Affinity Maturation

Affinity maturation is the process by which the immune system improves the binding strength of antibodies to a specific antigen through successive rounds of mutation and selection. Following the initial encounter described by clonal selection theory, activated B cells undergo somatic hypermutation in their antibody genes, producing a population of variants with slightly different binding affinities. Those variants that bind more strongly receive stronger survival signals and proliferate more; weaker variants die off. The result is a micro-evolutionary process within the organism that produces antibodies of increasing specificity and strength over days to weeks. Affinity maturation is one of the clearest biological examples of adaptive dynamics operating on a compressed timescale, and it demonstrates that evolutionary principles apply not only to species but to any system exhibiting heredity, variation, and differential survival. See also: Clonal Selection Theory, Evolution, Natural Selection, Adaptive dynamics