SlideServe
Télécharger Obtenir Pro
Menu
Accueil Pro
Préférences
ApparenceLight Aide et commentaires
© SlideServe · v2026

DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS

raffaello-payton avatar
raffaello-payton
18 diapositives · 406 Views · Nov 10, 2014

DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS. The cellular organization of the thymus. The proportion of the thymus that produces T cells decreases with age. Commitment to the T-cell lineage changes receptor expression. Lack of IL7 signaling (IL7 or IL7R) stalls

#differentiation and maturation of t cells in the thymus #differentiation and maturation of t cells in the thymus ppt #powerpoint #presentation
DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS - slide 1
01 / 18DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS
1 / 17

Télécharger la présentation

DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation

Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement. Téléchargez la présentation en cliquant sur ce lien. Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.

F I N

Plus de contenu associé

Transcription de la présentation

  1. DIFFERENTIATION AND MATURATION OF T CELLS IN THE THYMUS

  2. The cellularorganization of thethymus

  3. The proportion of the thymus that produces T cells decreases with age.

  4. Commitment to theT-celllineagechanges receptor expression Lack of IL7 signaling (IL7 or IL7R) stalls EarlyT-celldevelopment SCIDs

  5. T-cell development is driven by the receptor Notch 1.

  6. a a REGULATED T-CELL DIFFERENTIATION APC CD4+CD8+ TCR preT- Epithelial cell immatureTcell pre Tcell ANTIGEN RECOGNIZING RECEPTOR pro T cell SIGNALING RECEPTOR NO ANTIGEN RECOGNIZING RECEPTOR

  7. α:β and γ:δ T cellsdevelopfrom a commondouble-negativeT-cellprogenitor. Only a few percent of the developing thymocytes lives, the rest areeliminated by apoptosis

  8. T-cell receptor gene rearrangements in double-negative thymocytes can lead to the expression of either a γ:δ receptor or a pre-T-cell receptor.

  9. Geneexpressionthroughthe stagesof α:β T-cell development in developing T cells.

  10. NemazeeNature Reviews Immunology6, 728–740 (October 2006) | doi:10.1038/nri1939

  11. POSITIVE SELECTION OF DOUBLE POSITIVE (DP) T CELLS ALSO DIRECTS CD4 AND CD8 SINGLE POSITIVE (SP) T CELL COMMITMENT POSITIVE SELECTION FOR 3 – 4 DAYS, SUCCESSIVE α-GENE REARRANGEMENTS BARE LYMPHOCYTE SYNDROME (BLS) Lack of MHC class I – no CD8+ cellsLack of MHC class II – no CD4+ cells

  12. SELECTION OF T LYMPHOCYTES IN THE THYMUS AICD – Activation Induced Apoptosis PERIPHERAL TOLERANCE UNDER THE CAPSULE • The primary T cell pool is biased to MHC-specificity (V genes) 1-2% for one allotype • Focusing the T cell pool to self MHC recognition (+) • Elimination of useless and self agressive clones (-) • CENTRAL TOLERANCE • Focusing the T cell repertoire for recognition of non self • CD4+ and CD8+ T cell use the same TCR repertoire • Individualized T cell repertoire available in the periphery • CD4 and CD8 co-stimulatory molecules are involved in positive selection IL-7-dependent proliferation CORTEX CD4-CD8- DN β+preTα TCRαβ CD4+CD8+ DP TCR(-) sMHC+sPsMHC+fPfMHC+fP selection CORTEX/ MEDULLA   NO  – selection MEDULLA – AICD αβTCR αβTCR CD4+CD8+

  13. SELECTION OF THE T CELL REPERTOIRE – CENTRAL TOLERANCE POSITIVE SELECTION – Thymiceducation (no instructionforspecificity) Lowavidityinteraction of MHC - selfpeptide - TCR Thymicepithelialcells Selfpeptidecomposition and concentration (foreignpeptidesarenotpresent) Lowpeptidedoseinducespositiveselection – specialligands 80-90% of DN (CD4-CD8-) T cells is NOT positivelyselected PASSIVE CELL DEATH BY NEGLECT NEGATIVE SELECTION – Centralselftolerance Highavidity of MHC - selfpeptide - TCR interaction Ubiquitous and abundantselfantigensarepresentinthethymus Highpeptidedoseinducesnegativeselection Anythymicantigenpresentingcell: epithelialcells, bonemarrow-derived macrophages, dendriticcells THE GENERATION OF SELF MHC + FOREIGN PEPTIDE SPECIFIC T CELLS REQUIRES WEAK INTERACTION WITH SELF MHC + SELF PEPTIDE SELF RESTRICTED AND TOLERANT PERIPHERAL T CELL REPERTOIRE PHYSIOLOGICAL TRESHOLD NOT COMPLETE

  14. γδT-cells • MHC-independent, CD1c and CD1d dependent • Doublemegative • comprise up to 50% of the intra-epithelial lymphocyte population • expandedinintracellularbacterialinfections(Mycobacteriumtuberculosis and Listeriamonocytogenes), extracellularinfections (Borreliaburgdorferi) • a population that is expanded in certain disease states such as celiac disease