The process involves two main cellular mechanisms: somatic hypermutation and clonal selection.
- Somatic Hypermutation: This involves the introduction of point mutations in the variable regions of immunoglobulin genes in activated B cells. The enzyme activation-induced cytidine deaminase (AID) plays a critical role in this process by deaminating cytosine bases, which leads to mutations. - Clonal Selection: B cells expressing high-affinity receptors are selected for survival and proliferation. This selection is mediated by interactions with antigens presented on follicular dendritic cells and help from T follicular helper cells (Tfh).
