*5.2.2.3.4 Impacts of mutations on affinity of BCR and secreted Ig*

The low affinity of antibodies produced during the primary immune response tends to increase as the immune response progresses, thanks to the numerous point mutations in hypervariable regions of the IG V gene of the antigen-specific B-cell clones.

Most mutations have no positive effect on the affinity of BCR or Ig produced, and frequently negatively affect their ability to bind antigen inducing B-cell activation.

Of the four types of possible mutations-silent, neutral, deleterious, and positiveonly deleterious mutations and positive mutations have an effect on the affinity of the antigen for its appropriate BCR:


iii.Silent or neutral mutations have no noticeable effect on antigen affinity. They preserve the amino acid sequence and do not alter the structure of proteins and are dispersed throughout the V region [48].
