AH 3121 Chapter Notes - Chapter 5: Mhc Class Ii, Lymph Node, T Helper Cell
Document Summary
Cell-mediated immune responses activation of t lymphocytes by. Purpose of cell-mediated immunity: to eradicate intracellular infections. Organisms able to survive within phagocyte vesicles. Viruses and other organisms that infect non-phagocytic cells: mediated by t cells. Organisms able to survive within phagocyte: if an organism escapes from the phagolysosome, it is protected from the destructive enzymes within, many microbes have learned how to survive in a phagocyte. T helper cells: surface marker cd4, activated by extracellular antigens/microbes, stimulate macrophage killing of engulfed organisms. T cytotoxic cells: surface marker cd8, activated by intracellular antigen/microbes, stimulate killing of infected cells. Steps in activation of t cells: antigen recognition by na ve t cells. Avery welch ah 3121 immunology week 4 chapter 5 notes 9/22/15-/9/24/15. Second signals are received from the organism and/or from the innate immune system. Additional signals (cytokines, costimulators) from the apc are also required.
