41) What do many of the different kinds of allergies have in common?

A) They cause histamine release.

B) They result in high blood pressure.

C) They contribute to autoimmune disorders.

D) All allergens are living things.

42) Why may a transplanted organ be rejected by the immune system?

A) The organ contains different blood antigens.

B) The immune system produces a severe allergic response.

C) The organ contains different T cells.

D) The organ contains different B cells.

E) The organ has non-self surface recognition molecules.

43) Immune therapy research with potential to work in alleviating both organ rejection and autoimmune disease involves:

A) antibodies.

B) regulatory T cells.

C) vaccines.

D) cytotoxic T cell action.

44) An antigen is any foreign substance that elicits an immune response.

45) Macrophages and dendritic cells can both be antigen presenting cells.

46) Complement proteins are antibodies produced by skin cells.

47) Dendritic cells are the histamine-producing cells of the immune system.

48) Stomach acid is one of our natural defenses against bacteria in food.

49) Cytokines are molecules that cut holes in bacterial membranes.

50) There are different Toll-Like Receptors for bacteria and viruses.