5.3 - T cells + cell-mediated immunity

• Where do T cells mature ?

  Thymus
• What type of immunity are T cells involved with ?

  Cell-mediated
• Where does a cell-mediated response target ?

  Intracellular
• What are APCs ?

  Antigen-presenting cells that display antigens of other cells on their own cell surface membrane
• How do T cells detect antigens on APCs ?

  Very specific T cell receptors
• How are T cells activated ?

  When they encounter and bind to their specific antigen on an APC
• 1st stage of T cell response ?

  Phagocytosis by phagocyte destroys pathogen
• 2nd stage of T cell response ?

  Phagocyte displays antigens to become an APC
• 3rd stage of T cell response ?

  Receptors on a specific helper T cell bind to the antigen as they’re complimentary
• 4th stage of T cell response ?

  The attachment activates the T cell to divide rapidly by mitosis and form a clone of genetically identical cells
• What do the cloned T cells produce ?

  Cytokines
• What 4 things to cytokines stimulate ?

  increased rate of phagocytosis, B cells to mature and divide, activation of cytotoxic T cells, development into memory cells
• What protein do cytotoxic T cells produce ?

  Perforin
• What does perforin do ?

  Makes holes in the cell-membrane
• Why is the production of perforin important ?

  Means cell membranes become freely permeable to allow toxin secretion into the cell