How does affinity maturation occur?

1. AID produces uracils in the Ig V region of the DNA 2. these uracils are often converted to thymidines or are removed. these mutations are called somatic hypermutations 3. the result is different B cell clones that have varying affinities to the antigen 4. the B cells with the highest affinity are selected by follicular dendritic cells (FDCs)