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Immune Tolerance quiz

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  • What is immune tolerance?
    Immune tolerance is the immune system's ability to ignore or tolerate harmless antigens while targeting harmful ones.
  • Why is immune tolerance important for the immune system?
    It prevents the immune system from attacking healthy cells and causing autoimmune diseases.
  • What can happen if immune tolerance fails?
    The immune system may attack the body's own healthy cells, leading to autoimmune diseases.
  • Where does central immune tolerance occur?
    Central immune tolerance occurs in the primary lymphoid organs: the thymus for T cells and 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.
  • Where does peripheral immune tolerance take place?
    Peripheral immune tolerance occurs in secondary lymphoid organs, such as lymph nodes.
  • What two types of selection are involved in peripheral immune tolerance?
    Peripheral immune tolerance involves both positive selection and negative selection of mature T and B cells.
  • What is negative selection in immune tolerance?
    Negative selection eliminates cells that react to self or harmless antigens, usually through apoptosis.
  • What is positive selection in immune tolerance?
    Positive selection promotes survival of cells that appropriately bind to MHC molecules.
  • Approximately what percentage of T and B cells survive the tolerance mechanisms?
    Only about 5% of T and B cells survive; around 95% are eliminated during tolerance mechanisms.
  • What is the football analogy for immune tolerance?
    The immune system is like a quarterback who must distinguish teammates (harmless antigens) from opponents (harmful antigens) to do its job properly.
  • What happens to self-reacting T and B cells during central tolerance?
    They are eliminated by apoptosis before leaving the primary lymphoid organs.
  • What does it mean if a cell becomes anergic during peripheral tolerance?
    It means the cell becomes unresponsive and will eventually undergo apoptosis.
  • Why is negative selection considered 'negative'?
    Because it results in the elimination or death of cells that bind to self or harmless antigens.
  • What is the main goal of immune tolerance mechanisms?
    To ensure that only immune cells that target harmful antigens survive, while those that could attack harmless or self-antigens are eliminated.