T cell response

• • T cells/T lymphocytes are a type of WBC involved in SIR
  • produced in bone marrow and mature in thymus
• types of T cells

  • T helper= release chemical signalling molecules to activate B cells
  • T killer= binds to and destroys infected cells
  • T memory= remain in blood and enable faster SIR
• stage 1= T CELL ACTIVATION

  1. bacterium with antigens engulfed by macrophage
  2. macrophage present antigens on its surface(APC)- antigens are displayed on major histone complexes(MHC's)
  3. APC binds to a T helper cell w complementary receptors
  4. T helper cell is activated and divides via mitosis to form ACTIVE T-helper cells and T memory cells
• stage 2= EFFECTOR STAGE(role of T-helper)

  1. B cells bind to antigens on bacterium becoming an APC
  2. an activated T helper cell(from activation) with complementary receptors binds to the antigens on the B cell APC- producing cytokines
  3. cytokines stimulate the B cell to divide by mitosis and form B memory cells and B effector cells
  4. B-effector cells differentiate into plasma cells- secrete antibodies
  5. B-memory cells remain for immediate specific response
• plasma cells secrete antibodies for:

  1. agglutination- clumping for phagocytes
  2. lysis- bursting of bacterial cells
  3. opsonisation- coat and mark pathogens for phagocytes
  4. neutralisation- neutralising harmful toxins