Activation of T Lymphocytes Chapter 9

1. Introduction
   1. recognizing Ag twice
      1. Naive T cells = "resting state"
      2. Activated T cells
      3. Effector T cells & Memory T cells
         1. CD4⁺ = helper T cells
         2. CD8⁺ = Cytotoxic T Lymphocytes (CTLs)
   1. Decline
2. Signals
   1. 1°
   2. 2° = costimulators
      1. costimulation
      1. cell surface
         1. on T cell = CD28
         2. on APC - B7
         3. other receptors
      2. cytokines
         1. IL-2
3. Activated T cell responses
   1. Cytokines secretion
   2. proliferation
   3. differentiation into effector & memory T cells
4. Memory T cells
   1. Background
   2. Properties
      1. prolonged survival
      2. respond rapidly
      3.  number
      4. migrate to any tissue
      5. less dependent of costimulation
      6. always undergoing a slow proliferation
      7. generate new effector T cells