T Cell Development and Activation PDF

Cytokines vs. Cytotoxicity 52 Antigen Recognition by T Cells CD4 and CD8 53  Antigen Recognition by T Cells Intracellular Pathogens: Cytokine vs Cytotoxicity 54  Ac...

Cytokines vs. Cytotoxicity 52 Antigen Recognition by T Cells CD4 and CD8 53  Antigen Recognition by T Cells Intracellular Pathogens: Cytokine vs Cytotoxicity 54  Activation of CD8 T Cells Strong Co-stimulation Required 55  Cytotoxic T Cells Destroy Virus-Infected Cells 56  Cytotoxic T Cells One CTL Can Kill Multiple Infected Cells The cytotoxins released by CD8 T cells are: - Perforin, which forms pores in cell membranes of target cells, - Granzymes, which are serine esterases that enter the cytoplasm of target cells, inducing apoptosis, - Granulysin, which is a membrane-perturbing protein that works with perforin and serglycin to form pores in target cells. 57  Clearance of a Pathogen CD4 Cell Cooperation With CD8 Cells 58 Summary of B and T Cell Development Cell Fates 59 Summary of B and T Cell Development Gene Rearrangements 60  Summary of T Cell Development From Bone Marrow to Thymus to Periphery 61 Summary of T Cell Selection T Cell Fates in the Thymus 62 T Cell Homing, Activation, and Effector Function 63 Summary of T Cell Effector Responses Cytokines vs. Cytotoxicity 64  Cytokine Summary Table Cytokines are pleiotropic and redundant Know the cytokines that we have discussed in detail during these lectures Try to remember them in the context of their impact on immunity. 65 ILC: Innate Lymphoid Cell Helper T Cell Responses Th1 Cells 66 Helper T Cell Responses Th2 Cells 67 Helper T Cell Responses Th17 Cells 68 Summary of Effector Cell Influences on Host Cells 69 Comparison of Antibodies and TCR 70  Primary and Secondary Response to Infection Primary immune response has a lag before antibodies are detected. Low affinity IgM antibodies are detected first. Germinal center reaction yields increased affinity and isotype switching (IgG). Secondary response induces a faster, stronger memory response. Vaccination is an attempt to induce a primary response to a pathogen so that natural exposure will induce strong, rapid clearance without evidence of illness. 71  Pathogen Evasion of Immune Response Most effective pathogens have evolved mechanisms to evade the host responses (even if only briefly) in order to gain an advantage during an infection. Total removal of the MHC does make the cell more recognizable by NK cells (removes the inhibitory 72 signal).