[Campbell Biology P.1019] The text states that a person with Type A blood does not make antib... | Practice Question

The text states that a person with Type A blood does not make antibodies against the bacterial epitope similar to the A carbohydrate. What is the immunological principle behind this phenomenon?

  • A: Type A individuals lack the genes to produce antibodies against A carbohydrates.
  • B: Lymphocytes reactive with the body's own cells and molecules (like the A carbohydrate) were inactivated or eliminated during development.
  • C: The A carbohydrate is too small to elicit an immune response on its own.
  • D: The immune system only produces antibodies against foreign carbohydrates, not those similar to self.

Explanation

The immune system has mechanisms to prevent it from attacking the body's own tissues, a process known as immunological tolerance. For ABO blood groups, any lymphocytes that would be reactive to self-carbohydrates like the A carbohydrate in a Type A individual are either inactivated anergy or eliminated clonal deletion during their development in the bone marrow and thymus. This ensures that the individual does not produce antibodies against their own blood group antigens.