Antibody class switching rearranges the genes within a B cell which controls the type of antibody secreted by the plasma B cell. During this gene rearrangement, the ______ region of the antibody is affected and the ______ region of the antibody is unaffected. This means that antibody class switching is antigen specificity ______.

• A. Constant region; Variable region; Independent.
• B. Variable region; Constant region; Independent.
• C. Constant region; Variable region; Dependent.
• D. Variable region; Constant region; Dependent.

Answer: (A)

Verified step by step guidance

1. Understand the structure of an antibody: Antibodies are composed of two main regions, the constant region and the variable region. The constant region determines the class of the antibody, while the variable region is responsible for antigen specificity.
2. Learn about antibody class switching: This process involves changes in the constant region of the antibody, allowing a B cell to produce different classes of antibodies (e.g., IgG, IgA, IgE) while maintaining the same antigen specificity.
3. Recognize the unaffected region: During class switching, the variable region remains unchanged, ensuring that the antibody continues to recognize the same antigen.
4. Determine the relationship with antigen specificity: Since the variable region is unaffected, antibody class switching is independent of antigen specificity. The specificity remains constant despite changes in the antibody class.
5. Select the correct answer based on the understanding: The correct answer is 'Constant region; Variable region; Independent,' as class switching affects the constant region, leaves the variable region unchanged, and does not alter antigen specificity.