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Immune Tolerance quiz

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  • What is immune tolerance?
    Immune tolerance is the ability of the immune system to ignore harmless antigens while attacking harmful ones.
  • Why is immune tolerance important for the immune system?
    It prevents the immune system from attacking the body's own healthy cells, reducing the risk of autoimmune diseases.
  • What can happen if immune tolerance fails?
    The immune system may attack healthy, uninfected cells, leading to autoimmune diseases.
  • In the football analogy, what does the quarterback represent?
    The quarterback represents the immune system.
  • According to the football analogy, what do the teammates and opponents represent?
    Teammates represent harmless antigens, and opponents represent harmful antigens.
  • What are the two main types of immune tolerance mechanisms?
    The two main types are central immune tolerance and peripheral immune tolerance.
  • Where does central immune tolerance occur for T cells and B cells?
    Central immune tolerance occurs in the thymus for T cells and in the bone marrow for B cells.
  • What process is involved in central immune tolerance?
    Central immune tolerance involves negative selection, which eliminates self-reacting T and B cells before they leave the primary lymphoid organs.
  • What is the main function of peripheral immune tolerance?
    Peripheral immune tolerance eliminates or inactivates self-reacting T and B cells that escaped central tolerance, using both negative and positive selection.
  • What is negative selection in immune tolerance?
    Negative selection is the process of eliminating immune cells that react to self or harmless antigens, usually through apoptosis.
  • What is positive selection in immune tolerance?
    Positive selection promotes the survival of immune cells that can appropriately bind to MHC molecules.
  • What happens to T and B cells that bind to harmless antigens during negative selection?
    They are eliminated through apoptosis to prevent them from attacking the body's own tissues.
  • Approximately what percentage of T and B cells survive both central and peripheral tolerance mechanisms?
    Only about 5% of T and B cells survive; the remaining 95% undergo apoptosis.
  • What does it mean for a T or B cell to become anergic?
    An anergic cell is unresponsive and eventually undergoes apoptosis, preventing it from causing harm.
  • Why are the T and B cells that survive tolerance mechanisms considered effective?
    They are effective because they can target harmful antigens without attacking harmless or self-antigens.