Medical Microbiology

forTcellactivationtooccur,antigen-transportingAPCsmustfirstreachthe organizedsecondarylymphoidorgans(Fig.2. 12 ),sincepropercont ...

compartmentalizedorgans.ThecytokinesIFNc,IL-1,IL-2,IL-4,andIL-1 2 play animportantroleinthisprocess—asdovariousotherfactors. Dur ...

cells—oronlyrequiresthesecellsindirectly.However,shouldtheantigenstim- ulusandtheaccompanyinginflammationbeofalow-levelnature,th ...

Cytokines(Interleukins)andAdhesion................ Cytokinesarebioactivehormones,normallyglycoproteins,whichexercisea widevariet ...

tiationmoleculesandregulationofcellsurfacemoleculeexpression).The functionsofcytokinesareusuallypleiotropic,inthattheydisplayanu ...

ImmuneResponsesandEffectorMechanisms 79 AntiviralProtectionbyTCells Perforin T cell T cell Perforin Noncytopathic virus Cytopath ...

80 2 BasicPrinciplesofImmunology Table2. 6 TheMostImportantImmunologicalCytokinesandCostimulators plusTheirReceptorsandFunctions ...

ImmuneResponsesandEffectorMechanisms 81 Table2. 6 Continued:TheMostImportantImmunologicalCytokines... Cytokines/costimula- tors/ ...

82 2 BasicPrinciplesofImmunology Table2. 6 Continued:TheMostImportantImmunologicalCytokines... Cytokines/costimula- tors/chemoki ...

ImmuneResponsesandEffectorMechanisms 83 Table2. 6 Continued:TheMostImportantImmunologicalCytokines... Cytokines/costimula- tors/ ...

Celladhesionmoleculesoftenplayanessentialroleincell-to-cellinterac- tions.Twolympho-hematopoieticcellscanonlyestablishcontactifo ...

thecytomegalyvirus,encodeproteinsthatarefunctionallyanalogousto chemokinereceptors.Thisallowsarapidneutralizationoflocallyinduce ...

digestion.OpsonizationinvolvesthecoatingofsuchmicrobeswithFc-ex- pressingantibodieswhichfacilitatestheirphagocytosisbygranulocyt ...

&Solubilizationofotherwiseinsolubleantigen-antibodycomplexes. &Promotionofthetransportofimmunecomplexes,andtheireliminat ...

antibody-inducedcomplementactivationand“alternative”activationviaC3 (Fig.2. 16 ). Duringclassicactivationofcomplement,C1qmustbeb ...

andalternativeactivation,butisnotnecessarilyessentialsincethereleased chemotaxinsandopsoninsareoftenaloneenoughtomediatethefunct ...

SomecomponentsmediategeneralregulatoryfunctionsonB-cellresponses, especiallyviaCR1andCR2. ImmunologicalCellDeath................ ...

formoftoleranceinvolvesantigenrecognitionbyantigen-reactiveperipheralT cells,followedbyaprocessofclonalcellproliferation,enddiff ...

ipherywillcontinuouslybeinducedtoundergoactivationandexhaustion withinthesecondarylymphoidorgans. ExhaustiveT-cellinductionmostl ...

Insummary,thenon-responsivenessofT-cellscanbeachievedby:negative selectioninthethymus;byexcessiveinductionintheperiphery;orbyseq ...