Affinity maturation refers to the process by which B cells increase the binding affinity of their antibodies to an antigen. The term affinity maturation is often used interchangeably with somatic hypermutation, which refers to the process by which B cells undergo genetic changes in their variable region to generate new and improved antibodies. Some other possible synonyms for affinity maturation include enhanced antibody specificity, antibody fine-tuning, antigen-driven selection, and immunoglobulin optimization. These terms all refer to the same basic process of improving the affinity and specificity of antibodies through genetic changes and selection. Understanding affinity maturation is critical for developing new vaccines and therapies to fight disease.