1. Chapter 8 T Cell-Mediated Immunity

3. Activation of naïve T cells on encounter with antigen

13. Dendritic Cells Processing and Presentation

19. Naïve T cells encounter antigen during recirculation through lymphoid organs

20. Recirculating Naïve T-cells

24. Leukocyte adhesion molecules

27. Naïve T and B lymphocytes circulate in the blood and enter lymph nodes by crossing high endothelial venules

29. Cell-surface molecules of the immunoglobulin superfamily initiate lymphocyte adhesion to APC

31. Transient adhesive interactions between T cells & dendritic cells are stabilized by specific Ag recognition

37. Three types of professional APCs populate different parts of the lymph node Dendritic cells (or interdigitating cells) are situated in the cortical T-cell areas of the lymph node. Dendritic cells are the most effective antigen-presenting cell.

39. Three types of professional APCs populate different parts of the lymph node These distributions reflect differences in the functions and importance of the three types of professional antigen-presenting cells. B cells mainly populate the lymphoid follicles in the cortex.

43. Immature DC: DEC205 facilitates phagocytosis and pinocytosis of antigens. Mature DC: Increase expression of B7 co-stimulators, MHC molecules and adhesions molecules like DC-SIGN

49. Clustering of the TCR and a co-receptor initiates signaling within the T cell

50. Signaling pathways initiated by the T-cell receptor complex, its CD4 co-receptor and CD28

63. Cytokines produced by TH1 cells can suppress the differentiation of TH2 cells and Cytokines produced by TH2 cells can suppress the differentiation of TH1 cells.

66. T Cell-Mediated Immunity

68. The properties and functions of effector T- cells

69. After differentiating (secondary lymphoid organs) effector T cells detach from the APC that nursed their differentiation Effector T cells CD4 TH2 CD4 TH1 Cytotoxic CD8 T cells Sites of infection -CD8 kills infected cells -CD4 secrete cytokines Stays in the secondary lymphoid organs -CD4 secrete cytokines

72. Example of CD4 T cell Surface Molecules

82. Integrin VLA-4 enables effector T cells to home to inflamed tissue Recruitment of effectors T cells into inflamed or infected tissues T cell migration or antigen presentation

86. Many cytokine receptors signal through a pathway in which receptor-associated kinases activate transcript factors directly

88. TH1 &TH2 cells make characteristic sets of cytokines that have distinct effects on the immune response

91. Delivery of cytotoxins by CD8 T cells is aimed directly at the target cell. LG= lytic granules (red) MTOC= microtubule organizing center (microtubules – green) GA = golgi apparatus Initial contact has no effect Cytoskeleton reorganizes TCR:MHC Die

95. Apoptotic cell in early stages showing chromatin condensation (red) but well-defined plasma membrane that is shedding vesicles . Apoptotic cell in late stages has very condensed nucleus , no mitochondria , and the cytoplasm and cell membranes are largely lost through vesicle shedding . Necrotic cell with plasma membrane poorly defined Healthy cell with normal nucleus Shriveled and shrunken

105. Immune response to intravesicular bacteria is coordinated by TH1 cells

109. Molecular complexes recognized by both B and T cells make effective vaccines

111. Summary: The properties of the P-APC