t-cell mediated immunity
TRANSCRIPT
T Cell-Mediated Immunity
Dr Alok TripathiDepartment of [email protected]
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EffectorT CellPathogenLocationAntigenPresentationTarget CellActionCellularImmunityTc CD8cytotoxicCytoplasmInfected cell MHC IInfected cellapoptosis Th1 CD4inflammatory MacrophagevesiclesMacrophage MHC IIMacrophage activation to kill pathogenHumoralImmunityTh2 CD4helperExtracellularAPC MHC IIB cell antibody production
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Ig SuperfamilyAdhesion MoleculeTissue DistributionIntegrin LegendCD2 (LFA-2)T cellsLFA-3 on APCICAM-1 (CD 54)Activated endotheliumdendritic cellsT cellsLFA-1 on T cellsMAC-1 on macrophagesICAM-2 (CD102)Resting endotheliumLFA-1 on T cellsICAM-3 (CD50)Nave T cellsDC-SIGN on dendritic cellsLFA-3 (CD58)LymphocytesAPCCD2 on T cells
CD40P
mIgM & mIgD
APC TCRs
Ag MHC-IICD40L IL2,IL4, IL10, IL5, & IFN B7 & CD28
T Cell ActivationKillEndogenous AntigenActivate CTL KillInfected CellExogenous AntigenActivate ThStimulateM
Endosomal Pathogens
Nave T Cell MHC-I~PeptideCD-8T CellMHC-IICD-4T Cell Co-Stimulatory Signals
APCOnly professional APC (DC, NK & B- Cells ) have both MHC-I;II and can deliver co-stimulatory signal
Proliferate & Differentiate
Perform their function when they encounter Target cell-MHC~peptide
APC [B-Cell] ThY
AgYY
MHC-IIPB7CD-28TCRCD-40CD-40L CK CO-STIMULATORY SIGNALS
Nucleus
Singling CascadesProcessing & Presentation of Ag
T cells Anergy
APC=DC,M or B cells:DC deliver both signal and are the best APC and are the responsible for the activation of the most of the nave cells
CD-40LT-CellsAg & Co-Stimulatory SignalsActivated T CellsExpress
Other receptors
Enhance Co stimulation
APC
CD-40To provide more co stimulation Activate M &B- CellsFurther Interaction of APC & T Cells
The immune response therefore depends upon PUSH of the antigen stimulation to activate T cells in to effectors cells and PULL of negative signal that curtail T cells responseB7CTAL-4ICOS 4-IBB/CD-137
4-1BBLTo further activate T & APCLICOSInducible co stimulator