試題詳解

19. The switch of one B cell from producing one class of antibody to another antibody class that is responsive to the same antigen is due to
(A) the rearrangement of immunoglobulin heavy-chain C region DNA.
(B) a switch in the kind of antigen-presenting cell that is involved in the immune response.
(C) a patient's reaction to the first kind of antibody made by the plasma cells.
(D) the rearrangement of V region genes in that clone of responsive B cells.