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) mutation in the genes of that B cell, induced by exposure to the antigen.
B) the rearrangement of V region genes in that clone of responsive B cells.
C) a switch in the kind of antigen-presenting cell that is involved in the immune response.
D) a patient's reaction to the first kind of antibody made by the plasma cells.
E) the rearrangement of immunoglobulin heavy-chain C region DNA.

Question

Quizplus · Accepted Answer

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 the rearrangement of immunoglobulin heavy-chain C region DNA. This process is called class switching and occurs after the initial activation of B cells by an antigen. Through class switching, B cells change the class of antibody they produce (e.g., from IgM to IgG) without changing the specificity of their receptors. This switch is accomplished by a process called DNA recombination, which involves the deletion or inversion of DNA segments that code for the current antibody class and the insertion of a different C region gene that codes for the new antibody class.

The Switch of One B Cell from Producing One Class