博士生課程3(1)-抗原

抗原(Antigen，Ag)

Conceptions

ImmunogenicityandSpecificityofAntigen

ClassificationofAntigen

Superantigen

andAdjuvant1.Antigen(Ag)︱BCR—TCRA.DefinitionofAg

---抗原是能與B

、

T淋巴細胞抗原識別受體結(jié)合,啟動免疫應答,并能與應答產(chǎn)物(抗體或效應T細胞)發(fā)生特異性結(jié)合的物質(zhì)B.2importantpropertiesofAg

immunogenicity

antigenicityBTcombinespecificallypathogen→Bcell→correspondingantibodyAg(Ab)

B.2importantpropertiesofAg

Immunogenicity

antigen↓IS↓induceIR↓productsofIR(Ab/effectorTcells)Combinespecifically→immunogenicity免疫原性是指能夠刺激機體產(chǎn)生特異性免疫應答，包括誘導產(chǎn)生抗體及效應性T淋巴細胞的能力

Antigenicity/immunoreactivity

---theabilityforinducinganIR,includinginduceproductionofantibodyandeffectorTcell

---theabilitytocombinespecificallywiththeAboreffectorTcellinducedbyitsown---能與其誘生的抗體或效應性T細胞發(fā)生特異性結(jié)合的能力,稱為抗原性或免疫反應性→antigenicity2.Completeantigen&haptenA.Completeantigen(完全抗原)---Substancesthathavebothimmuno-genicityandimmunoreactivity(antigenicity)B.Hapten

(半抗原)---Substancesthathaveimmunoreactivity

,but

lackofimmunogenicity?

hapten+carrier=completeantigen半抗原(無免疫原性)?

Haptencouple(偶聯(lián))toproteinorothercarriers(載體)toformcompleteantigen(有免疫原性)(二硝基苯)combinewith(有免疫反應性)combinewithcombinewithanti-dinitrobezene

(抗二硝基苯)3.Tolerogen&allergenantigen

→→T/B→→response

Tolerogenantigen→→T/B→→highresponse

Allergen

“hypersensitivity/allergy”

(超敏反應/變態(tài)反應)negative

“immunetolerance”

(免疫耐受)(stateofspecificnonresponse)Ⅱ.Immunogenicity

andSpecificityofantigen1.DecisivefactorsforimmunogenicityA.Foreigness(異物性)

Non-selfsubstances

SelftissueB.Physicochemicalcharacteristics在胚胎期未與免疫活性細胞充分接觸過的物質(zhì)均為異物?variousmicrobes?allogenicsubstance?heterogenicprotein(suchasimmunesera)

(including:changedorcryptical)Glutin(明膠)Glutin

+2%tyrosine→→

(酪氨酸)

免疫原性弱

免疫原性增強B.PhysicochemicalcharacteristicsMW>10kD

Moleculeweight

Complexityofstructure

Molecularconformationandaccessibility（分子構(gòu)象和易接近性）

YY

GlutanImmunogenicity+++

±+++分子構(gòu)象和易接近性不同,其免疫原性也不同Tyrosinepoly-lysinepoly-alanineC.Host

D.Immunizedroute

Geneticcharacteristicsofthehost

Age,sex,andstateofhealthA.Antigenicdeterminant(AD)2.Specificityofantigen抗原分子中決定抗原特異性的特殊化學基團稱為抗原決定基,又稱為表位(epitope);是與TCR/BCR及抗體特異性結(jié)合的基本單位抗間位氨基苯磺酸抗體(半抗原)

ThechemicalcompositionandspatialstructureofADdecidespecificityofAg

苯磺酸基苯砷酸基甲酸基---Thenumbersofepitopewhichcanbindtoantibody

Antigenicvalence*Naturalantigenispolyvalentantigen

能與抗體結(jié)合的抗原決定基(表位)的數(shù)目,稱為抗原的結(jié)合價多價抗原多價抗原specificityofimmunogenicityspecificityofimmunoreactivityinducebindingtoADADB.

ClassificationofAD

AccordingtostructureofAD?functionaldeterminant?crypticaldeterminant

AccordingtolocationofADonAgmolecule?lineardeterminant?

conformationaldeterminantAccordingtoADrecognizedby

TorBcell?Tcellepitope?BcellepitopeHaptenepitopeandcarrierepitope(i.e.BcellepitopeandTcellepitope)

?Tcellepitope---epitoperecognizedbyTCR?

Bcellepitope---epitoperecognizedbyBCR/Ab

T細胞只識別經(jīng)加工處理的線性表位，一般不識別構(gòu)象決定基*lineardeterminant*locationintheinside

ofantigen*conformationaldeterminantorlineardeterminant*locationonthesurface

of

naturalantigen

B細胞可識別線性表位或構(gòu)象決定基，且無需加工處理

321,2:B細胞表位3:T細胞表位31交叉反應Ag1Ag2

C.Commonantigenandcross-reaction

兩種不同抗原具有相同或相似的抗原決定簇,則稱為共同抗原(commonantigen)

抗體對具有相同或相似的抗原決定簇的不同抗原的反應,稱為交叉反應(共同抗原又稱交叉反應抗原)

Cross-reaction

Commonantigen溶血性鏈球菌腎小球基底膜大腸桿菌O14型腸粘膜共同抗原

急性腎小球腎炎共同抗原

潰瘍性結(jié)腸炎Ⅲ.Classificationofantigen1.DependonwhetherneedtheThcellforproducingtheantibodyA.Thymusdependentantigen(TD-Ag)B.Thymusindependent