免疫系统紊乱immunedisorders+aids埃文斯维尔大学(美国).ppt

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1、ImmuneSystemDisordersImmuneSystemDisordersHypersensitivity(Allergy):Anabnormalresponsetoantigens.FourTypesofHypersensitivityReactions:TypeI(Anaphylactic)ReactionsTypeII(Cytotoxic)ReactionsTypeIII(ImmuneComplex)ReactionsTypeIV(Cell-Mediated)ReactionsTypeI(Anaphylactic)ReactionsOccurwithinmin

2、utesofexposuretoantigenAntigenscombinewithIgEantibodiesIgEbindstomastcellsandbasophils,causingthemtoundergodegranulationandreleaseseveralmediators:Histamine:Dilatesandincreasespermeabilityofbloodvessels(swellingandredness),increasesmucussecretion(runnynose),smoothmusclecontraction(bronchi).

3、Prostaglandins:Contractionofsmoothmuscleofrespiratorysystemandincreasedmucussecretion.Leukotrienes:Bronchialspasms.Anaphylacticshock:Massivedropinbloodpressure.Canbefatalinminutes.MastCellsandtheAllergicResponseMastCellsandtheAllergicResponseTypeII(Cytotoxic)ReactionsInvolveactivationofcomp

4、lementbyIgGorIgMbindingtoanantigeniccell.Antigeniccellislysed.Transfusionreactions:ABOBloodgroupsystem:TypeOisuniversaldonor.Incompatibledonorcellsarelysedastheyenterbloodstream.RhBloodGroupSystem:85%ofpopulationisRhpositive.ThosewhoareRhnegativecanbesensitizedtodestroyRhpositivebloodcells.

5、Hemolyticdiseaseofnewborn:Fetalcellsaredestroyedbymaternalanti-Rhantibodiesthatcrosstheplacenta.TypeIII(ImmuneComplex)ReactionsInvolvereactionsagainstsolubleantigenscirculatinginserum.UsuallyinvolveIgAantibodies.Antibody-Antigenimmunecomplexesaredepositedinorgans,activatecomplement,andcause

6、inflammatorydamage.Glomerulonephritis:Inflammatorykidneydamage.Occurswithslightlyhighantigen-antibodyratioispresent.ImmuneComplexMediatedHypersensitivityTypeIV(Cell-Mediated)ReactionsInvolvereactionsbyTDmemorycells.Firstcontactsensitizesperson.Subsequentcontactselicitareaction.Reactionsared

7、elayedbyoneormoredays(delayedtypehypersensitivity).DelayisduetomigrationofmacrophagesandTcellstositeofforeignantigens.Reactionsarefrequentlydisplayedontheskin:itching,redness,swelling,pain.TuberculosisskintestPoisonivyMetalsLatexinglovesandcondoms(3%ofhe