兽医专业英语(扬州大学)lessonth.ppt
LessonThirteenImmuneSystem
NewwordsandphrasesAnatomicReceptorNomenclaturePrecursorThymusNaiveProgenyQuiescentHumoralMononuclearPhagocyteDendriticFollicularHematopoieticResidenceArchitectureCytokinesLangerhanscellGastrointestinalTonsilRecruitMicrobialVascularendothelialcells
Theanatomicorganizationofthecellsandtissuesoftheimmunesystemisofcriticalimportanceforthegenerationofimmuneresponses.Thisorganizationpermitsthesmallnumberoflymphocytesspecificforanyoneantigentolocateandrespondeffectivelytothatantigenregardlessofwhereinthebodytheantigenisintroduced.Text
Theadaptiveimmuneresponsedependsonantigen-specificlymphocytes,accessorycellsrequiredforlymphocyteactivation,andeffectorcellsthateliminateantigens.BandTlymphocytesexpresshighlydiverseandspecificantigenreceptorsandarethecellsresponsibleforthespecificityandmemoryofadaptiveimmuneresponses.12
Naturalkiller(NK)cellsareadistinctclassoflymphocytesthatdonotexpresshighlydiverseantigenreceptorsandwhosefunctionsarelargelyininnateimmunity.Manysurfacemoleculesaredifferentiallyexpressedondifferentsubsetsoflymphocytes,aswellasonotherleukocytes,andthesearenamedaccordingtotheCDnomenclature.
BothBandTlymphocytesarisefromacommonprecursorinthebonemarrow.Bcelldevelopmentproceedsinthebonemarrow,whereasTcellprecursorsmigratetoandmatureinthethymus.Aftermaturing,BandTcellsleavethebonemarrowandthymus,enterthecirculation,andpopulateperipherallymphoidorgans.
Na?veBandTcellsarematurelymphocytesthathavenotbeenstimulatedbyantigentobecomedifferentiatedlymphocytes.Whentheyencounterantigen,theydifferentiateintoeffectorlymphocytesthathavefunctionsinprotectiveimmuneresponses.EffectorBlymphocytesareantibody-secretingplasmacells.EffectorTcellsincludecytokine-secretingCD4+helperTcellsandCD8+cy