['
tɪŋkə]vt.trytofixormend修补;
粗修
fraternal[frə'
tɜːnl]adj.derivedfromtwoova由两个受精卵发育而成的(孪生子);
异卵双生的[区别于identical]
fraternaltwin异卵双生
placenta[plə'
sentə]n.thevascularorganinmammalsexceptmonotremesandmarsupialsthatunitesthefetustothematernaluterusandmediatesitsmetabolicexchangesthroughamoreorlessintimateassociationofuterinemucosalwithchorionicandusuallyallantoictissues;
also:
ananalogousorganinanotheranimal[胚]胎盘;
[植]胎座
graft[grɑ:
ft]vi./vt.toimplant(livingtissue)surgically移植;
嫁接
n.移植;
嫁接
fetal['
fiːtl]adj.oforrelatingtoafetus【胚胎学】胎的;
(似)胎儿的[亦作foetal]
inutero[ɪn'
ju:
tərəʊ]intheuterus[拉丁语]在子宫内;
尚未出生,在出生前
strain[streɪn]n.agroupofpresumedcommonancestrywithclear-cutphysiologicalbutusuallynotmorphologicaldistinctions种;
族;
菌株
dysfunctional[dɪs'
fʌŋkʃənəl]adj.impairedorabnormalfunctioning(器官)功能紊乱的,机能不良(或失调)的,机能障碍的
stupor['
stjuːpə]n.thefeelingofdistressanddisbeliefthatyouhavewhensomethingbadhappensaccidentally昏迷,恍惚;
麻木
anergy['
æ
nəʤɪ]n.aconditioninwhichthebodyfailstoreacttoanantigen【免疫学】无免疫性;
抗原注射无反应性
anergic[æ
'
nɜ:
ʤɪk]adj.无免疫性的
biochemical[baɪəʊ'
kemɪkəl]adj.oforrelatingtobiochemistry;
involvingchemicalprocessesinlivingorganisms生物化学的
biochemicalreaction生物化学反应,生化反应
biochemicalengineering生化工程
biochemicalanalysis生化分析;
生物技术分析;
生物化学分析
biochemicaldegradation生物化学降解
cytokine['
saɪtə,kaɪn]n.anyofaclassofimmunoregulatoryproteins(asinterleukinorinterferon)thataresecretedbycellsespeciallyoftheimmunesystem[细胞]细胞因子;
细胞激素
biomarker[,baɪə'
mɑ:
kə]n.生物标志物;
生物标记;
生物指标
immunosuppressive[,ɪmjʊnəʊsə'
presɪv]adj.oforrelatingtoasubstancethatlowersthebody'
snormalimmuneresponseandinducesimmunosuppression免抑制疫力的;
抑制免疫力的
ComprehensionExercises
Exercise1Terminologyinterpretation
Directions:
Pleaseexplainthefollowingtermsbasedonyourunderstandingofthetext.
1)immunetolerance
2)mixedchimerism
3)functionsofTregulatorycells
4)biomarkers
Keys:
1)Immunetoleranceisasituationwhentransplantrecipientswhostoptakingimmunosuppressantshavenotrejectedtheirforeignorgans.
2)Mixedchemerismisastatewhenfraternaltwinsshareaplacentaandarebornwitheachother’sreadbloodcells.
3)ThefunctionofTregulatorycellsistopreventspecificimmunecellsfromcopyingthemselvesandsuppressrejectionbysecretingbiochemicalscalledcytokinesthatdirecttheimmuneorchestratochangeitstune.
4)Biomarkersarebiologicalmoleculesthatindicatewhetherapersonhasbecometoleranttoatransplantornot.
Exercise2Multiplechoices
Pleasechoosethemostsuitablechoicetoeachquestionsbelow.
1)Whatisthebiggestproblemtransplantrecipientsencounter?
A)Therearescarcesourcesofthetransplantorgans.
B)Thetransplanttechnologyisstillatexperimentallevel.
C)Theirimmunesystemrejectstheforeignorgans.
D)Theimmunosuppressantshaveserioussideeffects.
2)Whatistheobstaclethattransplantresearchersareconfrontedwith?
A)Toseekformethodstoinduceimmunetolerancetotransplants.
B)Howtotrainimmunesystemtorejectforeignorgans.
C)Tofindoutthetreatmentsforautoimmunedisease.
D)Todecidewhetherdrugstestedforimmunetoleranceareeffectiveornot.
3)Whatistheimplicationoftheword“marathon”inParagraph3?
A)Seekingmethodstoinduceimmunetoleranceisalongwaytogo.
B)Theresearchworkneedsthespiritofpersistency.
C)Thescientists’devotioncanguaranteethesuccessoftheresearchworks.
D)Alloftheabove.
4)Whichimmunemechanismisnotexplainedbytheimmunologists?
A)Thesafewaytoapplyimmunesystemtoinducetolerancetoforeignorgans.
B)Theimmunesystemcanforceharmfulimmunecellstocommitsuicide.
C)Cell-to-cellcommunicationscandrivetheharmfulimmunecellsintoanergicsituation.
D)Regulatorycellscanbesenttosuppressimmuneattacksagainstself.
5)Whatdosereliable“biomarker”refertoaccordingtothetext?
A)Tcellstrainedtotoleratethetransplant.
B)Anybiologicalmoleculesindicatingwhetherapersonhasbecometolerancetoatransplant.
C)Tregulatorycellsusedtoadaptforeignorganstoimmunesystem.
D)Cytokinespreventingspecificimmunecellsfromcopyingthemselves.
6)Whichofthefollowingstatementsisincorrectaccordingtothetext?
A)Researchershaveunderstoodtheprincipleofimmunetoleranceatthemolecularandcellul
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