A. increased blood flow to damaged area brings in defensive cells and delivers clotting elements
A major difference between active and passive immunity is that active immunity requires
B. direct exposure to a living or simulated pathogen
B cells are usually activated into clonal proliferation into plasma cells and memory cells as a consequence of
A.antigens binding to antigen receptors on the B cells
B.activated Helper T cells binding to class II MHC-antigen complexes on B cells
C.Helper T cells secreting cytokines
D.answers "a" and "b" above
E.answers "a", "b" & "c" above
Answer Key: E
Chemicals that cause body's temperature to rise, resulting in fever are
In which of the following situations will helper T cells be activated?
E. when an antigen is displayed by a dendritic cell
Phagocytosis of microbes by macrophages is enhanced by
A.the binding of antibodies to the surface of microbes
B.antibody-mediated agglutination of microbes
C.the release of cytokines by activated B cells
D.A and B only
E.A, B, and C
Answer Key: D
Sebaceous fluids produced by the skin protect the body against infection by
D. maintaining a pH that is conducive to the growth of normal flora
The complement reaction
E. all of these
Which antibody type is most effective at agglutination responses?
Which of the following cell types are responsible for initiating a secondary immune response?
B. memory cells
Which of the following is a mechanism of antibody action?
B. all of these
Why can normal immune responses be described as polyclonal?
D. Diverse antibodies are produced for different epitopes of a specific antigen.
An allergy occurs when
D. antigen binds to antibodies on the surfaces of mast cells causing the release of histamine
A transfusion of type A blood given to a person who has type O blood would result in which of the following?
A. the recipient's anti-A antibodies clumping the donated red blood cells
CD4 and CD8 are proteins
B. that are present on the surface of T cells where they enhance cellular interaction.