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Somatic hypermutation and allelic exclusion.

1. Somatic hypermutation of antibody variable regions can occur during an immune response. It allows daughter cells to produce antibodies with a slightly different V region than the parent cell. Give one reason why this might be important for the efficacy of the antibody response. Explain why mutations of the framework region of an antibody might be more detrimental to the antibody than mutations in CDR's

2. You learned that a B-cell only uses one allele of it's heavy and light chains. What is this process called?
What problems may arise if during an immune response if more than one gene was used in each B-cell?

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1) Although there is enough diversity in the range of antibodies made by different B cells to recognize almost any foreign protein, some of these antibodies may bind to the target protein weakly. The ability to make small changes to the V region allows the B cells to fine tune the antibody produced, and the B cells producing the highest affinity antibody will be selected, resulting in an overall increase in the affinity of antibody produced, ...

Solution Summary

This solution details how somatic hypermutation is beneficial to the antibody response and why it is limited to certain regions of the antibody molecule. It also explains why each B cell only expresses one of it's rearranged antibody genes by a process called allelic exclusion.